How can I evaluate a binding path dynamically, that is, the actual path comes from a property? For example, suppose I have a property of DisplayMemberPath, and I wanted to have something like:
Content="{Binding Path=(DisplayMemberPath)}" I know that this doesn't work, it's just to explain what I wanted. I know how to build a custom DataTemplate by code and set it dynamically, but that's not what I want.
You can use a custom behavior:
<SomeControl> <Interaction.Behaviors> <DynamicBindingBehavior TargetProperty="Content" BindingPath="{Binding DisplayMemberPath}"/> </Interaction.Behaviors> ... </SomeControl> and the code:
public class DynamicBindingBehavior : Behavior<DependencyObject> { private string m_targetProperty; public string TargetProperty { get { return m_targetProperty; } set { m_targetProperty = value; TryFindTargetProperty(); } } private DependencyProperty m_targetDependencyProperty; private void TryFindTargetProperty() { if (m_targetProperty == null || AssociatedObject == null) { m_targetDependencyProperty = null; } else { var targetDependencyPropertyInfo = AssociatedObject.GetType() .GetProperty( TargetProperty + "Property", typeof( DependencyProperty ) ); m_targetDependencyProperty = (DependencyProperty) targetDependencyPropertyInfo.GetValue( AssociatedObject, null ); } } public string BindingPath { get { return (string) GetValue( BindingPathProperty ); } set { SetValue( BindingPathProperty, value ); } } public static readonly DependencyProperty BindingPathProperty = DependencyProperty.Register( "BindingPath", typeof( string ), typeof( DynamicBindingBehavior ), new PropertyMetadata( BindingPathChanged ) ); private static void BindingPathChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { ((DynamicBindingBehavior) d).BindingPathChanged(); } private void BindingPathChanged() { if (m_targetDependencyProperty == null) return; if (BindingPath == null) { AssociatedObject.ClearValue(m_targetDependencyProperty); } else { BindingOperations.SetBinding( AssociatedObject, m_targetDependencyProperty, new Binding( BindingPath ) ); } } protected override void OnAttached() { base.OnAttached(); TryFindTargetProperty(); } protected override void OnDetaching() { if (m_targetDependencyProperty != null) AssociatedObject.ClearValue( m_targetDependencyProperty ); base.OnDetaching(); m_targetDependencyProperty = null; } } 