You may not want to add all of your logic straight on a single dialog depending on what you are trying to accomplish, but you just need to simply create a property in this case:Private _MyProperty As String
Public Property MyProperty As String
Get
Return _MyProperty
End Get
Set(Byval value As String)
_MyProperty = value
End Set
End Property
After it has been added, you will need to rebuild the project before it can be seen within a designer. Also, if you add this on a specific form, you will not see it within the designer unless the form () or user control, class, etc) is inherited.