Invalid PropertyDescriptor Value -- please help!

Invalid PropertyDescriptor Value -- please help!

• BruceTT

  By the way, I have run the sample posted by Simon but with bool instead of int and it is working fine. Don't forget to rebuild the entire solution before running it, there is a bug in Feb CTP.
  
  
  

• Aggag

  Thanks for the help Simon. :)
  

• Lorenz Buchberger

  As chaz pointed out in the other thread...

  public static readonly DependencyProperty TestProperty = DependencyProperty.RegisterAttached("Test", typeof(int), typeof(Window2), new UIPropertyMetadata(false));

  
  
  

• satishdayala

  I've done this with an int rather than a bool but...

  If you set your property up as an attached dependency property and then call SetValue to change it, the style of your contol will change. You need to decalre an xmlns specifier for the assembly that your class is in, and then reference the property by 'xmlns:class.property'.
  
  <Window x:Class="TestThingie.Window2"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="Renamer" Height="300" Width="300"
  xmlns:local="clr-namespace:TestThingie;assembly=TestThingie">
  
  <Window.Resources>
  <Style TargetType="{x:Type Button}">
  <Style.Triggers>
  <Trigger Property="local:Window2.Test" Value="0">
  <Setter Property="BitmapEffect">
  <Setter.Value>
  <OuterGlowBitmapEffect GlowColor="Red" GlowSize="4"/>
  </Setter.Value>
  </Setter>
  </Trigger>
  </Style.Triggers>
  </Style>
  </Window.Resources>
  
  <Grid Margin="20">
  <Button x:Name="MyButton" Content="Click me" Height="25" Click="OnClick"/>
  </Grid>
  </Window>
  
  public partial class Window2 : Window
  {
  [BindableAttribute(true)]
  public int Test
  {
  get { return (int)GetValue(TestProperty); }
  set { SetValue(TestProperty, value); }
  }
  
  public static readonly DependencyProperty TestProperty = DependencyProperty.RegisterAttached("Test", typeof(int), typeof(Window2), new UIPropertyMetadata(0));
  
  public static int GetTest(UIElement element)
  {
  return (int)element.GetValue(TestProperty);
  }
  
  public static void SetTest(UIElement element, int value)
  {
  if (element != null)
  {
  element.SetValue(TestProperty, value);
  }
  else
  {
  throw new ArgumentNullException();
  }
  }
  
  public Window2()
  {
  
  }
  
  void OnClick(object sender, RoutedEventArgs e)
  {
  SetTest(this.MyButton, 5);
  }
  }
  

  
  
  

• Rochak

  There really isn't much to post - just the DependancyProperty (used the Insert Snippet functionality) and I set the value of the property in the window object's constructor.

   

  public partial class Window2 : Window {
      public bool Test {
          get { return (bool)GetValue(TestProperty); }
          set { SetValue(TestProperty, value); }
      }

      // Using a DependencyProperty as the backing store for Test.  This enables animation, styling, binding, etc...
      public static readonly DependencyProperty TestProperty =
          DependencyProperty.Register("Test", typeof(bool), typeof(Window2), new UIPropertyMetadata(0));

      public Window2() {
          InitializeComponent();
         
          Test = true;
      }
  }

  
  

• ron2464

  It looks like a schema issue, ignore it. However, you'll need to wrap your trigger up in a style and give the style a target type. Here's an example with a button an IsMouseOver

  You might have issues with creating a dp in the code behind for your window, try doing it in a custom control.

  <Window x:Class="TriggersTest.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="TriggersTest" Height="300" Width="300">
  <Window.Resources>
  <Style TargetType="{x:Type Button}">
  <Style.Triggers>
  <Trigger Property="IsMouseOver" Value="True">
  <Setter Property="Background" Value="Blue"/>
  </Trigger>
  </Style.Triggers>
  </Style>
  </Window.Resources>
  
  <Grid Margin="20">
  <Button Content="Hover Over Me" Height="25"/>
  </Grid>
  </Window>

  
  
  

• CliftNorris

  That's why I did it as an int... :)

  If you breakpoint on the DependencyProperty initializer and do a quick watch on that line you'll notice it throws an ArugmentException saying that the specified type doesn't match that of the property.

  Stick with the int for now, I've posted another question about the bool...

  
  
  

• Ryo

  Can you post the relavent bit from the codebehind
  
  

• Laurensvp

  Okay, that works.

  Course when I try to change the property from int to bool, it blows up..........

  *sigh* What am I doing wrong

  By 'blows up' I mean that when I run the application, I get an exception at "App.Run()" in app.xaml.cs, with this text:

  System.Windows.Markup.BamlParseException was unhandled
  Message="Error at element '' in markup file 'Window2.xaml' : Exception has been thrown by the target of an invocation.."
  Source="PresentationFramework"
  

  Doesn't mean squat to me... There's a huge stack trace after this but nothing pointing at my code.

  
  

• Seb69

  Okay, that works, but it isn't what I want.

  What I want is to be able to use a property of the Window1 class to modify the style of a single specific control via triggers.

  
  

• a_takavci

  I have been rebuilding the entire solution - in fact, I created a whole new one, pasted in the code, and ran it with the same result - exception.

  
  
• Invalid PropertyDescriptor Value -- please help!