Question

Hey, I tried implementing a class John madeWatermark.

I’m stuck and wondered if anyone can help me …. Added the 2 classes mentioned
and on the wpf:

<AdornerDecorator>
        <ComboBox Height="23" HorizontalAlignment="Right" Margin="0,184,664,0" x:Name="cbVideoDevices" VerticalAlignment="Top" Width="316" Initialized="cbVideoDevices_Initialized" SelectionChanged="cbVideoDevices_SelectionChanged">
            <Controls:WatermarkService.Watermark>
                <TextBlock>Type here to search text</TextBlock>
            </Controls:WatermarkService.Watermark>
        </ComboBox>
    </AdornerDecorator>

Whatever I try, I keep getting errors as the Control doesn’t exist, or the Property does not exit. I get no errors in his classes so I figured the references are good but it seemed to me the System.Windows.Control is missing…. but I can’t find it to add it …

Any help, much appreciated.

Edit: With Liz’s help I got this to work but to let anyone know, who does use this.

• The AdornerDecorator Creates a box over everything …..
• Create the Margin for the AdornerDecorator and move that to desired position
• Margin and alignments screw with where the watermark is shown ….

Answer 1

I tried the example and it works for me.

However, I did notice the following:

The classes did not specify a namespace, so I added one for both classes. In my case “Watermark”.

namespace Watermark
{
  public static class WatermarkService
  {
   ...
  }
}

The WatermarkAdorner class in “internal”, but that shouldn’t bother you unless it is in a different assembly (dll). If it is then make it “public”

Then in the xaml, I added a namespace declaration

xmlns:Controls="clr-namespace:Watermark"

At that point everything worked fine.

My slightly simplified xaml looks like this:

<AdornerDecorator >
      <ComboBox Height="23"  x:Name="cbVideoDevices"   
                             Initialized="cbVideoDevices_Initialized"                       
                             SelectionChanged="cbVideoDevices_SelectionChanged">
        <controls:WatermarkService.Watermark>
          <TextBlock>Type here to search text</TextBlock>
        </controls:WatermarkService.Watermark>
      </ComboBox>
    </AdornerDecorator>

Other than removing your margins, and alignment, it is basically the same as yours.

Does that help?

As a side-note I didn’t like the fact that the watermark still showed when an item was selected in the combobox, so I changed the Control_Loaded method in the WatermarkService as follows:

private static void Control_Loaded(object sender,RoutedEventArgs e)
{
  Control control = (Control)sender;
  if(ShouldShowWatermark(control))
  {
    ShowWatermark(control);
  }
  else
  {
    RemoveWatermark(control);
  }
}