Microsoft KB Archive/138664

= DOC: GetClientRect May Assert in OLE Controls =

Article ID: 138664

Article Last Modified on 11/21/2006

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APPLIES TO

 Microsoft Foundation Class Library 4.2, when used with:  Microsoft OLE Control Developer's Kit (CDK)

 Microsoft Visual C++ 4.0 Professional Edition

 Microsoft Visual C++ 4.1 Subscription

 Microsoft Visual C++ 4.2 Professional Edition</li></ul>

 Microsoft Visual C++ 4.2 Enterprise Edition</li></ul>

 Microsoft Visual C++ 5.0 Learning Edition</li></ul>

 Microsoft Visual C++ 5.0 Learning Edition</li></ul> </li></ul>

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This article was previously published under Q138664

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SUMMARY
In chapter 4 of the Ole Control Tutorial, the section labeled Setting the CircleOffset Property Step 2, which describes how to implement the InBounds function, incorrectly calls GetClientRect and should read as follows instead:

<ol>  Add the function implementation at the end of your CIRCCTL.CPP file: BOOL CCirc2Ctrl::InBounds(short nOffset) {        int diameter; int length; int cx; int cy;

// Note that GetControlSize is called here instead of       // GetClientRect

GetControlSize(&cx, &cy);

if (cx > cy) {           length = cx; diameter = cy; }        else {           length = cy; diameter = cx; }        if (nOffset < 0) nOffset = (short) -nOffset; return (diameter / 2 + nOffset) <= (length / 2); }                       </li></ol>

This documentation error was corrected in Visual C++ version 5.0.

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MORE INFORMATION
In some control containers (such as Visual Basic and Microsoft Access) in design mode, the control has no window, and therefore no hwnd, so calling GetClientRect(rc) will assert.

There are actually two solutions to this problem. The first solution is documented in the "Summary" section of this article. The second solution is to replace the call to GetClientRect with a call to GetRectInContainer, which will obtain the coordinates of the control's rectangle relative to the container. The size of the control can then be calculated from this rectangle.

Keywords: kbbug kbfix kbdocfix kbctrlcreate kbvc500fix kbprb kbdocerr KB138664

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