Making an activity’s display name readonly in the Workflow 4 designer

[This article was contributed by the AppFabric team.]

To make an activity’s display name readonly, it isn’t enough to use the ReadOnlyAttribute on the DisplayName. In order to do this, create a custom PropertyValueEditor that displays a string in a text block, then declare an editor attribute on the “DisplayName” property of your activity. The following code demonstrates how to create a read-only custom PropertyValueEditor.

public class ReadOnlyStringEditor : PropertyValueEditor
  {
      public ReadOnlyStringEditor()
      {
          FrameworkElementFactory factory = new FrameworkElementFactory(typeof(TextBlock));
          factory.SetBinding(TextBlock.TextProperty, new Binding("Value"));
          this.InlineEditorTemplate = new DataTemplate();
          this.InlineEditorTemplate.VisualTree = factory;
      }
  }

The following code demonstrates how to assign the custom property editor. This should be done in the constructor for the designer.

// Add attribute onto MyCustomActivity.DisplayName
  AttributeTableBuilder builder = new AttributeTableBuilder();
  builder.AddCustomAttributes(typeof(Activity), "DisplayName", new EditorAttribute(typeof(ReadOnlyStringEditor), typeof(PropertyValueEditor)));
  MetadataStore.AddAttributeTable(builder.CreateTable());

Finally, assign the display name in the custom activity’s constructor.



this.DisplayName = "Custom Sequence Activity";