public void SetClearValue() { using(var form = new Form()) { var button = new Button(); form.Controls.Add(button); var viewModel = new TestViewModel() { StringProperty = "test", StringProperty2 = "test2" }; form.SetDataContext(viewModel); BindingManager manager = new BindingManager(); manager.SetBinding(button, DataContextProvider.DataContextProperty, new Binding(() => viewModel.StringProperty)); manager.SetValue(button, DataContextProvider.DataContextProperty, "value"); Assert.That(button.GetDataContext(), Is.EqualTo("value")); Assert.That(manager.GetBindingActions().Count(), Is.EqualTo(0)); Assert.That(manager.GetValueActions().Count(), Is.EqualTo(1)); SetValueAction action = manager.GetValueActions().First(); Assert.That(action.Control, Is.EqualTo(button)); Assert.That(((AttachedPropertyDescriptor)action.Property).Property, Is.EqualTo(DataContextProvider.DataContextProperty)); Assert.That(action.Value, Is.EqualTo("value")); Assert.That(manager.FindAction(button, AttachedPropertyDescriptor.FromAttachedProperty(DataContextProvider.DataContextProperty)), Is.EqualTo(action)); manager.SetValue(button, DataContextProvider.DataContextProperty, "value2"); Assert.That(manager.GetBindingActions().Count(), Is.EqualTo(0)); Assert.That(manager.GetValueActions().Count(), Is.EqualTo(1)); Assert.That(button.GetDataContext(), Is.EqualTo("value2")); action = manager.GetValueActions().First(); Assert.That(action.Control, Is.EqualTo(button)); Assert.That(((AttachedPropertyDescriptor)action.Property).Property, Is.EqualTo(DataContextProvider.DataContextProperty)); Assert.That(action.Value, Is.EqualTo("value2")); manager.ClearValue(button, DataContextProvider.DataContextProperty); Assert.That(manager.GetBindingActions().Count(), Is.EqualTo(0)); Assert.That(manager.GetValueActions().Count(), Is.EqualTo(0)); Assert.That(button.GetDataContext(), Is.Null); } }