I found the following instruction for adding a webdatechooser to a webgrid column for use as an editor.

Step-By-Step Example

To start out place a WebGrid and WebDateChooser onto the form.
2b) In NetAdvantage 2004 Volume 3 and later:
While still in the Quick Designer, set the DataType property of the column to "System.DateTime".

3) Select the EditorControlId property of the column. In the list, select the WebDateChooser control.
4) Set the AllowUpdate Property to "Yes".
5) Set the Type Property to "Custom".
6) Set the DisplayLayout.AddNewBox.Hidden property to "false" so we can add rows to the Grid.

But after following the instruction, when i compile my code i get a type caste exception.

Please Help!