User defined data.
[Visual Basic .NET] Public ReadOnly Property UserData As Object
[C#] public object UserData {get;}
Product Availability
Available with ArcGIS Desktop.
Description
Use the UserData property to return any custom data specific to your dockable window definition class.
Remarks
The custom user defined data can be retreived from the actual dockable window object created by the application via the IDockableWindow::UserData property.