How to know user has clicked X or the Close button

Question

In MSDN I found CloseReason UserClosing to know that the user had decided to close the form but I guess it is the same for both clicking the X button or clicking the close button  So how can I differentiate between these two in my code   Thanks all

User · Answer

It determines when to close the application if a form is closed  if your application is not attached to a specific form        private void MyForm FormClosed object sender  FormClosedEventArgs e                if  Application OpenForms Count    0  Application Exit

User · Answer

How to detect if the form closed by click on X button or by calling Close   in code  You cannot rely on close reason of the form closing event args  because if the user click X button on title bar or close the form using Alt   F4 or use system menu to close the form or the form get closed by calling Close   method  all all above cases  the close reason will be Closed by User which is not desired result  To distinguish if the form closed by X button or by Close method  you can use either of the following options   Handle WM SYSCOMMAND and check for SC CLOSE and set a flag  Check the StackTrace to see if any of the frames contain Close method call   Example 1 - Handle WM SYSCOMMAND public bool ClosedByXButtonOrAltF4  get  private set   private const int SC CLOSE   0xF060  private const int WM SYSCOMMAND   0x0112  protected override void WndProc ref Message msg        if  msg Msg    WM SYSCOMMAND  amp  amp  msg WParam ToInt32      SC CLOSE          ClosedByXButtonOrAltF4   true      base WndProc ref msg     protected override void OnShown EventArgs e        ClosedByXButtonOrAltF4   false       protected override void OnFormClosing FormClosingEventArgs e        if  ClosedByXButtonOrAltF4          MessageBox Show  quot Closed by X or Alt F4 quot        else         MessageBox Show  quot Closed by calling Close   quot       Example 2 - Checking StackTrace protected override void OnFormClosing FormClosingEventArgs e        if  new StackTrace   GetFrames   Any x   gt  x GetMethod   Name     quot Close quot            MessageBox Show  quot Closed by calling Close   quot        else         MessageBox Show  quot Closed by X or Alt F4 quot

User · Answer

Assuming you re asking for WinForms  you may use the FormClosing   event  The event FormClosing   is triggered any time a form is to get closed   To detect if the user clicked either X or your CloseButton  you may get it through the sender object  Try to cast sender as a Button control  and verify perhaps for its name  CloseButton   for instance   private void Form1 FormClosing object sender  FormClosingEventArgs e        if  string Equals  sender as Button  Name    CloseButton               Do something proper to CloseButton      else            Then assume that X has been clicked and act accordingly      Otherwise  I have never ever needed to differentiate whether X or CloseButton was clicked  as I wanted to perform something specific on the FormClosing event  like closing all MdiChildren before closing the MDIContainerForm  or event checking for unsaved changes  Under these circumstances  we don t need  according to me  to differentiate from either buttons   Closing by ALT F4 will also trigger the FormClosing   event  as it sends a message to the Form that says to close  You may cancel the event by setting the   FormClosingEventArgs Cancel   true     In our example  this would translate to be   e Cancel   true    Notice the difference between the FormClosing   and the FormClosed   events    FormClosing occurs when the form received the message to be closed  and verify whether it has something to do before it is closed   FormClosed occurs when the form is actually closed  so after it is closed   Does this help

User · Answer

I ve done something like this  private void Form FormClosing object sender  FormClosingEventArgs e                if   sender as Form  ActiveControl is Button                          CloseButton                   else                         The X has been clicked

User · Answer

You can try adding event handler from design like this  Open form in design view  open properties window or press F4  click event toolbar button to view events on Form object  find FormClosing event in Behavior group  and double click it  Reference  https   social msdn microsoft com Forums vstudio en-US 9bdee708-db4b-4e46-a99c-99726fa25cfb how-do-i-add-formclosing-event forum csharpgeneral

User · Answer

if  this DialogResult    DialogResult Cancel                               else                       switch  e CloseReason                                case CloseReason UserClosing                      e Cancel   true                      break                            if condition will execute when user clicks  X  or close button on form  The else can be used when user clicks Alt f4 for any other purpose

User · Answer

namespace Test       public partial class Member   Form               public Member                         InitializeComponent                       private bool xClicked   true           private void btnClose Click object sender  EventArgs e                        xClicked   false              Close                       private void Member FormClosing object sender  FormClosingEventArgs e                        if  xClicked                                   user click the X                            else                                   user click the close button

User · Answer

I always use a Form Close method in my applications that catches alt   x from my exit Button  alt   f4 or another form closing event was initiated  All my classes have the class name defined as Private string mstrClsTitle    grmRexcel  in this case  an Exit method that calls the Form Closing Method and a Form Closing Method  I also have a statement for the Form Closing Method - this FormClosing   My Form Closing Form Closing method name    The code for this   namespace Rexcel II       public partial class frmRexcel   Form               private string mstrClsTitle    frmRexcel            public frmRexcel                         InitializeComponent                 this FormClosing    frmRexcel FormClosing                          lt summary gt              Handles the Button Exit Event executed by the Exit Button Click             or Alt   x                           lt  summary gt               lt param name  sender  gt  lt  param gt               lt param name  e  gt  lt  param gt          private void btnExit Click object sender  EventArgs e                                    this Close                                     lt summary gt              Handles the Form Closing event                           lt  summary gt               lt param name  sender  gt  lt  param gt               lt param name  e  gt  lt  param gt          private void frmRexcel FormClosing object sender  FormClosingEventArgs e                            ---- If windows is shutting down                  ---- I don t want to hold up the process             if  e CloseReason    CloseReason WindowsShutDown  return                                    ---- Ok  Windows is not shutting down so                    ---- either btnExit or Alt   x or Alt   f4 has been clicked or                    ---- another form closing event was intiated                             Confirm user wants to close the application                 switch  MessageBox Show this                                        Are you sure you want to close the Application                                        mstrClsTitle     frmRexcel FormClosing                                       MessageBoxButtons YesNo  MessageBoxIcon Question                                             ----     if No keep the application alive                        ----      else close the application                     case DialogResult No                          e Cancel   true                          break                      default                          break

User · Answer

The  X  button registers as DialogResult Cancel so another option is to evaluate the DialogResult    If you have multiple buttons on your form  you re probably already associating different DialogResults to each and this will provide you with the means to tell the difference between each button     Example  btnSubmit DialogResult   DialogResult OK  btnClose DialogResult   Dialogresult Abort        public Form1                 InitializeComponent             this FormClosing    Form1 FormClosing                  lt summary gt          Override the Close Form event         Do something          lt  summary gt           lt param name  sender  gt  lt  param gt           lt param name  e  gt  lt  param gt      private void Form1 FormClosing Object sender  FormClosingEventArgs e                  In case windows is trying to shut down  don t hold the process up         if  e CloseReason    CloseReason WindowsShutDown  return           if  this DialogResult    DialogResult Cancel                           Assume that X has been clicked and act accordingly                 Confirm user wants to close             switch  MessageBox Show this   Are you sure     Do you still want         MessageBoxButtons YesNo  MessageBoxIcon Question                                   Stay on this form                 case DialogResult No                      e Cancel   true                      break                  default                      break

User · Answer

I agree with the DialogResult-Solution as the more straight forward one   In VB NET however  typecast is required to get the CloseReason-Property      Private Sub MyForm Closing sender As Object  e As CancelEventArgs  Handles Me Closing          Dim eCast As System Windows Forms FormClosingEventArgs         eCast   TryCast e  System Windows Forms FormClosingEventArgs          If eCast CloseReason   Windows Forms CloseReason None Then             MsgBox  Button Pressed           Else             MsgBox  ALT F4 or  x  or other reason           End If      End Sub

User · Answer

The CloseReason enumeration you found on MSDN is just for the purpose of checking whether the user closed the app  or it was due to a shutdown  or closed by the task manager  etc     You can do different actions  according to the reason  like   void Form FormClosing object sender  FormClosingEventArgs e        if e CloseReason    CloseReason UserClosing             Prompt user to save his data      if e CloseReason    CloseReason WindowsShutDown             Autosave and clear up ressources     But like you guessed  there is no difference between clicking the x button  or rightclicking the taskbar and clicking  close   or pressing Alt F4  etc  It all ends up in a CloseReason UserClosing reason

User · Answer

I also had to register the closing function inside the form s  InitializeComponent    method   private void InitializeComponent            this FormClosing    FrmMain FormClosing             My  FormClosing  function looks similar to the given answer  https   stackoverflow com a 2683846 3323790    private void FrmMain FormClosing object sender  FormClosingEventArgs e        if  e CloseReason    CloseReason UserClosing           MessageBox Show  Closed by User    UserClosing               if  e CloseReason    CloseReason WindowsShutDown           MessageBox Show  Closed by Windows shutdown    WindowsShutDown              One more thing to mention  There is also a  FormClosed  function which occurs after  FormClosing   To use this function  register it as shown below   this FormClosed    MainPage FormClosed   private void MainPage FormClosing object sender  FormClosingEventArgs e       your code after the form is closed

[c#] How to know user has clicked "X" or the "Close" button?

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