CODEWITHSUNDEEP
c#wpfsilverlightwindows-phone-7windows-phone
Andrzej
Andrzej

Reputation: 858

One binding to user control works, second doesn't

I've created user control, the code for property which I want to bind is:

public Color Value
{
    get
    {
        return (Color)this.GetValue(this.ValueProperty);
    }
    set
    {
        this.SetValue(this.ValueProperty, value);
    }
}

public readonly DependencyProperty ValueProperty = 
    DependencyProperty.Register("Value", typeof(Color), 
    typeof(ColorSlider), new PropertyMetadata(Colors.Red))

I have two instances of this control in my page:

<local:ColorSlider x:Name="ColorsSlider1" />
<!--...-->
<local:ColorSlider x:Name="ColorsSlider3" />

And controls with values, that I want to bind to (from ColorSlider to Canvas and TextBlock):

<Canvas x:Name="TileCanvas" Grid.Column="0" Margin="30" Width="173" Height="173"
        Background="{Binding Value, ElementName=ColorsSlider1, Converter={StaticResource ColorToSolidBrushConverter}}">
    <TextBlock x:Name="TileText" Text="dsdfsdfsf"
               Foreground="{Binding Value, ElementName=ColorsSlider3, Converter={StaticResource ColorToSolidBrushConverter}}"/>
</Canvas>

So here's the problem. Binding to the Canvas works, but binding to the TextBlock doesn't! It is interesting that if I remove ColorSlider3 a binding to the TextBlock will work! Also the binding will update the TextBlock background if I set the binding to ColorSlider3.

So it seems that I can bind values only from the latest instance of one UserControl. Why is this the case and how can I fix it?

Upvotes: 0

Views: 179

Answers (2)

NestorArturo
NestorArturo

Reputation: 2516

Your Dependency Property is not correctly defined... lacks the static part, and don't need the "this":

public Color Value
{
  get
  {
    return (Color)this.GetValue(ValueProperty);
  }

  set
  {
    this.SetValue(ValueProperty, value);
  }
}

public static readonly DependencyProperty ValueProperty =
  DependencyProperty.Register("Value", typeof(Color),
  typeof(ColorSlider), new PropertyMetadata(Colors.Red));

EDIT -----------------

Good to know it works for you. However, the real reason MS decided it to be static... never though about it, but according to MSDN:

"Custom Dependency Properties.

If you want properties on your custom types to support value expressions, property invalidation, per-type default values, inheritance, data binding, animation, or styling, you should back these CLR properties with a dependency property following these guidelines and procedures:

  1. Register a dependency property using the Register method; this method returns a DependencyProperty, which you should store as an accessible static read-only field in your class..."

Upvotes: 2

MBen
MBen

Reputation: 3996

It seems you have it set to ColorsSlider2 instead of ColorsSlider3

Upvotes: 0

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