How to get ElementHost control, given one of WPF control's content - wpf

Question

I am trying to get a reference to ElementHost control. For example in the below code I need to initially use the “testImage” content of the WPF user control to lunch the event. The WPF control is added at run-time, so does the ElementHost control, so I can’t use the WPF control’s name or ElementHost’s name.
My logic is to get the parent WPF user control of the “testImage”, and then get the parent ElementHost of the WPF’s user control.
But I am having troubles writing it in code. Please advise. Thanks.
<UserControl x:Class="WpfTest”
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="300" Height="300">
<Grid>
<Label FontSize="10" Height="24" Margin="74,16,0,0" Name="testLabel" VerticalAlignment="Top" />
<Image Name="testImage" Stretch="Uniform" HorizontalAlignment="Left" Width="64" Height="81" VerticalAlignment="Top" Margin="8,0,0,0"/>
</Grid>
</UserControl>

Answer 1

Here is some code that might help you. The key points are:
Name the ElementHost when you create it at runtime
Make use the the help function FindVisualChildByName() to search the WPF tree to get the desired control
I Hope this helps!
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim ElementHost1 As New System.Windows.Forms.Integration.ElementHost
Dim WpfTest1 As New WindowsApplication1.WPFTest
ElementHost1.Dock = DockStyle.Fill
ElementHost1.Name = "ElementHost1"
ElementHost1.Child = WpfTest1
Me.Controls.Add(ElementHost1)
End Sub
Private Sub GetImageReference_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim ElementHost1 As System.Windows.Forms.Integration.ElementHost = Me.Controls("ElementHost1")
Dim TheGrid As System.Windows.Controls.Grid = CType(ElementHost1.Child, WPFTest).MyGrid
Dim ImageTest As System.Windows.Controls.Image = FindVisualChildByName(TheGrid, "testImage")
Stop
End Sub
Public Function FindVisualChildByName(ByVal parent As System.Windows.DependencyObject, ByVal Name As String) As System.Windows.DependencyObject
For i As Integer = 0 To System.Windows.Media.VisualTreeHelper.GetChildrenCount(parent) - 1
Dim child = System.Windows.Media.VisualTreeHelper.GetChild(parent, i)
Dim controlName As String = child.GetValue(System.Windows.Controls.Control.NameProperty)
If controlName = Name Then
Return child
Else
Dim res = FindVisualChildByName(child, Name)
If Not res Is Nothing Then
Return res
End If
End If
Next
Return Nothing
End Function