Allow only OneWayToSource binding mode

Question

I have EntitiesUserControl responsible for EntitiesCount dependency property:

public static readonly DependencyProperty EntitiesC         


        

Answer 1

It's a „bit” hacky, but you can create a Binding-derived class and use that instead of Binding:

[MarkupExtensionReturnType(typeof(OneWayToSourceBinding))]
public class OneWayToSourceBinding : Binding
{
    public OneWayToSourceBinding()
    {
        Mode = BindingMode.OneWayToSource;
    }

    public OneWayToSourceBinding(string path) : base(path)
    {
        Mode = BindingMode.OneWayToSource;
    }

    public new BindingMode Mode
    {
        get { return BindingMode.OneWayToSource; }
        set
        {
            if (value == BindingMode.OneWayToSource)
            {
                base.Mode = value;
            }
        }
    }
}

In XAML:

<controls:EntitiesUserControl EntitiesCount="{local:OneWayToSourceBinding CountOfEntities}" />

The namespace mapping local might be something else for you.

This OneWayToSourceBinding sets the Mode to OneWayToSource and prevents setting it to anything else.