This article contains information about the
supportability of using Microsoft .NET Windows Forms (Winforms) controls in an
unmanaged application. These unmanaged applications may include Microsoft Visual Basic 6.0 applications, Microsoft
Foundation Classes (MFC) applications, or Microsoft Internet Explorer.
Scenario 1: Host Winforms components as ActiveX controls
In the Microsoft .NET Framework 1.0, Winforms only supports
using Winforms controls in the following:
- Windows Forms
- Internet Explorer 5.01 and later versions
Winforms controls that are registered as ActiveX controls are
not supported. Winforms controls that are created by using the
CoCreateInstance
function are also not supported.
In the Microsoft .NET Framework 1.1,
support has been extended to include MFC 7.
x and later versions and any
container that is fully compatible with the MFC 7.
x ActiveX control
container. However, Winforms controls that are registered as ActiveX controls are
still not supported. Winforms controls that are created by using the
CoCreateInstance
function are also not supported. Winforms only supports the managed activation of
Winforms controls. When the Winforms controls are created, the controls can
be hosted in MFC like other ActiveX controls.
To use
Winforms controls in your application, you have to either host the
common language runtime by using the unmanaged CLR hosting APIs or use the
Managed Extensions for C++ to implement your application. We recommend that
you use Managed Extensions for C++.
Scenario 2: Display a Winforms form from an unmanaged
application
In the .NET Framework, you can display a Winforms form from an unmanaged application, such as a Visual
Basic 6.0
application or an
MFC 6.0
application. This scenario is supported. You can create a class library in
Winforms that includes a method to display the form, and then build the class
library for COM Interop. After you create and build the class library, you can use the Interop .dll file from
Visual Basic 6.0 or from MFC, and then call the method to display the form. The key is
to create a Winforms message pump in the Winforms form. The
Winforms form can then run on the message pump.
You can start a Winforms message pump using one of the following methods:
- Use the Form.ShowDialog() method to start a Winforms
message pump for the form.
- Put the form on a separate thread, and then call the Application.Run (newForm1) method to start the Winforms message pump on that thread. If you use this method to start the message pump, you must marshal any calls to the form from the unmanaged application. To do this, use the Control.Invoke method or an equivalent method.
For Win32 Interop, there are only two supported scenarios:
- Create a new thread, and then use the Form.ShowDialog() method or
the Application.Run() method. The Winforms message pump is
used to dispatch for the thread.
- Winforms code is hosted in MFC 7.x or Internet
Explorer as an ActiveX control. In this scenario, you have to wrap up the
managed code in an ActiveX control, and then use the ActiveX control as the
hosting interface.
Note Subclassing or setting a form's parent to be a Win32 parent is
not supported in any circumstance.