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UIElementCollection.IndexOf Method

Returns the index position of a specified element in a UIElementCollection.

Namespace:  System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)

public virtual int IndexOf(
	UIElement element
)

Parameters

element
Type: System.Windows.UIElement
The element whose index position is required.

Return Value

Type: System.Int32
The index position of the element. -1 if the element is not in the collection.

The following example finds the index position of a UIElement within a UIElementCollection.


<DockPanel Name="ParentElement">

    <TextBlock DockPanel.Dock="Top" Name="TxtDisplay"></TextBlock>

    <Button DockPanel.Dock="Top" Click="FindIndex">What is the Index Number
        of the Element Just Added?</Button>
    <DockPanel Name="MainDisplayPanel">
        <TextBlock DockPanel.Dock="Top">Text 1</TextBlock>
        <TextBlock DockPanel.Dock="Top">Text 2</TextBlock>
    </DockPanel>
</DockPanel>


...


		private int c_counter = 0;
		void FindIndex(object sender, RoutedEventArgs e)
		{
			c_counter+=1;
			// Create a new Text element.
			TextBlock newText = new TextBlock();
			// Add this element to the UIElementCollection of the DockPanel element.
			MainDisplayPanel.Children.Add(newText);
			// Add a text node under the Text element. This text is displayed. 
			newText.Text = "New element #" + c_counter;
			DockPanel.SetDock(newText,Dock.Top);
			// Display the Index number of the new element.    
			TxtDisplay.Text = "The Index of the new element is " +  MainDisplayPanel.Children.IndexOf(newText);
		}


.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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