public override object ProvideValue(IServiceProvider serviceProvider)
{
_bindableParam = new BindableParameter();
//set the binding of the parameter
BindingOperations.SetBinding(_bindableParam, BindableParameter.ParameterProperty, Binding);
_bindableParam.TargetProperty = TargetProperty;
return(_bindableParam);
}
/// <summary>
/// Handles changes to the BindParameter property.
/// </summary>
private static void OnBindParameterChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
FrameworkElement element = d as FrameworkElement;
if (element == null)
{
throw new InvalidOperationException("BindableParameter can be applied to a FrameworkElement only");
}
BindableParameter parameter = (BindableParameter)e.NewValue;
element.Initialized += delegate
{
parameter.TargetExpression = BindingOperations.GetBindingExpression(element, parameter.TargetProperty);
parameter.TargetBinding = BindingOperations.GetBinding(element, parameter.TargetProperty);
//update the converter parameter
InvalidateBinding(parameter);
};
}
private static void InvalidateBinding(BindableParameter param)
{
if (param.TargetBinding != null && param.TargetExpression != null)
{
//this is a hack to trick the WPF platform in thining that the binding is not sealed yet and then change the value of the converter parameter
bool isSealed = (bool)isSealedFieldInfo.GetValue(param.TargetBinding);
if (isSealed) //change the is sealed value
{
isSealedFieldInfo.SetValue(param.TargetBinding, false);
}
param.TargetBinding.ConverterParameter = param.ConverterParameterValue;
if (isSealed) //put the is sealed value back as it was...
{
isSealedFieldInfo.SetValue(param.TargetBinding, true);
}
//force an update to the binding
param.TargetExpression.UpdateTarget();
}
}
/// <summary>
/// Sets the BindParameter property. This dependency property
/// indicates ....
/// </summary>
public static void SetBindParameter(DependencyObject d, BindableParameter value)
{
d.SetValue(BindParameterProperty, value);
}
