How to remove all event handlers from an event

Question

To create a new event handler on a control you can do this  c Click    new EventHandler mainFormButton Click     or this  c Click    mainFormButton Click    and to remove an event handler you can do this  c Click -  mainFormButton Click    But how do you remove all event handlers from an event

User · Answer

Accepted answer is not full  It doesn t work for events declared as  add  remove    Here is working code   public static void ClearEventInvocations this object obj  string eventName        var fi   obj GetType   GetEventField eventName       if  fi    null  return      fi SetValue obj  null      private static FieldInfo GetEventField this Type type  string eventName        FieldInfo field   null      while  type    null                   Find events defined as field            field   type GetField eventName  BindingFlags Static   BindingFlags Instance   BindingFlags NonPublic           if  field    null  amp  amp   field FieldType    typeof MulticastDelegate     field FieldType IsSubclassOf typeof MulticastDelegate                 break              Find events defined as property   add  remove               field   type GetField  EVENT     eventName ToUpper    BindingFlags Static   BindingFlags Instance   BindingFlags NonPublic           if  field    null              break          type   type BaseType            return field

User · Answer

I found a solution on the MSDN forums  The sample code below will remove all Click events from button1  public partial class Form1   Form       public Form1                 InitializeComponent             button1 Click    button1 Click          button1 Click    button1 Click2          button2 Click    button2 Click             private void button1 Click object sender  EventArgs e     gt  MessageBox Show  quot Hello quot        private void button1 Click2 object sender  EventArgs e    gt  MessageBox Show  quot World quot        private void button2 Click object sender  EventArgs e     gt  RemoveClickEvent button1        private void RemoveClickEvent Button b                FieldInfo f1   typeof Control  GetField  quot EventClick quot                BindingFlags Static   BindingFlags NonPublic            object obj   f1 GetValue b           PropertyInfo pi   b GetType   GetProperty  quot Events quot                 BindingFlags NonPublic   BindingFlags Instance            EventHandlerList list    EventHandlerList pi GetValue b  null           list RemoveHandler obj  list obj

User · Answer

If you reaallly have to do this    it ll take reflection and quite some time to do this  Event handlers are managed in an event-to-delegate-map inside a control  You would need to   Reflect and obtain this map in the control instance  Iterate for each event  get the delegate   each delegate in turn could be a chained series of event handlers  So call obControl RemoveHandler event  handler     In short  a lot of work  It is possible in theory    I never tried something like this   See if you can have better control discipline over the subscribe-unsubscribe phase for the control

User · Answer

This is not an answer to the OP  but I thought I d post this here in case it can help others           lt summary gt        Method to remove a  single  SocketAsyncEventArgs Completed event handler  This is        partially based on information found here  http   stackoverflow com a 91853 253938              But note that this may not be a good idea  being very  Net implementation-dependent  Note        in particular use of  m Completed  instead of  Completed          lt  summary gt    private static void RemoveCompletedEventHandler SocketAsyncEventArgs eventArgs           FieldInfo fieldInfo   typeof SocketAsyncEventArgs  GetField  m Completed                                                    BindingFlags Instance   BindingFlags NonPublic        eventArgs Completed -   EventHandler lt SocketAsyncEventArgs gt  fieldInfo GetValue eventArgs

User · Answer

From Removing All Event Handlers      Directly no  in large part because you   cannot simply set the event to null       Indirectly  you could make the actual   event private and create a property   around it that tracks all of the   delegates being added subtracted to   it       Take the following   List lt EventHandler gt  delegates   new List lt EventHandler gt      private event EventHandler MyRealEvent   public event EventHandler MyEvent       add               MyRealEvent    value          delegates Add value              remove               MyRealEvent -  value          delegates Remove value            public void RemoveAllEvents         foreach EventHandler eh in delegates                MyRealEvent -  eh            delegates Clear

User · Answer

I hated any complete solutions shown here  I did a mix and tested now  worked for any event handler   public class MyMain       public void MyMethod             AnotherClass TheEventHandler    DoSomeThing             private void DoSomething object sender  EventArgs e            Debug WriteLine  I did something            AnotherClass ClearAllDelegatesOfTheEventHandler              public static class AnotherClass        public static event EventHandler TheEventHandler       public static void ClearAllDelegatesOfTheEventHandler              foreach  Delegate d in TheEventHandler GetInvocationList                          TheEventHandler -   EventHandler d                      Easy  Thanks for Stephen Punak   I used it because I use a generic local method to remove the delegates and the local method was called after different cases  when different delegates are setted

User · Answer

I found a solution on the MSDN forums  The sample code below will remove all Click events from button1  public partial class Form1   Form       public Form1                 InitializeComponent             button1 Click    button1 Click          button1 Click    button1 Click2          button2 Click    button2 Click             private void button1 Click object sender  EventArgs e     gt  MessageBox Show  quot Hello quot        private void button1 Click2 object sender  EventArgs e    gt  MessageBox Show  quot World quot        private void button2 Click object sender  EventArgs e     gt  RemoveClickEvent button1        private void RemoveClickEvent Button b                FieldInfo f1   typeof Control  GetField  quot EventClick quot                BindingFlags Static   BindingFlags NonPublic            object obj   f1 GetValue b           PropertyInfo pi   b GetType   GetProperty  quot Events quot                 BindingFlags NonPublic   BindingFlags Instance            EventHandlerList list    EventHandlerList pi GetValue b  null           list RemoveHandler obj  list obj

User · Answer

It doesn t do any harm to delete a non-existing event handler  So if you know what handlers there might be  you can simply delete all of them  I just had similar case  This may help in some cases   Like      Add handlers    if  something        c Click    DoesSomething    else       c Click    DoesSomethingElse        Remove handlers    c Click -  DoesSomething  c Click -  DoesSomethingElse

User · Answer

Stephen has right  It is very easy   public event EventHandler lt Cles graph doivent etre redessines gt  les graph doivent etre redessines  public void remove event         if  this les graph doivent etre redessines    null                foreach  EventHandler lt Cles graph doivent etre redessines gt  F les graph doivent etre redessines in this les graph doivent etre redessines GetInvocationList                          this les graph doivent etre redessines -  F les graph doivent etre redessines

User · Answer

This page helped me a lot  The code I got from here was meant to remove a click event from a button  I need to remove double click events from some panels and click events from some buttons  So I made a control extension  which will remove all event handlers for a certain event   using System  using System Collections Generic  using System ComponentModel  using System Drawing  using System Windows Forms  using System Reflection  public static class EventExtension       public static void RemoveEvents lt T gt  this T target  string eventName  where T Control               if  ReferenceEquals target  null   throw new NullReferenceException  Argument   target   may not be null             FieldInfo fieldInfo   typeof Control  GetField eventName  BindingFlags Static   BindingFlags NonPublic           if  ReferenceEquals fieldInfo  null   throw new ArgumentException              string Concat  The control    typeof T  Name    does not have a property with the name      eventName         nameof eventName            object eventInstance   fieldInfo GetValue target           PropertyInfo propInfo   typeof T  GetProperty  Events   BindingFlags NonPublic   BindingFlags Instance           EventHandlerList list    EventHandlerList propInfo GetValue target  null           list RemoveHandler eventInstance  list eventInstance              Now  the usage of this extenstion  If you need to remove click events from a button   Button button   new Button    button RemoveEvents nameof button EventClick      If you need to remove doubleclick events from a panel   Panel panel   new Panel    panel RemoveEvents nameof panel EventDoubleClick      I am not an expert in C   so if there are any bugs please forgive me and kindly let me know about it

User · Answer

Wow  I found this solution  but nothing worked like I wanted  But this is so good   EventHandlerList listaEventos   private void btnDetach Click object sender  EventArgs e        listaEventos   DetachEvents comboBox1      private void btnAttach Click object sender  EventArgs e        AttachEvents comboBox1  listaEventos      public EventHandlerList DetachEvents Component obj        object objNew   obj GetType   GetConstructor new Type        Invoke new object             PropertyInfo propEvents   obj GetType   GetProperty  Events   BindingFlags NonPublic   BindingFlags Instance        EventHandlerList eventHandlerList obj    EventHandlerList propEvents GetValue obj  null       EventHandlerList eventHandlerList objNew    EventHandlerList propEvents GetValue objNew  null        eventHandlerList objNew AddHandlers eventHandlerList obj       eventHandlerList obj Dispose         return eventHandlerList objNew     public void AttachEvents Component obj  EventHandlerList eventos        PropertyInfo propEvents   obj GetType   GetProperty  Events   BindingFlags NonPublic   BindingFlags Instance        EventHandlerList eventHandlerList obj    EventHandlerList propEvents GetValue obj  null        eventHandlerList obj AddHandlers eventos

User · Answer

If you reaallly have to do this    it ll take reflection and quite some time to do this  Event handlers are managed in an event-to-delegate-map inside a control  You would need to   Reflect and obtain this map in the control instance  Iterate for each event  get the delegate   each delegate in turn could be a chained series of event handlers  So call obControl RemoveHandler event  handler     In short  a lot of work  It is possible in theory    I never tried something like this   See if you can have better control discipline over the subscribe-unsubscribe phase for the control

User · Answer

Wow  I found this solution  but nothing worked like I wanted  But this is so good   EventHandlerList listaEventos   private void btnDetach Click object sender  EventArgs e        listaEventos   DetachEvents comboBox1      private void btnAttach Click object sender  EventArgs e        AttachEvents comboBox1  listaEventos      public EventHandlerList DetachEvents Component obj        object objNew   obj GetType   GetConstructor new Type        Invoke new object             PropertyInfo propEvents   obj GetType   GetProperty  Events   BindingFlags NonPublic   BindingFlags Instance        EventHandlerList eventHandlerList obj    EventHandlerList propEvents GetValue obj  null       EventHandlerList eventHandlerList objNew    EventHandlerList propEvents GetValue objNew  null        eventHandlerList objNew AddHandlers eventHandlerList obj       eventHandlerList obj Dispose         return eventHandlerList objNew     public void AttachEvents Component obj  EventHandlerList eventos        PropertyInfo propEvents   obj GetType   GetProperty  Events   BindingFlags NonPublic   BindingFlags Instance        EventHandlerList eventHandlerList obj    EventHandlerList propEvents GetValue obj  null        eventHandlerList obj AddHandlers eventos

User · Answer

From Removing All Event Handlers      Directly no  in large part because you   cannot simply set the event to null       Indirectly  you could make the actual   event private and create a property   around it that tracks all of the   delegates being added subtracted to   it       Take the following   List lt EventHandler gt  delegates   new List lt EventHandler gt      private event EventHandler MyRealEvent   public event EventHandler MyEvent       add               MyRealEvent    value          delegates Add value              remove               MyRealEvent -  value          delegates Remove value            public void RemoveAllEvents         foreach EventHandler eh in delegates                MyRealEvent -  eh            delegates Clear

User · Answer

I found a solution on the MSDN forums  The sample code below will remove all Click events from button1  public partial class Form1   Form       public Form1                 InitializeComponent             button1 Click    button1 Click          button1 Click    button1 Click2          button2 Click    button2 Click             private void button1 Click object sender  EventArgs e     gt  MessageBox Show  quot Hello quot        private void button1 Click2 object sender  EventArgs e    gt  MessageBox Show  quot World quot        private void button2 Click object sender  EventArgs e     gt  RemoveClickEvent button1        private void RemoveClickEvent Button b                FieldInfo f1   typeof Control  GetField  quot EventClick quot                BindingFlags Static   BindingFlags NonPublic            object obj   f1 GetValue b           PropertyInfo pi   b GetType   GetProperty  quot Events quot                 BindingFlags NonPublic   BindingFlags Instance            EventHandlerList list    EventHandlerList pi GetValue b  null           list RemoveHandler obj  list obj

User · Answer

Accepted answer is not full  It doesn t work for events declared as  add  remove    Here is working code   public static void ClearEventInvocations this object obj  string eventName        var fi   obj GetType   GetEventField eventName       if  fi    null  return      fi SetValue obj  null      private static FieldInfo GetEventField this Type type  string eventName        FieldInfo field   null      while  type    null                   Find events defined as field            field   type GetField eventName  BindingFlags Static   BindingFlags Instance   BindingFlags NonPublic           if  field    null  amp  amp   field FieldType    typeof MulticastDelegate     field FieldType IsSubclassOf typeof MulticastDelegate                 break              Find events defined as property   add  remove               field   type GetField  EVENT     eventName ToUpper    BindingFlags Static   BindingFlags Instance   BindingFlags NonPublic           if  field    null              break          type   type BaseType            return field

User · Answer

From Removing All Event Handlers      Directly no  in large part because you   cannot simply set the event to null       Indirectly  you could make the actual   event private and create a property   around it that tracks all of the   delegates being added subtracted to   it       Take the following   List lt EventHandler gt  delegates   new List lt EventHandler gt      private event EventHandler MyRealEvent   public event EventHandler MyEvent       add               MyRealEvent    value          delegates Add value              remove               MyRealEvent -  value          delegates Remove value            public void RemoveAllEvents         foreach EventHandler eh in delegates                MyRealEvent -  eh            delegates Clear

User · Answer

I just found How to suspend events when setting a property of a WinForms control  It will remove all events from a control   namespace CMessWin05       public class EventSuppressor               Control  source          EventHandlerList  sourceEventHandlerList          FieldInfo  headFI          Dictionary lt object  Delegate   gt   handlers          PropertyInfo  sourceEventsInfo          Type  eventHandlerListType          Type  sourceType            public EventSuppressor Control control                        if  control    null                  throw new ArgumentNullException  control    An instance of a control must be provided                   source   control               sourceType    source GetType                 sourceEventsInfo    sourceType GetProperty  Events   BindingFlags Instance   BindingFlags NonPublic                sourceEventHandlerList    EventHandlerList  sourceEventsInfo GetValue  source  null                eventHandlerListType    sourceEventHandlerList GetType                 headFI    eventHandlerListType GetField  head   BindingFlags Instance   BindingFlags NonPublic                      private void BuildList                          handlers   new Dictionary lt object  Delegate   gt                 object head    headFI GetValue  sourceEventHandlerList               if  head    null                                Type listEntryType   head GetType                    FieldInfo delegateFI   listEntryType GetField  handler   BindingFlags Instance   BindingFlags NonPublic                   FieldInfo keyFI   listEntryType GetField  key   BindingFlags Instance   BindingFlags NonPublic                   FieldInfo nextFI   listEntryType GetField  next   BindingFlags Instance   BindingFlags NonPublic                   BuildListWalk head  delegateFI  keyFI  nextFI                                    private void BuildListWalk object entry  FieldInfo delegateFI  FieldInfo keyFI  FieldInfo nextFI                        if  entry    null                                Delegate dele    Delegate delegateFI GetValue entry                   object key   keyFI GetValue entry                   object next   nextFI GetValue entry                    Delegate   listeners   dele GetInvocationList                    if listeners    null  amp  amp  listeners Length  gt  0                       handlers Add key  listeners                    if  next    null                                        BuildListWalk next  delegateFI  keyFI  nextFI                                                      public void Resume                         if   handlers    null                  throw new ApplicationException  Events have not been suppressed                  foreach  KeyValuePair lt object  Delegate   gt  pair in  handlers                                for  int x   0  x  lt  pair Value Length  x                         sourceEventHandlerList AddHandler pair Key  pair Value x                                handlers   null                     public void Suppress                         if   handlers    null                  throw new ApplicationException  Events are already being suppressed                  BuildList                 foreach  KeyValuePair lt object  Delegate   gt  pair in  handlers                                for  int x   pair Value Length - 1  x  gt   0  x--                       sourceEventHandlerList RemoveHandler pair Key  pair Value x

User · Answer

This page helped me a lot  The code I got from here was meant to remove a click event from a button  I need to remove double click events from some panels and click events from some buttons  So I made a control extension  which will remove all event handlers for a certain event   using System  using System Collections Generic  using System ComponentModel  using System Drawing  using System Windows Forms  using System Reflection  public static class EventExtension       public static void RemoveEvents lt T gt  this T target  string eventName  where T Control               if  ReferenceEquals target  null   throw new NullReferenceException  Argument   target   may not be null             FieldInfo fieldInfo   typeof Control  GetField eventName  BindingFlags Static   BindingFlags NonPublic           if  ReferenceEquals fieldInfo  null   throw new ArgumentException              string Concat  The control    typeof T  Name    does not have a property with the name      eventName         nameof eventName            object eventInstance   fieldInfo GetValue target           PropertyInfo propInfo   typeof T  GetProperty  Events   BindingFlags NonPublic   BindingFlags Instance           EventHandlerList list    EventHandlerList propInfo GetValue target  null           list RemoveHandler eventInstance  list eventInstance              Now  the usage of this extenstion  If you need to remove click events from a button   Button button   new Button    button RemoveEvents nameof button EventClick      If you need to remove doubleclick events from a panel   Panel panel   new Panel    panel RemoveEvents nameof panel EventDoubleClick      I am not an expert in C   so if there are any bugs please forgive me and kindly let me know about it

User · Answer

If you reaallly have to do this    it ll take reflection and quite some time to do this  Event handlers are managed in an event-to-delegate-map inside a control  You would need to   Reflect and obtain this map in the control instance  Iterate for each event  get the delegate   each delegate in turn could be a chained series of event handlers  So call obControl RemoveHandler event  handler     In short  a lot of work  It is possible in theory    I never tried something like this   See if you can have better control discipline over the subscribe-unsubscribe phase for the control

User · Answer

From Removing All Event Handlers      Directly no  in large part because you   cannot simply set the event to null       Indirectly  you could make the actual   event private and create a property   around it that tracks all of the   delegates being added subtracted to   it       Take the following   List lt EventHandler gt  delegates   new List lt EventHandler gt      private event EventHandler MyRealEvent   public event EventHandler MyEvent       add               MyRealEvent    value          delegates Add value              remove               MyRealEvent -  value          delegates Remove value            public void RemoveAllEvents         foreach EventHandler eh in delegates                MyRealEvent -  eh            delegates Clear

User · Answer

I found another working solution by Douglas   This method removes all event handlers which are set on a specific routet event on a element  Use it like  Remove RoutedEventHandlers myImage  Image MouseLeftButtonDownEvent     Full code        lt summary gt      Removes all event handlers subscribed to the specified routed event from the specified element       lt  summary gt       lt param name  element  gt The UI element on which the routed event is defined  lt  param gt       lt param name  RoutetEvent ToRemove  gt The routed event for which to remove the event handlers  lt  param gt  public static void RemoveRoutedEventHandlers UIElement UIElement Target  RoutedEvent RoutetEvent ToRemove           Get the EventHandlersStore instance which holds event handlers for the specified element         The EventHandlersStore class is declared as internal      PropertyInfo PropertyInfo EventHandlersStore   typeof UIElement  GetProperty           EventHandlersStore   BindingFlags Instance   BindingFlags NonPublic       object oEventHandlersStore   PropertyInfo EventHandlersStore GetValue UIElement Target  null           If there s no event handler subscribed  return     if  oEventHandlersStore    null  return          Invoke the GetRoutedEventHandlers method on the EventHandlersStore instance         for getting an array of the subscribed event handlers      MethodInfo MethodInfo RoutedEventHandlers   oEventHandlersStore GetType   GetMethod           GetRoutedEventHandlers   BindingFlags Instance   BindingFlags Public   BindingFlags NonPublic       RoutedEventHandlerInfo   RoutedEventHandlerInfos    RoutedEventHandlerInfo   MethodInfo RoutedEventHandlers Invoke          oEventHandlersStore  new object     RoutetEvent ToRemove             Iteratively remove all routed event handlers from the element      foreach  RoutedEventHandlerInfo RoutedEventHandlerInfo Tmp in RoutedEventHandlerInfos          UIElement Target RemoveHandler RoutetEvent ToRemove  RoutedEventHandlerInfo Tmp Handler

User · Answer

I found another working solution by Douglas   This method removes all event handlers which are set on a specific routet event on a element  Use it like  Remove RoutedEventHandlers myImage  Image MouseLeftButtonDownEvent     Full code        lt summary gt      Removes all event handlers subscribed to the specified routed event from the specified element       lt  summary gt       lt param name  element  gt The UI element on which the routed event is defined  lt  param gt       lt param name  RoutetEvent ToRemove  gt The routed event for which to remove the event handlers  lt  param gt  public static void RemoveRoutedEventHandlers UIElement UIElement Target  RoutedEvent RoutetEvent ToRemove           Get the EventHandlersStore instance which holds event handlers for the specified element         The EventHandlersStore class is declared as internal      PropertyInfo PropertyInfo EventHandlersStore   typeof UIElement  GetProperty           EventHandlersStore   BindingFlags Instance   BindingFlags NonPublic       object oEventHandlersStore   PropertyInfo EventHandlersStore GetValue UIElement Target  null           If there s no event handler subscribed  return     if  oEventHandlersStore    null  return          Invoke the GetRoutedEventHandlers method on the EventHandlersStore instance         for getting an array of the subscribed event handlers      MethodInfo MethodInfo RoutedEventHandlers   oEventHandlersStore GetType   GetMethod           GetRoutedEventHandlers   BindingFlags Instance   BindingFlags Public   BindingFlags NonPublic       RoutedEventHandlerInfo   RoutedEventHandlerInfos    RoutedEventHandlerInfo   MethodInfo RoutedEventHandlers Invoke          oEventHandlersStore  new object     RoutetEvent ToRemove             Iteratively remove all routed event handlers from the element      foreach  RoutedEventHandlerInfo RoutedEventHandlerInfo Tmp in RoutedEventHandlerInfos          UIElement Target RemoveHandler RoutetEvent ToRemove  RoutedEventHandlerInfo Tmp Handler

User · Answer

I m actually using this method and it works perfectly  I was  inspired  by the code written by Aeonhack here   Public Event MyEvent   Protected Overrides Sub Dispose ByVal disposing As Boolean      If MyEventEvent IsNot Nothing Then         For Each d In MyEventEvent GetInvocationList   If this throws an exception  try using  ToArray             RemoveHandler MyEvent  d         Next     End If End Sub   The field MyEventEvent is hidden  but it does exist   Debugging  you can see how d target is the object actually handling the event  and d method its method  You only have to remove it   It works great  No more objects not being GC ed because of the event handlers

User · Answer

Well  here there s another solution to remove an asociated event  if you already have a method for handling the events for the control    EventDescriptor ed   TypeDescriptor GetEvents this button1  Find  MouseDown  true               Delegate delegate   Delegate CreateDelegate typeof EventHandler   this   button1 MouseDownClicked    if ed  null       ed RemoveEventHandler this button1  delegate

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removes all handlers for button    save RemoveEvents                     public static class EventExtension       public static void RemoveEvents lt T gt  this T target  where T   Control              var propInfo   typeof T  GetProperty  Events   BindingFlags NonPublic   BindingFlags Instance           var list    EventHandlerList propInfo GetValue target  null           list Dispose

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I found this answer and it almost fit my needs   Thanks to SwDevMan81 for the class   I have modified it to allow suppression and resumation of individual methods  and I thought I d post it here      This class allows you to selectively suppress event handlers for controls   You instantiate    the suppressor object with the control  and after that you can use it to suppress all events    or a single event   If you try to suppress an event which has already been suppressed    it will be ignored   Same with resuming  you can resume all events which were suppressed     or a single one   If you try to resume an un-suppressed event handler  it will be ignored     cEventSuppressor  supButton1   null    private cEventSuppressor SupButton1         get             if   supButton1    null                   supButton1   new cEventSuppressor this button1                         return  supButton1                private void button1 Click object sender  EventArgs e          MessageBox Show  Clicked            private void button2 Click object sender  EventArgs e          SupButton1 Suppress  button1 Click           private void button3 Click object sender  EventArgs e          SupButton1 Resume  button1 Click        using System  using System Collections Generic  using System Text   using System Reflection  using System Windows Forms  using System ComponentModel   namespace Crystal Utilities       public class cEventSuppressor           Control  source          EventHandlerList  sourceEventHandlerList          FieldInfo  headFI          Dictionary lt object  Delegate   gt  suppressedHandlers   new Dictionary lt object  Delegate   gt             PropertyInfo  sourceEventsInfo          Type  eventHandlerListType          Type  sourceType           public cEventSuppressor Control control                if  control    null                  throw new ArgumentNullException  control    An instance of a control must be provided                   source   control               sourceType    source GetType                 sourceEventsInfo    sourceType GetProperty  Events   BindingFlags Instance   BindingFlags NonPublic                sourceEventHandlerList    EventHandlerList  sourceEventsInfo GetValue  source  null                eventHandlerListType    sourceEventHandlerList GetType                 headFI    eventHandlerListType GetField  head   BindingFlags Instance   BindingFlags NonPublic                     private Dictionary lt object  Delegate   gt  BuildList                 Dictionary lt object  Delegate   gt  retval   new Dictionary lt object  Delegate   gt                 object head    headFI GetValue  sourceEventHandlerList               if  head    null                    Type listEntryType   head GetType                    FieldInfo delegateFI   listEntryType GetField  handler   BindingFlags Instance   BindingFlags NonPublic                   FieldInfo keyFI   listEntryType GetField  key   BindingFlags Instance   BindingFlags NonPublic                   FieldInfo nextFI   listEntryType GetField  next   BindingFlags Instance   BindingFlags NonPublic                   retval   BuildListWalk retval  head  delegateFI  keyFI  nextFI                             return retval                     private Dictionary lt object  Delegate   gt  BuildListWalk Dictionary lt object  Delegate   gt  dict                                      object entry  FieldInfo delegateFI  FieldInfo keyFI  FieldInfo nextFI                if  entry    null                    Delegate dele    Delegate delegateFI GetValue entry                   object key   keyFI GetValue entry                   object next   nextFI GetValue entry                    if  dele    null                        Delegate   listeners   dele GetInvocationList                        if  listeners    null  amp  amp  listeners Length  gt  0                            dict Add key  listeners                                                           if  next    null                        dict   BuildListWalk dict  next  delegateFI  keyFI  nextFI                                               return dict                    public void Resume                       public void Resume string pMethodName                  if   handlers    null                    throw new ApplicationException  Events have not been suppressed                 Dictionary lt object  Delegate   gt  toRemove   new Dictionary lt object  Delegate   gt                     goes through all handlers which have been suppressed   If we are resuming                 all handlers  or if we find the matching handler  add it back to the                control s event handlers             foreach  KeyValuePair lt object  Delegate   gt  pair in suppressedHandlers                     for  int x   0  x  lt  pair Value Length  x                           string methodName   pair Value x  Method Name                      if  pMethodName    null    methodName Equals pMethodName                              sourceEventHandlerList AddHandler pair Key  pair Value x                            toRemove Add pair Key  pair Value                                                                        remove all un-suppressed handlers from the list of suppressed handlers             foreach  KeyValuePair lt object  Delegate   gt  pair in toRemove                    for  int x   0  x  lt  pair Value Length  x                          suppressedHandlers Remove pair Key                                                  handlers   null                    public void Suppress                 Suppress null                     public void Suppress string pMethodName                  if   handlers    null                    throw new ApplicationException  Events are already being suppressed                  Dictionary lt object  Delegate   gt  dict   BuildList                 foreach  KeyValuePair lt object  Delegate   gt  pair in dict                    for  int x   pair Value Length - 1  x  gt   0  x--                          MethodInfo mi   pair Value x  Method                        string s1   mi Name     name of the method                       object o   pair Value x  Target                         can use this to invoke method    pair Value x  DynamicInvoke                     string methodName   pair Value x  Method Name                       if  pMethodName    null    methodName Equals pMethodName                              sourceEventHandlerList RemoveHandler pair Key  pair Value x                            suppressedHandlers Add pair Key  pair Value

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I found this answer and it almost fit my needs   Thanks to SwDevMan81 for the class   I have modified it to allow suppression and resumation of individual methods  and I thought I d post it here      This class allows you to selectively suppress event handlers for controls   You instantiate    the suppressor object with the control  and after that you can use it to suppress all events    or a single event   If you try to suppress an event which has already been suppressed    it will be ignored   Same with resuming  you can resume all events which were suppressed     or a single one   If you try to resume an un-suppressed event handler  it will be ignored     cEventSuppressor  supButton1   null    private cEventSuppressor SupButton1         get             if   supButton1    null                   supButton1   new cEventSuppressor this button1                         return  supButton1                private void button1 Click object sender  EventArgs e          MessageBox Show  Clicked            private void button2 Click object sender  EventArgs e          SupButton1 Suppress  button1 Click           private void button3 Click object sender  EventArgs e          SupButton1 Resume  button1 Click        using System  using System Collections Generic  using System Text   using System Reflection  using System Windows Forms  using System ComponentModel   namespace Crystal Utilities       public class cEventSuppressor           Control  source          EventHandlerList  sourceEventHandlerList          FieldInfo  headFI          Dictionary lt object  Delegate   gt  suppressedHandlers   new Dictionary lt object  Delegate   gt             PropertyInfo  sourceEventsInfo          Type  eventHandlerListType          Type  sourceType           public cEventSuppressor Control control                if  control    null                  throw new ArgumentNullException  control    An instance of a control must be provided                   source   control               sourceType    source GetType                 sourceEventsInfo    sourceType GetProperty  Events   BindingFlags Instance   BindingFlags NonPublic                sourceEventHandlerList    EventHandlerList  sourceEventsInfo GetValue  source  null                eventHandlerListType    sourceEventHandlerList GetType                 headFI    eventHandlerListType GetField  head   BindingFlags Instance   BindingFlags NonPublic                     private Dictionary lt object  Delegate   gt  BuildList                 Dictionary lt object  Delegate   gt  retval   new Dictionary lt object  Delegate   gt                 object head    headFI GetValue  sourceEventHandlerList               if  head    null                    Type listEntryType   head GetType                    FieldInfo delegateFI   listEntryType GetField  handler   BindingFlags Instance   BindingFlags NonPublic                   FieldInfo keyFI   listEntryType GetField  key   BindingFlags Instance   BindingFlags NonPublic                   FieldInfo nextFI   listEntryType GetField  next   BindingFlags Instance   BindingFlags NonPublic                   retval   BuildListWalk retval  head  delegateFI  keyFI  nextFI                             return retval                     private Dictionary lt object  Delegate   gt  BuildListWalk Dictionary lt object  Delegate   gt  dict                                      object entry  FieldInfo delegateFI  FieldInfo keyFI  FieldInfo nextFI                if  entry    null                    Delegate dele    Delegate delegateFI GetValue entry                   object key   keyFI GetValue entry                   object next   nextFI GetValue entry                    if  dele    null                        Delegate   listeners   dele GetInvocationList                        if  listeners    null  amp  amp  listeners Length  gt  0                            dict Add key  listeners                                                           if  next    null                        dict   BuildListWalk dict  next  delegateFI  keyFI  nextFI                                               return dict                    public void Resume                       public void Resume string pMethodName                  if   handlers    null                    throw new ApplicationException  Events have not been suppressed                 Dictionary lt object  Delegate   gt  toRemove   new Dictionary lt object  Delegate   gt                     goes through all handlers which have been suppressed   If we are resuming                 all handlers  or if we find the matching handler  add it back to the                control s event handlers             foreach  KeyValuePair lt object  Delegate   gt  pair in suppressedHandlers                     for  int x   0  x  lt  pair Value Length  x                           string methodName   pair Value x  Method Name                      if  pMethodName    null    methodName Equals pMethodName                              sourceEventHandlerList AddHandler pair Key  pair Value x                            toRemove Add pair Key  pair Value                                                                        remove all un-suppressed handlers from the list of suppressed handlers             foreach  KeyValuePair lt object  Delegate   gt  pair in toRemove                    for  int x   0  x  lt  pair Value Length  x                          suppressedHandlers Remove pair Key                                                  handlers   null                    public void Suppress                 Suppress null                     public void Suppress string pMethodName                  if   handlers    null                    throw new ApplicationException  Events are already being suppressed                  Dictionary lt object  Delegate   gt  dict   BuildList                 foreach  KeyValuePair lt object  Delegate   gt  pair in dict                    for  int x   pair Value Length - 1  x  gt   0  x--                          MethodInfo mi   pair Value x  Method                        string s1   mi Name     name of the method                       object o   pair Value x  Target                         can use this to invoke method    pair Value x  DynamicInvoke                     string methodName   pair Value x  Method Name                       if  pMethodName    null    methodName Equals pMethodName                              sourceEventHandlerList RemoveHandler pair Key  pair Value x                            suppressedHandlers Add pair Key  pair Value

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This is not an answer to the OP  but I thought I d post this here in case it can help others           lt summary gt        Method to remove a  single  SocketAsyncEventArgs Completed event handler  This is        partially based on information found here  http   stackoverflow com a 91853 253938              But note that this may not be a good idea  being very  Net implementation-dependent  Note        in particular use of  m Completed  instead of  Completed          lt  summary gt    private static void RemoveCompletedEventHandler SocketAsyncEventArgs eventArgs           FieldInfo fieldInfo   typeof SocketAsyncEventArgs  GetField  m Completed                                                    BindingFlags Instance   BindingFlags NonPublic        eventArgs Completed -   EventHandler lt SocketAsyncEventArgs gt  fieldInfo GetValue eventArgs

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Sometimes we have to work with ThirdParty controls and we need to build these awkward solutions  Based in  Anoop Muraleedharan answer I created this solution with inference type and ToolStripItem support      public static void RemoveItemEvents lt T gt  this T target  string eventName           where T   ToolStripItem                           RemoveObjectEvents lt T gt  target  eventName              public static void RemoveControlEvents lt T gt  this T target  string eventName          where T   Control               RemoveObjectEvents lt T gt  target  eventName              private static void RemoveObjectEvents lt T gt  T target  string Event  where T   class               var typeOfT   typeof T           var fieldInfo   typeOfT BaseType GetField              Event  BindingFlags Static   BindingFlags NonPublic           var provertyValue   fieldInfo GetValue target           var propertyInfo   typeOfT GetProperty               Events   BindingFlags NonPublic   BindingFlags Instance           var eventHandlerList    EventHandlerList propertyInfo GetValue target  null           eventHandlerList RemoveHandler provertyValue  eventHandlerList provertyValue            And you can use it like this      var toolStripButton   new ToolStripButton        toolStripButton RemoveItemEvents  EventClick         var button   new Button        button RemoveControlEvents  EventClick

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I found a solution on the MSDN forums  The sample code below will remove all Click events from button1  public partial class Form1   Form       public Form1                 InitializeComponent             button1 Click    button1 Click          button1 Click    button1 Click2          button2 Click    button2 Click             private void button1 Click object sender  EventArgs e     gt  MessageBox Show  quot Hello quot        private void button1 Click2 object sender  EventArgs e    gt  MessageBox Show  quot World quot        private void button2 Click object sender  EventArgs e     gt  RemoveClickEvent button1        private void RemoveClickEvent Button b                FieldInfo f1   typeof Control  GetField  quot EventClick quot                BindingFlags Static   BindingFlags NonPublic            object obj   f1 GetValue b           PropertyInfo pi   b GetType   GetProperty  quot Events quot                 BindingFlags NonPublic   BindingFlags Instance            EventHandlerList list    EventHandlerList pi GetValue b  null           list RemoveHandler obj  list obj

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It doesn t do any harm to delete a non-existing event handler  So if you know what handlers there might be  you can simply delete all of them  I just had similar case  This may help in some cases   Like      Add handlers    if  something        c Click    DoesSomething    else       c Click    DoesSomethingElse        Remove handlers    c Click -  DoesSomething  c Click -  DoesSomethingElse

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removes all handlers for button    save RemoveEvents                     public static class EventExtension       public static void RemoveEvents lt T gt  this T target  where T   Control              var propInfo   typeof T  GetProperty  Events   BindingFlags NonPublic   BindingFlags Instance           var list    EventHandlerList propInfo GetValue target  null           list Dispose

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You guys are making this WAY too hard on yourselves  It s this easy   void OnFormClosing object sender  FormClosingEventArgs e        foreach Delegate d in FindClicked GetInvocationList                  FindClicked -   FindClickedHandler d

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Well  here there s another solution to remove an asociated event  if you already have a method for handling the events for the control    EventDescriptor ed   TypeDescriptor GetEvents this button1  Find  MouseDown  true               Delegate delegate   Delegate CreateDelegate typeof EventHandler   this   button1 MouseDownClicked    if ed  null       ed RemoveEventHandler this button1  delegate

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If you reaallly have to do this    it ll take reflection and quite some time to do this  Event handlers are managed in an event-to-delegate-map inside a control  You would need to   Reflect and obtain this map in the control instance  Iterate for each event  get the delegate   each delegate in turn could be a chained series of event handlers  So call obControl RemoveHandler event  handler     In short  a lot of work  It is possible in theory    I never tried something like this   See if you can have better control discipline over the subscribe-unsubscribe phase for the control

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I hated any complete solutions shown here  I did a mix and tested now  worked for any event handler   public class MyMain       public void MyMethod             AnotherClass TheEventHandler    DoSomeThing             private void DoSomething object sender  EventArgs e            Debug WriteLine  I did something            AnotherClass ClearAllDelegatesOfTheEventHandler              public static class AnotherClass        public static event EventHandler TheEventHandler       public static void ClearAllDelegatesOfTheEventHandler              foreach  Delegate d in TheEventHandler GetInvocationList                          TheEventHandler -   EventHandler d                      Easy  Thanks for Stephen Punak   I used it because I use a generic local method to remove the delegates and the local method was called after different cases  when different delegates are setted

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Sometimes we have to work with ThirdParty controls and we need to build these awkward solutions  Based in  Anoop Muraleedharan answer I created this solution with inference type and ToolStripItem support      public static void RemoveItemEvents lt T gt  this T target  string eventName           where T   ToolStripItem                           RemoveObjectEvents lt T gt  target  eventName              public static void RemoveControlEvents lt T gt  this T target  string eventName          where T   Control               RemoveObjectEvents lt T gt  target  eventName              private static void RemoveObjectEvents lt T gt  T target  string Event  where T   class               var typeOfT   typeof T           var fieldInfo   typeOfT BaseType GetField              Event  BindingFlags Static   BindingFlags NonPublic           var provertyValue   fieldInfo GetValue target           var propertyInfo   typeOfT GetProperty               Events   BindingFlags NonPublic   BindingFlags Instance           var eventHandlerList    EventHandlerList propertyInfo GetValue target  null           eventHandlerList RemoveHandler provertyValue  eventHandlerList provertyValue            And you can use it like this      var toolStripButton   new ToolStripButton        toolStripButton RemoveItemEvents  EventClick         var button   new Button        button RemoveControlEvents  EventClick

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I m actually using this method and it works perfectly  I was  inspired  by the code written by Aeonhack here   Public Event MyEvent   Protected Overrides Sub Dispose ByVal disposing As Boolean      If MyEventEvent IsNot Nothing Then         For Each d In MyEventEvent GetInvocationList   If this throws an exception  try using  ToArray             RemoveHandler MyEvent  d         Next     End If End Sub   The field MyEventEvent is hidden  but it does exist   Debugging  you can see how d target is the object actually handling the event  and d method its method  You only have to remove it   It works great  No more objects not being GC ed because of the event handlers

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You guys are making this WAY too hard on yourselves  It s this easy   void OnFormClosing object sender  FormClosingEventArgs e        foreach Delegate d in FindClicked GetInvocationList                  FindClicked -   FindClickedHandler d

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Stephen has right  It is very easy   public event EventHandler lt Cles graph doivent etre redessines gt  les graph doivent etre redessines  public void remove event         if  this les graph doivent etre redessines    null                foreach  EventHandler lt Cles graph doivent etre redessines gt  F les graph doivent etre redessines in this les graph doivent etre redessines GetInvocationList                          this les graph doivent etre redessines -  F les graph doivent etre redessines

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I just found How to suspend events when setting a property of a WinForms control  It will remove all events from a control   namespace CMessWin05       public class EventSuppressor               Control  source          EventHandlerList  sourceEventHandlerList          FieldInfo  headFI          Dictionary lt object  Delegate   gt   handlers          PropertyInfo  sourceEventsInfo          Type  eventHandlerListType          Type  sourceType            public EventSuppressor Control control                        if  control    null                  throw new ArgumentNullException  control    An instance of a control must be provided                   source   control               sourceType    source GetType                 sourceEventsInfo    sourceType GetProperty  Events   BindingFlags Instance   BindingFlags NonPublic                sourceEventHandlerList    EventHandlerList  sourceEventsInfo GetValue  source  null                eventHandlerListType    sourceEventHandlerList GetType                 headFI    eventHandlerListType GetField  head   BindingFlags Instance   BindingFlags NonPublic                      private void BuildList                          handlers   new Dictionary lt object  Delegate   gt                 object head    headFI GetValue  sourceEventHandlerList               if  head    null                                Type listEntryType   head GetType                    FieldInfo delegateFI   listEntryType GetField  handler   BindingFlags Instance   BindingFlags NonPublic                   FieldInfo keyFI   listEntryType GetField  key   BindingFlags Instance   BindingFlags NonPublic                   FieldInfo nextFI   listEntryType GetField  next   BindingFlags Instance   BindingFlags NonPublic                   BuildListWalk head  delegateFI  keyFI  nextFI                                    private void BuildListWalk object entry  FieldInfo delegateFI  FieldInfo keyFI  FieldInfo nextFI                        if  entry    null                                Delegate dele    Delegate delegateFI GetValue entry                   object key   keyFI GetValue entry                   object next   nextFI GetValue entry                    Delegate   listeners   dele GetInvocationList                    if listeners    null  amp  amp  listeners Length  gt  0                       handlers Add key  listeners                    if  next    null                                        BuildListWalk next  delegateFI  keyFI  nextFI                                                      public void Resume                         if   handlers    null                  throw new ApplicationException  Events have not been suppressed                  foreach  KeyValuePair lt object  Delegate   gt  pair in  handlers                                for  int x   0  x  lt  pair Value Length  x                         sourceEventHandlerList AddHandler pair Key  pair Value x                                handlers   null                     public void Suppress                         if   handlers    null                  throw new ApplicationException  Events are already being suppressed                  BuildList                 foreach  KeyValuePair lt object  Delegate   gt  pair in  handlers                                for  int x   pair Value Length - 1  x  gt   0  x--                       sourceEventHandlerList RemoveHandler pair Key  pair Value x

[c#] How to remove all event handlers from an event

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