How can I find WPF controls by name or type

Question

I need to search a WPF control hierarchy for controls that match a given name or type  How can I do this

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Whilst I love recursion in general  it s not as efficient as iteration when programming in C   so perhaps the following solution is neater than the one suggested by John Myczek  This searches up a hierarchy from a given control to find an ancestor control of a particular type   public static T FindVisualAncestorOfType lt T gt  this DependencyObject Elt      where T   DependencyObject       for  DependencyObject parent   VisualTreeHelper GetParent Elt           parent    null  parent   VisualTreeHelper GetParent parent                 T result   parent as T          if  result    null              return result            return null      Call it like this to find the Window containing a control called ExampleTextBox   Window window   ExampleTextBox FindVisualAncestorOfType lt Window gt

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These options already talk about traversing the Visual Tree in C    Its possible to traverse the visual tree in xaml as well using RelativeSource markup extension  msdn  find by type  Binding   Binding RelativeSource  RelativeSource Mode FindAncestor  AncestorType  x Type  lt TypeToFind gt

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This code just fixes  CrimsonX answer s bug    public static T FindChild lt T gt  DependencyObject parent  string childName         where T   DependencyObject                    Confirm parent and childName are valid         if  parent    null  return null         T foundChild   null         int childrenCount   VisualTreeHelper GetChildrenCount parent         for  int i   0  i  lt  childrenCount  i                    var child   VisualTreeHelper GetChild parent  i              If the child is not of the request child type child         T childType   child as T          if  childType    null                         recursively drill down the tree           foundChild   FindChild lt T gt  child  childName                 If the child is found  break so we do not overwrite the found child             if  foundChild    null  break                    else if   string IsNullOrEmpty childName                       var frameworkElement   child as FrameworkElement               If the child s name is set for search           if  frameworkElement    null  amp  amp  frameworkElement Name    childName                             if the child s name is of the request name             foundChild    T child              break                   recursively drill down the tree           foundChild   FindChild lt T gt  child  childName                 If the child is found  break so we do not overwrite the found child             if  foundChild    null  break            else                        child element found            foundChild    T child            break                           return foundChild            You just need to continue calling the method recursively if types are matching but names don t  this happens when you pass FrameworkElement as T   otherwise it s gonna return null and that s wrong

User · Answer

You can also find an element by name using FrameworkElement FindName string    Given    lt UserControl     gt       lt TextBlock x Name  myTextBlock    gt   lt  UserControl gt    In the code-behind file  you could write   var myTextBlock    TextBlock this FindName  myTextBlock      Of course  because it s defined using x Name  you could just reference the generated field  but perhaps you want to look it up dynamically rather than statically   This approach is also available for templates  in which the named item appears multiple times  once per usage of the template

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You can use the VisualTreeHelper to find controls  Below is a method that uses the VisualTreeHelper to find a parent control of a specified type   You can use the VisualTreeHelper to find controls in other ways as well   public static class UIHelper           lt summary gt         Finds a parent of a given item on the visual tree          lt  summary gt          lt typeparam name  T  gt The type of the queried item  lt  typeparam gt          lt param name  child  gt A direct or indirect child of the queried item  lt  param gt          lt returns gt The first parent item that matches the submitted type parameter          If not matching item can be found  a null reference is being returned  lt  returns gt     public static T FindVisualParent lt T gt  DependencyObject child       where T   DependencyObject               get parent item       DependencyObject parentObject   VisualTreeHelper GetParent child             we   ve reached the end of the tree       if  parentObject    null  return null            check if the parent matches the type we   re looking for       T parent   parentObject as T        if  parent    null                   return parent                else                     use recursion to proceed with next level          return FindVisualParent lt T gt  parentObject                    Call it like this   Window owner   UIHelper FindVisualParent lt Window gt  myControl

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If you want to find ALL controls of a specific type  you might be interested in this snippet too      public static IEnumerable lt T gt  FindVisualChildren lt T gt  DependencyObject parent           where T   DependencyObject               int childrenCount   VisualTreeHelper GetChildrenCount parent           for  int i   0  i  lt  childrenCount  i                          var child   VisualTreeHelper GetChild parent  i                var childType   child as T              if  childType    null                                yield return  T child                             foreach  var other in FindVisualChildren lt T gt  child                                 yield return other

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To find an ancestor of a given type from code  you can use    CanBeNull  public static T FindAncestor lt T gt  DependencyObject d  where T   DependencyObject       while  true                d   VisualTreeHelper GetParent d            if  d    null              return null           var t   d as T           if  t    null              return t            This implementation uses iteration instead of recursion which can be slightly faster   If you re using C  7  this can be made slightly shorter    CanBeNull  public static T FindAncestor lt T gt  DependencyObject d  where T   DependencyObject       while  true                d   VisualTreeHelper GetParent d            if  d    null              return null           if  d is T t              return t

User · Answer

This will dismiss some elements - you should extend it like this in order to support a wider array of controls  For a brief discussion  have a look here        lt summary gt       Helper methods for UI-related tasks        lt  summary gt   public static class UIHelper            lt summary gt         Finds a parent of a given item on the visual tree          lt  summary gt          lt typeparam name  T  gt The type of the queried item  lt  typeparam gt          lt param name  child  gt A direct or indirect child of the        queried item  lt  param gt          lt returns gt The first parent item that matches the submitted        type parameter  If not matching item can be found  a null        reference is being returned  lt  returns gt     public static T TryFindParent lt T gt  DependencyObject child       where T   DependencyObject             get parent item      DependencyObject parentObject   GetParentObject child           we ve reached the end of the tree      if  parentObject    null  return null          check if the parent matches the type we re looking for      T parent   parentObject as T       if  parent    null                return parent              else                 use recursion to proceed with next level        return TryFindParent lt T gt  parentObject                        lt summary gt         This method is an alternative to WPF s         lt see cref  VisualTreeHelper GetParent   gt  method  which also        supports content elements  Do note  that for content element         this method falls back to the logical tree of the element          lt  summary gt          lt param name  child  gt The item to be processed  lt  param gt          lt returns gt The submitted item s parent  if available  Otherwise        null  lt  returns gt     public static DependencyObject GetParentObject DependencyObject child            if  child    null  return null       ContentElement contentElement   child as ContentElement        if  contentElement    null                DependencyObject parent   ContentOperations GetParent contentElement          if  parent    null  return parent          FrameworkContentElement fce   contentElement as FrameworkContentElement         return fce    null   fce Parent   null                 if it s not a ContentElement  rely on VisualTreeHelper      return VisualTreeHelper GetParent child

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I have a sequence function like this  which is completely general        public static IEnumerable lt T gt  SelectAllRecursively lt T gt  this IEnumerable lt T gt  items  Func lt T  IEnumerable lt T gt  gt  func                return  items    Enumerable Empty lt T gt     SelectMany o   gt  new     o   Concat SelectAllRecursively func o   func             Getting immediate children       public static IEnumerable lt DependencyObject gt  FindChildren this DependencyObject obj                return Enumerable Range 0  VisualTreeHelper GetChildrenCount obj                Select i   gt  VisualTreeHelper GetChild obj  i            Finding all children down the hiararchical tree       public static IEnumerable lt DependencyObject gt  FindAllChildren this DependencyObject obj                return obj FindChildren   SelectAllRecursively o   gt  o FindChildren             You can call this on the Window to get all controls   After you have the collection  you can use LINQ  i e  OfType  Where

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Here s my code to find controls by Type while controlling how deep we go into the hierarchy   maxDepth    0 means infinitely deep    public static class FrameworkElementExtension       public static object   FindControls          this FrameworkElement f  Type childType  int maxDepth                return RecursiveFindControls f  childType  1  maxDepth              private static object   RecursiveFindControls          object o  Type childType  int depth  int maxDepth   0                List lt object gt  list   new List lt object gt             var attrs   o GetType                GetCustomAttributes typeof ContentPropertyAttribute   true           if  attrs    null  amp  amp  attrs Length  gt  0                        string childrenProperty    attrs 0  as ContentPropertyAttribute  Name              foreach  var c in  IEnumerable o GetType                    GetProperty childrenProperty  GetValue o  null                                 if  c GetType   FullName    childType FullName                      list Add c                   if  maxDepth    0    depth  lt  maxDepth                      list AddRange RecursiveFindControls                          c  childType  depth   1  maxDepth                                    return list ToArray

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I edited CrimsonX s code as it was not working with superclass types   public static T FindChild lt T gt  DependencyObject depObj  string childName     where T   DependencyObject          Confirm obj is valid       if  depObj    null  return null          success case     if  depObj is T  amp  amp    FrameworkElement depObj  Name    childName          return depObj as T       for  int i   0  i  lt  VisualTreeHelper GetChildrenCount depObj   i                  DependencyObject child   VisualTreeHelper GetChild depObj  i              DFS         T obj   FindChild lt T gt  child  childName            if  obj    null              return obj             return null

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My extensions to the code    Added overloads to find one child by type  by type and criteria  predicate   find all children of type which meet the criteria the FindChildren method is an iterator in addition to being an extension method for DependencyObject FindChildren walks logical sub-trees also  See Josh Smith s post linked in the blog post    Source  https   code google com p gishu-util source browse  git 2FWPF 2FUtilities  Explanatory blog post   http   madcoderspeak blogspot com 2010 04 wpf-find-child-control-of-specific-type html

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I combined the template format used by John Myczek and Tri Q s algorithm above to create a findChild Algorithm that can be used on any parent  Keep in mind that recursively searching a tree downwards could be a lengthy process  I ve only spot-checked this on a WPF application  please comment on any errors you might find and I ll correct my code     WPF Snoop is a useful tool in looking at the visual tree - I d strongly recommend using it while testing or using this algorithm to check your work    There is a small error in Tri Q s Algorithm  After the child is found  if childrenCount is   1 and we iterate again we can overwrite the properly found child  Therefore I added a if  foundChild    null  break  into my code to deal with this condition         lt summary gt      Finds a Child of a given item in the visual tree        lt  summary gt       lt param name  parent  gt A direct parent of the queried item  lt  param gt       lt typeparam name  T  gt The type of the queried item  lt  typeparam gt       lt param name  childName  gt x Name or Name of child   lt  param gt       lt returns gt The first parent item that matches the submitted type parameter       If not matching item can be found       a null parent is being returned  lt  returns gt  public static T FindChild lt T gt  DependencyObject parent  string childName     where T   DependencyObject            Confirm parent and childName are valid     if  parent    null  return null     T foundChild   null     int childrenCount   VisualTreeHelper GetChildrenCount parent     for  int i   0  i  lt  childrenCount  i            var child   VisualTreeHelper GetChild parent  i          If the child is not of the request child type child     T childType   child as T      if  childType    null                 recursively drill down the tree       foundChild   FindChild lt T gt  child  childName             If the child is found  break so we do not overwrite the found child         if  foundChild    null  break            else if   string IsNullOrEmpty childName               var frameworkElement   child as FrameworkElement           If the child s name is set for search       if  frameworkElement    null  amp  amp  frameworkElement Name    childName                     if the child s name is of the request name         foundChild    T child          break                    else                child element found        foundChild    T child        break               return foundChild      Call it like this    TextBox foundTextBox       UIHelper FindChild lt TextBox gt  Application Current MainWindow   myTextBoxName      Note Application Current MainWindow can be any parent window

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I was able to find objects by name using below code  stkMultiChildControl   stkMulti FindChild lt StackPanel gt   quot stkMultiControl  quot    couter ToString

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Since the question is general enough that it might attract people looking for answers to very trivial cases  if you just want a child rather than a descendant  you can use Linq   private void ItemsControlItem Loaded object sender  RoutedEventArgs e        if  SomeCondition                  var children    sender as Panel  Children          var child    from Control child in children                  where child Name     NameTextBox                   select child  First            child Focus              or of course the obvious for loop iterating over Children

User · Answer

Here is a solution that uses a flexible predicate   public static DependencyObject FindChild DependencyObject parent  Func lt DependencyObject  bool gt  predicate        if  parent    null  return null       int childrenCount   VisualTreeHelper GetChildrenCount parent       for  int i   0  i  lt  childrenCount  i                  var child   VisualTreeHelper GetChild parent  i            if  predicate child                         return child                    else                       var foundChild   FindChild child  predicate               if  foundChild    null                  return foundChild                       return null      You can for example call it like this   var child   FindChild parent  child   gt        var textBlock   child as TextBlock      if  textBlock    null  amp  amp  textBlock Name     MyTextBlock           return true      else         return false     as TextBlock

User · Answer

exciton80    I was having a problem with your code not recursing through usercontrols   It was hitting the Grid root and throwing an error   I believe this fixes it for me   public static object   FindControls this FrameworkElement f  Type childType  int maxDepth        return RecursiveFindControls f  childType  1  maxDepth      private static object   RecursiveFindControls object o  Type childType  int depth  int maxDepth   0        List lt object gt  list   new List lt object gt         var attrs   o GetType   GetCustomAttributes typeof ContentPropertyAttribute   true       if  attrs    null  amp  amp  attrs Length  gt  0                string childrenProperty    attrs 0  as ContentPropertyAttribute  Name          if  String Equals childrenProperty   Content      String Equals childrenProperty   Children                          var collection   o GetType   GetProperty childrenProperty  GetValue o  null               if  collection is System Windows Controls UIElementCollection     snelson 6 6 11                               foreach  var c in  IEnumerable collection                                        if  c GetType   FullName    childType FullName                          list Add c                       if  maxDepth    0    depth  lt  maxDepth                          list AddRange RecursiveFindControls                              c  childType  depth   1  maxDepth                                                else if  collection    null  amp  amp  collection GetType   BaseType Name     Panel      snelson 6 6 11  added because was skipping control  e g   System Windows Controls Grid                                if  maxDepth    0    depth  lt  maxDepth                      list AddRange RecursiveFindControls                          collection  childType  depth   1  maxDepth                                      return list ToArray

User · Answer

Try this    lt TextBlock x Name  txtblock  FontSize  24   gt Hai Welcom to this page  lt  TextBlock gt    Code Behind  var txtblock   sender as Textblock  txtblock Foreground    Red

User · Answer

I may be just repeating everyone else but I do have a pretty piece of code that extends the DependencyObject class with a method FindChild   that will get you the child by type and name  Just include and use   public static class UIChildFinder       public static DependencyObject FindChild this DependencyObject reference  string childName  Type childType                DependencyObject foundChild   null          if  reference    null                        int childrenCount   VisualTreeHelper GetChildrenCount reference               for  int i   0  i  lt  childrenCount  i                                  var child   VisualTreeHelper GetChild reference  i                      If the child is not of the request child type child                 if  child GetType      childType                                           recursively drill down the tree                     foundChild   FindChild child  childName  childType                                     else if   string IsNullOrEmpty childName                                         var frameworkElement   child as FrameworkElement                         If the child s name is set for search                     if  frameworkElement    null  amp  amp  frameworkElement Name    childName                                                   if the child s name is of the request name                         foundChild   child                          break                                                          else                                          child element found                      foundChild   child                      break                                                    return foundChild            Hope you find it useful

[wpf] How can I find WPF controls by name or type?

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