Creating and Working with InteropForms

Overview
This topic lists the tasks of involved in using the Interop Forms Toolkit to create .NET forms and make it accessible for use in a Visual Basic 6.0 application. The tasks below walk through project setup and how to expose different form members to Visual Basic 6.0. The tasks can be read sequentially, for those new to the Toolkit, or jumped to individually for quick reference.

Tasks

Configure a .NET InteropForm Project

Create a Form Property

Create a Form Method

Create an Initialize Method

Create a Form Event

Generate InteropForm Wrapper Classes

Configure the Visual Basic 6.0 Project

Instantiate an InteropForm

Call an InteropForm Initialize Method

Handle an InteropForm Event

Type Restrictions
One goal of this Interop Forms Toolkit is to keep development simple and straightforward, allowing developers to spend time developing features that add value instead of debugging Interop related issues. In keeping with that goal, only a subset of Types will be supported as parameters or return types for Interop members. They are:

• Integer (Int32)
• String
• Boolean
• Object

A warning dialog will appear during the code generation process notifying the developer if a member will be skipped because it uses an unsupported type.

Note: Object is supported to allow you to pass any custom object through and cast as needed. An example of this could be to pass a Recordset from Visual Basic 6.0 to .NET.

InteropForm Behavioral Nuances

Since Visual Basic 6.0 Forms and .NET Forms are very different there are a few nuances to keep in mind while developing.

Bringing a Visual Basic 6.0 Form to the front brings all Visual Basic 6.0 Forms to the front.
A .NET form showing Visual Basic 6.0 form modally doesn't work. A Visual Basic 6.0 Form is only modal to other Visual Basic 6.0 Forms.
A Visual Basic 6.0 Form showing another Visual Basic 6.0 Form modally works; however, the modal form only "flickers" to indicate modality when another Visual Basic 6.0 form, not a .NET form, is clicked.
InteropForms cannot be used as MDI Child forms in Visual Basic 6.0. If you want to extend an MDI Form, use an Interop User Control on a Visual Basic 6.0 MDI Child form and size it to fit the entire client area of the form.

For more information on the working with the .NET InteropForm see The Development Experience.