Using ITypeDiscoveryService within the SmartTag

Each web control offers a SmartTag. It’s that little arrow on the right edge of the control and pops up a list of commands. Here’s how to add a command where the user can pick from a list of types. This is an extension of the Using ITypeDiscoveryService in a TypeConverter post.

The idea is very easy.

1. Create a TypeConverter that implements GetStandardValues().

2. Create a command in the SmartMenu for the Type property. It should be of type “string”.

3. Assign the TypeConverter to that property.

The SmartTag will build a dropdownlist using your TypeConverter.

Here’s how I implemented the POCOTypeName property found in the POCODataSource control of Versatile DataSources.

TypeConverter

The new type converter is based on BaseTypeNameTypeConverter from the earlier post.

public class POCOTypeNameTypeConverter : BaseTypeNameTypeConverter
{
   public override bool SupportedType(Type pTypeToEvaluate)
   {
      if (typeof(DataContext.IAutoRegisterWithPOCODataContext).IsAssignableFrom(pTypeToEvaluate))
         return true;
      if (typeof(System.Web.UI.Control).IsAssignableFrom(pTypeToEvaluate))
         return false;

// eliminate DataContext, Entity, and EntityDAO classes
      if (Attribute.GetCustomAttributes(pTypeToEvaluate, typeof(EntityDAOTypeAttribute), true).Length > 0)
         return false;

      if (Attribute.GetCustomAttributes(pTypeToEvaluate, typeof(EntityDAODataSourceDefaultsAttribute), true).Length > 0)
         return false;

      if (typeof(DataContext.IEntityFactoryDataContext).IsAssignableFrom(pTypeToEvaluate))
         return false;

      if (pTypeToEvaluate.Name == "global_asax")
         return false;

      return true;
   }
}

ActionList class for SmartTag

public class POCODataSourceDesignerActionList : DesignerActionList
{
   protected System.Web.UI.Control fControl = null;

   public POCODataSourceDesignerActionList(POCODataSource pComponent)
      : base(pComponent)
   {
      fControl = (System.Web.UI.Control)pComponent;
   }

   public override DesignerActionItemCollection GetSortedActionItems()
   {
      DesignerActionItemCollection vItems = new DesignerActionItemCollection();

      vItems.Add(new DesignerActionPropertyItem("POCOTypeName",
                          "Full name of the POCO class", "",
                          "Provides the name of a type that represents the POCO class."));
      return vItems;
   }

   [TypeConverter(typeof(Designer.POCOTypeNameTypeConverter))]
   public virtual string POCOTypeName
   {
      get
      {
         return ((POCODataSource)fControl).POCOTypeName;
      }
      set
      {
         TypeDescriptor.GetProperties(fControl)["POCOTypeName"].SetValue(fControl, value);
      }
   }
}

ControlDesigner class

public class POCODataSourceDesigner : System.Web.UI.Design.ControlDesigner
{
   public override DesignerActionListCollection ActionLists
   {
      get
      {
         if (null == fActionLists)
         {
            fActionLists = new DesignerActionListCollection();
            fActionLists.AddRange(base.ActionLists);

            fActionLists.Add(new POCODataSourceDesignerActionList((POCODataSource)this.Component));
         }
         return fActionLists;
      }
   }
   private DesignerActionListCollection fActionLists;
}

For more on SmartTags, see Designer Commands and the DesignerAction Object Model for Windows Forms

No Comments