SAMPLE: VB6WLCTL.EXE Windowless Controls Demonstration

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This article was previously published under Q189596

SUMMARY

Visual Basic 6.0 introduces the capability of creating "Windowless" controls. A Windowless control, also known as a "lightweight" control, is a control that does not have a WndProc function for message handling. These lightweight controls require fewer resources than normal controls, and allow for development of transparent controls. This sample demonstrates how to create windowless controls in Visual Basic 6.0.

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MORE INFORMATION

The following file is available for download from the Microsoft Download Center:

VB6WLCTL.exe (http://download.microsoft.com/download/vb60pro/2/2/win98/en-us/vb6wlctl.exe)

Release Date: June 16, 2000

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 (http://support.microsoft.com/kb/119591/EN-US/ ) How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file. Below is the content of the Readme.txt for this sample.

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Description

Visual Basic 6.0 provides the capability of building Windowless controls, also known as lightweight controls. A new property of the UserControl, Windowless, enables this feature. Setting the Windowless property to True will make the UserControl Windowless, a control which sends and receives messages through OLE rather than the regular messaging queues that Windows uses.

A Windowless control behaves the same as the normal UserControls with the following exceptions:

The UserControl has no hWnd property (limits some API calls).
The Borderstyle property cannot be set.
The UserControl cannot host normal Windowed controls.
Windowless controls are not supported by some containers. If sited in such a container, they will be assigned an hWnd and be treated as a normal Windowed controls.

This sample demonstrates the functionalities of Windowless controls created in Visual Basic 6.0. The main project group file is WndLessControlAGroup.vbg, which contains the controls as well as a client that shows the controls in action. The documentation in the source code explains in great detail the behavior of each control.

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Summary Of Sample Controls

Four Windowless Controls are included in the sample to show different Functionality:

TestControl1 - A Windowless control that acts and handles events like a
               normal control.

TestControl2 - Allows events to bypass it and be handled by the controls
               underneath it.

TestControl3 - Demonstrates "HitTesting" to see where the user has clicked
               within the Windowless control's region on the form. The
               control acts "transparently" (events being passed to the
               Form underneath) unless the CommandButton sited on it is
               clicked. Then it handles that Event normally.

TestControl4 - This control demonstrates how to determine what areas of a
               control are transparent by using the Picture, MaskPicture,
               and MaskColor properties, and where events can be handled.

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To Start

Before loading this sample into Visual Basic 6.0, the following steps need to be taken:

Copy the following files on the Visual Basic 6.0 or Visual Studio 6.0 installation CD-ROM in the ...\Common\Tools\VB\WINLESS folder to the Windows\System (Windows 95, Windows 98, or Windows Me) or Windows\System32 (Windows NT) folder:
```
      mswless.reg
      mswless.ocx

					
```
Double-click on mswless.reg to import information to the registry.
Register mswless.ocx by typing in the following command in the Windows Run dialog:
```
      RegSvr32 C:\Windows\System\mswless.ocx

					
```

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REFERENCES

For more information about lightweight controls in Visual Basic, please see the following articles in the Microsoft Knowledge Base:

184687 (http://support.microsoft.com/kb/184687/EN-US/ ) : INFO: Lightweight Controls in Visual Basic 6.0

184645 (http://support.microsoft.com/kb/184645/EN-US/ ) : HOWTO: Create Lightweight Controls with Visual Basic 6.0

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