WPF User Control Parent

Question

I have a user control that I load into a MainWindow at runtime  I cannot get a handle on the containing window from the UserControl    I have tried this Parent  but it s always null  Does anyone know how to get a handle to the containing window from a user control in WPF   Here is how the control is loaded   private void XMLLogViewer MenuItem Click object sender  RoutedEventArgs e        MenuItem application   sender as MenuItem      string parameter   application CommandParameter as string      string controlName   parameter      if  uxPanel Children Count    0                System Runtime Remoting ObjectHandle instance   Activator CreateInstance Assembly GetExecutingAssembly   FullName  controlName           UserControl control   instance Unwrap   as UserControl          this LoadControl control            private void LoadControl UserControl control        if  uxPanel Children Count  gt  0                foreach  UIElement ctrl in uxPanel Children                        if  ctrl GetType      control GetType                                  this SetControl control                                     else               this SetControl control            private void SetControl UserControl control        control Width   uxPanel Width      control Height   uxPanel Height      uxPanel Children Add control

User · Answer

I ve found that the parent of a UserControl is always null in the constructor  but in any event handlers the parent is set correctly  I guess it must have something to do with the way the control tree is loaded  So to get around this you can just get the parent in the controls Loaded event    For an example checkout this question WPF User Control  39 s DataContext is Null

User · Answer

Try using the following   Window parentWindow   Window GetWindow userControlReference     The GetWindow method will walk the VisualTree for you and locate the window that is hosting your control   You should run this code after the control has loaded  and not in the Window constructor  to prevent the GetWindow method from returning null  E g  wire up an event    this Loaded    new RoutedEventHandler UserControl Loaded

User · Answer

If you just want to get a specific parent  not only the window  a specific parent in the tree structure  and also not using recursion  or hard break loop counters  you can use the following  public static T FindParent lt T gt  DependencyObject current      where T   class        var dependency   current       while  dependency   VisualTreeHelper GetParent dependency     LogicalTreeHelper GetParent dependency      null          amp  amp    dependency is T            return dependency as T     Just don t put this call in a constructor  since the Parent property is not yet initialized   Add it in the loading event handler  or in other parts of your application

User · Answer

I ve found that the parent of a UserControl is always null in the constructor  but in any event handlers the parent is set correctly  I guess it must have something to do with the way the control tree is loaded  So to get around this you can just get the parent in the controls Loaded event    For an example checkout this question WPF User Control  39 s DataContext is Null

User · Answer

DependencyObject GetTopParent DependencyObject current        while  VisualTreeHelper GetParent current     null                current   VisualTreeHelper GetParent current             return current     DependencyObject parent   GetTopParent thisUserControl

User · Answer

This approach worked for me but it is not as specific as your question   App Current MainWindow

User · Answer

Try using the following   Window parentWindow   Window GetWindow userControlReference     The GetWindow method will walk the VisualTree for you and locate the window that is hosting your control   You should run this code after the control has loaded  and not in the Window constructor  to prevent the GetWindow method from returning null  E g  wire up an event    this Loaded    new RoutedEventHandler UserControl Loaded

User · Answer

If you are finding this question and the VisualTreeHelper isn t working for you or working sporadically  you may need to include LogicalTreeHelper in your algorithm   Here is what I am using   public static T TryFindParent lt T gt  DependencyObject current  where T   class       DependencyObject parent   VisualTreeHelper GetParent current       if  parent    null           parent   LogicalTreeHelper GetParent current       if  parent    null           return null       if  parent is T           return parent as T      else         return TryFindParent lt T gt  parent

User · Answer

I needed to use the Window GetWindow this  method within Loaded event handler  In other words  I used both Ian Oakes  answer in combination with Alex s answer to get a user control s parent   public MainView         InitializeComponent         this Loaded    new RoutedEventHandler MainView Loaded      void MainView Loaded object sender  RoutedEventArgs e        Window parentWindow   Window GetWindow this

User · Answer

Try using the following   Window parentWindow   Window GetWindow userControlReference     The GetWindow method will walk the VisualTree for you and locate the window that is hosting your control   You should run this code after the control has loaded  and not in the Window constructor  to prevent the GetWindow method from returning null  E g  wire up an event    this Loaded    new RoutedEventHandler UserControl Loaded

User · Answer

I ve found that the parent of a UserControl is always null in the constructor  but in any event handlers the parent is set correctly  I guess it must have something to do with the way the control tree is loaded  So to get around this you can just get the parent in the controls Loaded event    For an example checkout this question WPF User Control  39 s DataContext is Null

User · Answer

If you are finding this question and the VisualTreeHelper isn t working for you or working sporadically  you may need to include LogicalTreeHelper in your algorithm   Here is what I am using   public static T TryFindParent lt T gt  DependencyObject current  where T   class       DependencyObject parent   VisualTreeHelper GetParent current       if  parent    null           parent   LogicalTreeHelper GetParent current       if  parent    null           return null       if  parent is T           return parent as T      else         return TryFindParent lt T gt  parent

User · Answer

DependencyObject parent   ExVisualTreeHelper FindVisualParent lt UserControl gt  this

User · Answer

Use VisualTreeHelper GetParent or the recursive function below to find the parent window  public static Window FindParentWindow DependencyObject child        DependencyObject parent  VisualTreeHelper GetParent child          CHeck if this is the end of the tree     if  parent    null  return null       Window parentWindow   parent as Window      if  parentWindow    null                return parentWindow            else                 use recursion until it reaches a Window         return FindParentWindow parent

User · Answer

Another way   var main   App Current MainWindow as MainWindow

User · Answer

I ve found that the parent of a UserControl is always null in the constructor  but in any event handlers the parent is set correctly  I guess it must have something to do with the way the control tree is loaded  So to get around this you can just get the parent in the controls Loaded event    For an example checkout this question WPF User Control  39 s DataContext is Null

User · Answer

How about this   DependencyObject parent   ExVisualTreeHelper FindVisualParent lt UserControl gt  this    public static class ExVisualTreeHelper            lt summary gt          Finds the visual parent           lt  summary gt           lt typeparam name  T  gt  lt  typeparam gt           lt param name  sender  gt The sender  lt  param gt           lt returns gt  lt  returns gt      public static T FindVisualParent lt T gt  DependencyObject sender  where T   DependencyObject               if  sender    null                        return  null                     else if  VisualTreeHelper GetParent sender  is T                        return  VisualTreeHelper GetParent sender  as T                     else                       DependencyObject parent   VisualTreeHelper GetParent sender               return  FindVisualParent lt T gt  parent

User · Answer

I needed to use the Window GetWindow this  method within Loaded event handler  In other words  I used both Ian Oakes  answer in combination with Alex s answer to get a user control s parent   public MainView         InitializeComponent         this Loaded    new RoutedEventHandler MainView Loaded      void MainView Loaded object sender  RoutedEventArgs e        Window parentWindow   Window GetWindow this

User · Answer

This didn t work for me  as it went too far up the tree  and got the absolute root window for the entire application   Window parentWindow   Window GetWindow userControlReference     However  this worked to get the immediate window   DependencyObject parent   uiElement  int avoidInfiniteLoop   0  while   parent is Window   false        parent   VisualTreeHelper GetParent parent       avoidInfiniteLoop        if  avoidInfiniteLoop    1000                   Something is wrong - we could not find the parent window          break          Window window   parent as Window  window DragMove

User · Answer

DependencyObject parent   ExVisualTreeHelper FindVisualParent lt UserControl gt  this

User · Answer

Use VisualTreeHelper GetParent or the recursive function below to find the parent window  public static Window FindParentWindow DependencyObject child        DependencyObject parent  VisualTreeHelper GetParent child          CHeck if this is the end of the tree     if  parent    null  return null       Window parentWindow   parent as Window      if  parentWindow    null                return parentWindow            else                 use recursion until it reaches a Window         return FindParentWindow parent

User · Answer

Different approaches and different strategies  In my case I could not find the window of my dialog either through using VisualTreeHelper or extension methods from Telerik to find parent of given type  Instead  I found my my dialog view which accepts custom injection of contents using Application Current Windows   public Window GetCurrentWindowOfType lt TWindowType gt      return Application Current Windows OfType lt TWindowType gt    FirstOrDefault   as Window

User · Answer

The Window GetWindow userControl  will return the actual window only after the window was initialized  InitializeComponent   method finished    This means  that if your user control is initialized together with its window  for instance you put your user control into the window s xaml file   then on the user control s OnInitialized event you will not get the window  it will be null   cause in that case the user control s OnInitialized event fires before the window is initialized   This also means that if your user control is initialized after its window  then you can get the window already in the user control s constructor

User · Answer

Another way   var main   App Current MainWindow as MainWindow

User · Answer

It s working for me   DependencyObject GetTopLevelControl DependencyObject control        DependencyObject tmp   control      DependencyObject parent   null      while  tmp   VisualTreeHelper GetParent tmp      null                parent   tmp            return parent

User · Answer

DependencyObject GetTopParent DependencyObject current        while  VisualTreeHelper GetParent current     null                current   VisualTreeHelper GetParent current             return current     DependencyObject parent   GetTopParent thisUserControl

User · Answer

It s working for me   DependencyObject GetTopLevelControl DependencyObject control        DependencyObject tmp   control      DependencyObject parent   null      while  tmp   VisualTreeHelper GetParent tmp      null                parent   tmp            return parent

User · Answer

The Window GetWindow userControl  will return the actual window only after the window was initialized  InitializeComponent   method finished    This means  that if your user control is initialized together with its window  for instance you put your user control into the window s xaml file   then on the user control s OnInitialized event you will not get the window  it will be null   cause in that case the user control s OnInitialized event fires before the window is initialized   This also means that if your user control is initialized after its window  then you can get the window already in the user control s constructor

User · Answer

If you just want to get a specific parent  not only the window  a specific parent in the tree structure  and also not using recursion  or hard break loop counters  you can use the following  public static T FindParent lt T gt  DependencyObject current      where T   class        var dependency   current       while  dependency   VisualTreeHelper GetParent dependency     LogicalTreeHelper GetParent dependency      null          amp  amp    dependency is T            return dependency as T     Just don t put this call in a constructor  since the Parent property is not yet initialized   Add it in the loading event handler  or in other parts of your application

User · Answer

This approach worked for me but it is not as specific as your question   App Current MainWindow

User · Answer

Gold plated edition of the above  I need a generic function which can infer a Window within the context of a MarkupExtension -  public sealed class MyExtension   MarkupExtension       public override object ProvideValue IServiceProvider serviceProvider    gt          new MyWrapper ResolveRootObject serviceProvider        object ResolveRootObject IServiceProvider serviceProvider    gt            GetService lt IRootObjectProvider gt  serviceProvider  RootObject     class MyWrapper       object  rootObject       Window OwnerWindow     gt  WindowFromRootObject  rootObject        static Window WindowFromRootObject object root    gt           root as Window     VisualParent lt Window gt   DependencyObject root       static T VisualParent lt T gt  DependencyObject node  where T   class               if  node    null              throw new InvalidOperationException  Could not locate a parent     typeof T  Name           var target   node as T          if  target    null              return target          return VisualParent lt T gt  VisualTreeHelper GetParent node              MyWrapper Owner   will correctly infer a Window on the following basis    the root Window by walking the visual tree  if used in the context of a UserControl  the window within which it is used  if it is used in the context of a Window s markup

User · Answer

Use VisualTreeHelper GetParent or the recursive function below to find the parent window  public static Window FindParentWindow DependencyObject child        DependencyObject parent  VisualTreeHelper GetParent child          CHeck if this is the end of the tree     if  parent    null  return null       Window parentWindow   parent as Window      if  parentWindow    null                return parentWindow            else                 use recursion until it reaches a Window         return FindParentWindow parent

User · Answer

This didn t work for me  as it went too far up the tree  and got the absolute root window for the entire application   Window parentWindow   Window GetWindow userControlReference     However  this worked to get the immediate window   DependencyObject parent   uiElement  int avoidInfiniteLoop   0  while   parent is Window   false        parent   VisualTreeHelper GetParent parent       avoidInfiniteLoop        if  avoidInfiniteLoop    1000                   Something is wrong - we could not find the parent window          break          Window window   parent as Window  window DragMove

User · Answer

How about this   DependencyObject parent   ExVisualTreeHelper FindVisualParent lt UserControl gt  this    public static class ExVisualTreeHelper            lt summary gt          Finds the visual parent           lt  summary gt           lt typeparam name  T  gt  lt  typeparam gt           lt param name  sender  gt The sender  lt  param gt           lt returns gt  lt  returns gt      public static T FindVisualParent lt T gt  DependencyObject sender  where T   DependencyObject               if  sender    null                        return  null                     else if  VisualTreeHelper GetParent sender  is T                        return  VisualTreeHelper GetParent sender  as T                     else                       DependencyObject parent   VisualTreeHelper GetParent sender               return  FindVisualParent lt T gt  parent

User · Answer

Different approaches and different strategies  In my case I could not find the window of my dialog either through using VisualTreeHelper or extension methods from Telerik to find parent of given type  Instead  I found my my dialog view which accepts custom injection of contents using Application Current Windows   public Window GetCurrentWindowOfType lt TWindowType gt      return Application Current Windows OfType lt TWindowType gt    FirstOrDefault   as Window

User · Answer

Use VisualTreeHelper GetParent or the recursive function below to find the parent window  public static Window FindParentWindow DependencyObject child        DependencyObject parent  VisualTreeHelper GetParent child          CHeck if this is the end of the tree     if  parent    null  return null       Window parentWindow   parent as Window      if  parentWindow    null                return parentWindow            else                 use recursion until it reaches a Window         return FindParentWindow parent

User · Answer

Gold plated edition of the above  I need a generic function which can infer a Window within the context of a MarkupExtension -  public sealed class MyExtension   MarkupExtension       public override object ProvideValue IServiceProvider serviceProvider    gt          new MyWrapper ResolveRootObject serviceProvider        object ResolveRootObject IServiceProvider serviceProvider    gt            GetService lt IRootObjectProvider gt  serviceProvider  RootObject     class MyWrapper       object  rootObject       Window OwnerWindow     gt  WindowFromRootObject  rootObject        static Window WindowFromRootObject object root    gt           root as Window     VisualParent lt Window gt   DependencyObject root       static T VisualParent lt T gt  DependencyObject node  where T   class               if  node    null              throw new InvalidOperationException  Could not locate a parent     typeof T  Name           var target   node as T          if  target    null              return target          return VisualParent lt T gt  VisualTreeHelper GetParent node              MyWrapper Owner   will correctly infer a Window on the following basis    the root Window by walking the visual tree  if used in the context of a UserControl  the window within which it is used  if it is used in the context of a Window s markup

User · Answer

I ll add my experience  Although using the Loaded event can do the job  I think it may be more suitable to override the OnInitialized method  Loaded occurs after the window is first displayed  OnInitialized gives you chance to make any changes  for example  add controls to the window before it is rendered

User · Answer

I ll add my experience  Although using the Loaded event can do the job  I think it may be more suitable to override the OnInitialized method  Loaded occurs after the window is first displayed  OnInitialized gives you chance to make any changes  for example  add controls to the window before it is rendered

User · Answer

Try using the following   Window parentWindow   Window GetWindow userControlReference     The GetWindow method will walk the VisualTree for you and locate the window that is hosting your control   You should run this code after the control has loaded  and not in the Window constructor  to prevent the GetWindow method from returning null  E g  wire up an event    this Loaded    new RoutedEventHandler UserControl Loaded

[c#] WPF User Control Parent

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