Question

I have a custom control with an event handler when you click on it. Everything works and the event get fired right.

    AddHandler (cu.MouseLeftButtonDown), AddressOf Me.DoSomething

When the control resizes to show some extra information it expands. It also collapses when the user preses a button. This works alright. But now when I click where the expanded area used to be, it still fires mouse leftbuttondown on that control. I have tried to set IsHitTestVisible to false on the expanded element but it diden’t work. Here’s some xaml…

 <UserControl x:Class="MyCustomControl">
     <StackPanel>
       <Grid>
          'Stuff thats always visible
       </Grid>
    <Border IsHitTestVisible="False"   Grid.Row="1" HorizontalAlignment="left" BorderThickness="1" VerticalAlignment="top" x:Name="overView" Background="#EEEEEE" Visibility="Hidden" Margin="-325,-95,0,0" Width="auto" Height="auto" Padding="5,5,5,5" BorderBrush="#999999" CornerRadius="3,3,3,3">
        <Border IsHitTestVisible="False" x:Name="myBorder" Margin="1" Width="300" Height="225" BorderThickness="1" BorderBrush="#999999" Background="#DDDDDD" CornerRadius="3,3,3,3" HorizontalAlignment="Left" VerticalAlignment="Top">
            <Rectangle IsHitTestVisible="False" x:Name="rtgOverView">
            </Rectangle>
        </Border>
    </Border>
   </StackPanel>
 </UserControl>

The overview becomes visible when I use this code

  overView.Visibility = Windows.Visibility.Visible

And hides when I use this

  OverView.Visibility = Windows.Visibility.Collapsed

I fill the rectangle with a visualbrush. This happens when the control is loaded.

   rtgOverView.Fill = visual 

The overView gets positioned in code behind like this

    If x > 350 Then
        overView.HorizontalAlignment = Windows.HorizontalAlignment.Left
        overView.Margin = New Thickness(-325, -95, 0, 0)
    Else
        overView.HorizontalAlignment = Windows.HorizontalAlignment.Right
        overView.Margin = New Thickness(0, -95, -300, 0)
    End If

I cant use another element around my customcontrol since I also use this MouseLeftButtonDown on all different kind of controls.
I can’t figure out how the boundaries on the cu.MouseLeftButtonDown event work to fix this.

Answer 1

There was something weird going on with the size of the stackpanel. It’s like the auto property doesn’t size it smaller. I managed to fix it like this. When the mouse enters I put:

 layoutroot.ClipToBounds = False 

This allows me to show content outside the control.
When the mouse leaves I use:

 layoutroot.ClipToBounds = True

The clip to bound’s somehow forces the StackPanel to size smaller.