How can I find WPF controls by name or type?

WpfControlsFind

Wpf Problem Overview


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

Wpf Solutions


Solution 1 - Wpf

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.

/// <summary>
/// Finds a Child of a given item in the visual tree. 
/// </summary>
/// <param name="parent">A direct parent of the queried item.</param>
/// <typeparam name="T">The type of the queried item.</typeparam>
/// <param name="childName">x:Name or Name of child. </param>
/// <returns>The first parent item that matches the submitted type parameter. 
/// If not matching item can be found, 
/// a null parent is being returned.</returns>
public static T FindChild<T>(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 < 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<T>(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 && 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<TextBox>(Application.Current.MainWindow, "myTextBoxName");

Note Application.Current.MainWindow can be any parent window.

Solution 2 - Wpf

You can also find an element by name using FrameworkElement.FindName(string).

Given:

<UserControl ...>
    <TextBlock x:Name="myTextBlock" />
</UserControl>

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).

Solution 3 - Wpf

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
{
   /// <summary>
   /// Finds a parent of a given item on the visual tree.
   /// </summary>
   /// <typeparam name="T">The type of the queried item.</typeparam>
   /// <param name="child">A direct or indirect child of the queried item.</param>
   /// <returns>The first parent item that matches the submitted type parameter. 
   /// If not matching item can be found, a null reference is being returned.</returns>
   public static T FindVisualParent<T>(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<T>(parentObject);
      }
   }
}

Call it like this:

Window owner = UIHelper.FindVisualParent<Window>(myControl);

Solution 4 - Wpf

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 < 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);
                    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 && 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.

Solution 5 - Wpf

If you want to find ALL controls of a specific type, you might be interested in this snippet too

	public static IEnumerable<T> FindVisualChildren<T>(DependencyObject parent) 
		where T : DependencyObject
	{
		int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
		for (int i = 0; i < 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<T>(child))
			{
				yield return other;
			}
		}
	}

Solution 6 - Wpf

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

Solution 7 - Wpf

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

 /// <summary>
 /// Helper methods for UI-related tasks.
 /// </summary>
 public static class UIHelper
 {
   /// <summary>
   /// Finds a parent of a given item on the visual tree.
   /// </summary>
   /// <typeparam name="T">The type of the queried item.</typeparam>
   /// <param name="child">A direct or indirect child of the
   /// queried item.</param>
   /// <returns>The first parent item that matches the submitted
   /// type parameter. If not matching item can be found, a null
   /// reference is being returned.</returns>
   public static T TryFindParent<T>(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<T>(parentObject);
     }
   }

   /// <summary>
   /// This method is an alternative to WPF's
   /// <see cref="VisualTreeHelper.GetParent"/> method, which also
   /// supports content elements. Do note, that for content element,
   /// this method falls back to the logical tree of the element!
   /// </summary>
   /// <param name="child">The item to be processed.</param>
   /// <returns>The submitted item's parent, if available. Otherwise
   /// null.</returns>
   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);
   }
}

Solution 8 - Wpf

I edited CrimsonX's code as it was not working with superclass types:

public static T FindChild<T>(DependencyObject depObj, string childName)
   where T : DependencyObject
{
	// Confirm obj is valid. 
	if (depObj == null) return null;
	
	// success case
	if (depObj is T && ((FrameworkElement)depObj).Name == childName)
		return depObj as T;

	for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
	{
		DependencyObject child = VisualTreeHelper.GetChild(depObj, i);

		//DFS
		T obj = FindChild<T>(child, childName);

		if (obj != null)
			return obj;
	}

	return null;
}

Solution 9 - Wpf

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<T>(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<Window>();

Solution 10 - Wpf

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<object> list = new List<object>();
        var attrs = o.GetType()
            .GetCustomAttributes(typeof(ContentPropertyAttribute), true);
        if (attrs != null && attrs.Length > 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 < maxDepth)
                    list.AddRange(RecursiveFindControls(
                        c, childType, depth + 1, maxDepth));
            }
        }
        return list.ToArray();
    }
}

Solution 11 - Wpf

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<object> list = new List<object>();
    var attrs = o.GetType().GetCustomAttributes(typeof(ContentPropertyAttribute), true);
    if (attrs != null && attrs.Length > 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 < maxDepth)
                        list.AddRange(RecursiveFindControls(
                            c, childType, depth + 1, maxDepth));
                }
            }
            else if (collection != null && collection.GetType().BaseType.Name == "Panel") // snelson 6/6/11; added because was skipping control (e.g., System.Windows.Controls.Grid)
            {
                if (maxDepth == 0 || depth < maxDepth)
                    list.AddRange(RecursiveFindControls(
                        collection, childType, depth + 1, maxDepth));
            }
        }
    }
    return list.ToArray();
}

Solution 12 - Wpf

I have a sequence function like this (which is completely general):

    public static IEnumerable<T> SelectAllRecursively<T>(this IEnumerable<T> items, Func<T, IEnumerable<T>> func)
    {
        return (items ?? Enumerable.Empty<T>()).SelectMany(o => new[] { o }.Concat(SelectAllRecursively(func(o), func)));
    }

Getting immediate children:

    public static IEnumerable<DependencyObject> FindChildren(this DependencyObject obj)
    {
        return Enumerable.Range(0, VisualTreeHelper.GetChildrenCount(obj))
            .Select(i => VisualTreeHelper.GetChild(obj, i));
    }

Finding all children down the hiararchical tree:

    public static IEnumerable<DependencyObject> FindAllChildren(this DependencyObject obj)
    {
        return obj.FindChildren().SelectAllRecursively(o => 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).

Solution 13 - Wpf

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.

Solution 14 - Wpf

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 <TypeToFind>}}}" 

Solution 15 - Wpf

Here is a solution that uses a flexible predicate:

public static DependencyObject FindChild(DependencyObject parent, Func<DependencyObject, bool> predicate)
{
    if (parent == null) return null;

    int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
    for (int i = 0; i < 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 =>
{
    var textBlock = child as TextBlock;
    if (textBlock != null && textBlock.Name == "MyTextBlock")
        return true;
    else
        return false;
}) as TextBlock;

Solution 16 - Wpf

I can't find my control with @CrimsonX or @Drew Noakes methods, because my ControlTemplate is located in a separated XAML file. I have found the control using the following method:

private Image backImage;
private void Diagram_Loaded(object sender, System.Windows.RoutedEventArgs e)
{
    // here is the example of the ControlTemplate declaration
    //<ControlTemplate x:Key="DiagramControlTemplate1" TargetType="{x:Type Diagram}">
    var ctrlTemplate = (ControlTemplate)FindResource("DiagramControlTemplate1");
    // diagram is the x:Name of TemplatedControl and, "backImage" is the name of control that I want to find.
    var imageControl = ctrlTemplate.FindName("backImage", diagram);
    if (imageControl != null)
    {
        this.backImage = (Image)imageControl;
    }
}

This is working for me.

Solution 17 - Wpf

To find an ancestor of a given type from code, you can use:

[CanBeNull]
public static T FindAncestor<T>(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<T>(DependencyObject d) where T : DependencyObject
{
    while (true)
    {
        d = VisualTreeHelper.GetParent(d);

        if (d == null)
            return null;

        if (d is T t)
            return t;
    }
}

Solution 18 - Wpf

This code just fixes @CrimsonX answer's bug:

 public static T FindChild<T>(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 < 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<T>(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 && frameworkElement.Name == childName)
          {
            // if the child's name is of the request name
            foundChild = (T)child;
            break;
          }

 // recursively drill down the tree
          foundChild = FindChild<T>(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.

Solution 19 - Wpf

I was able to find objects by name using below code.

stkMultiChildControl = stkMulti.FindChild<StackPanel>("stkMultiControl_" + couter.ToString());

Solution 20 - Wpf

Try this

<TextBlock x:Name="txtblock" FontSize="24" >Hai Welcom to this page
</TextBlock>

Code Behind

var txtblock = sender as Textblock;
txtblock.Foreground = "Red"

Attributions

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
Questionalex2k8View Question on Stackoverflow
Solution 1 - WpfCrimsonXView Answer on Stackoverflow
Solution 2 - WpfDrew NoakesView Answer on Stackoverflow
Solution 3 - WpfJohn MyczekView Answer on Stackoverflow
Solution 4 - WpfTri Q TranView Answer on Stackoverflow
Solution 5 - Wpfuser604613View Answer on Stackoverflow
Solution 6 - WpfGishuView Answer on Stackoverflow
Solution 7 - WpfPhilippView Answer on Stackoverflow
Solution 8 - WpfandrespView Answer on Stackoverflow
Solution 9 - WpfNathan PhillipsView Answer on Stackoverflow
Solution 10 - Wpfexciton80View Answer on Stackoverflow
Solution 11 - WpfShawn NelsonView Answer on Stackoverflow
Solution 12 - WpfVB GuyView Answer on Stackoverflow
Solution 13 - WpfEl ZorkoView Answer on Stackoverflow
Solution 14 - WpfNeerajView Answer on Stackoverflow
Solution 15 - WpfTim PohlmannView Answer on Stackoverflow
Solution 16 - WpfantonioView Answer on Stackoverflow
Solution 17 - WpfDrew NoakesView Answer on Stackoverflow
Solution 18 - WpfAmir OveisiView Answer on Stackoverflow
Solution 19 - WpfHardik ShahView Answer on Stackoverflow
Solution 20 - WpfJayasriView Answer on Stackoverflow