Information
The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.

UIElementCollection.IndexOf Method

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

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

'Declaration
Public Overridable Function IndexOf ( _
	element As UIElement _
) As Integer

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>

...

	Dim c_counter as Integer = 0
    Private Sub FindIndex(ByVal sender As Object, ByVal args As RoutedEventArgs)
        Try 
            Dim newText As TextBlock = New TextBlock()
            c_counter = c_counter + 1
            ' 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 #" & CStr(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)
        Catch ex As System.Exception
            System.Windows.MessageBox.Show(ex.Message)
        End Try 
    End Sub

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

Show:
© 2014 Microsoft