How to Fix 'cannot convert from 'System.Windows.PropertyChangedCallback' to 'System.Windows.PropertyMetadata' ?

08-20-2008 11:24 AM |

I am trying to build Delay's sample from "Lying to the layout system for a good cause [Bringing LayoutTransform to Silverlight 2!]" and I get 7 errors when building with VSTS 2008 SP1. Six of the errors are from code like the following:

private static void ChildChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
...
}

 public static readonly DependencyProperty ContentProperty = DependencyProperty.Register(
    "Child", typeof(FrameworkElement), typeof(LayoutTransformControl), new PropertyMetadata(ChildChanged));

The problem stems from the type conversion of the ChildChanged parameter to  PropertyMetadata.
This follows then MSDN documentation.

Does anyone know how to fix this?

THANKS MUCH.

Re: How to Fix 'cannot convert from 'System.Windows.PropertyChangedCallback' to 'System.Windows.PropertyMetadata' ?

08-20-2008 11:38 AM |

For a bit of background, this was changed from Beta 1 to Beta 2, the new format is consistent with WPF. The suggestion above is correct.

Re: How to Fix 'cannot convert from 'System.Windows.PropertyChangedCallback' to 'System.Windows.PropertyMetadata' ?

08-20-2008 11:44 AM |

Skyrunner:

Replace by

new PropertyMetadata(new PropertyChangedCallback(ChildChanged))

That didn't work.

I changed it to:

        public static readonly DependencyProperty ContentProperty = DependencyProperty.Register(
            "Child", typeof(FrameworkElement), typeof(LayoutTransformControl), new PropertyMetadata(new PropertyChangedCallback(ChildChanged)));

and still getting the same error:

Error 2 Argument '4': cannot convert from 'System.Windows.PropertyChangedCallback' to 'System.Windows.PropertyMetadata' 

Re: How to Fix 'cannot convert from 'System.Windows.PropertyChangedCallback' to 'System.Windows.PropertyMetadata' ?

08-20-2008 12:01 PM |

I'm sorry.

I didn't notice that Delay had the following code defined:

#if SILVERLIGHT
using PropertyMetadata = System.Windows.PropertyChangedCallback;
#endif

 Once I commented that out, the fix worked fine.

 THANKS MUCH !!