Microsoft KB Archive/167170

= BUG: GetWindowContextHelpId returns 0 for ActiveX Controls =

Article ID: 167170

Article Last Modified on 11/21/2006

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APPLIES TO

 Microsoft Foundation Class Library 4.2, when used with:  Microsoft Visual C++ 4.2 Enterprise Edition

 Microsoft Visual C++ 4.2 Enterprise Edition

 Microsoft Visual C++ 5.0 Enterprise Edition

 Microsoft Visual C++ 6.0 Enterprise Edition</li></ul>

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

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

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

 Microsoft Visual C++ 6.0 Professional Edition</li></ul>

 Microsoft Visual C++ 6.0 Standard Edition</li></ul> </li></ul>

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This article was previously published under Q167170

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SYMPTOMS
You can specify a control's help context ID by selecting the "Help ID" check box from the General tab of the control dialog box in resource editor. If the "Help ID" check box is selected, calling GetWindowContextHelpId at runtime retrieves the help context identifier associated with the control. This works for all standard controls, such as edit controls, button controls, etc. However, for ActiveX controls, such as TestHelp controls, Circ3 controls, and so forth, 0 is returned.

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CAUSE
MFC fails to associate a help context id for ActiveX controls even though the "Help ID" check box is selected.

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RESOLUTION
When you call SetWindowContextHelpId on the control with the correct ID, it sets the Help ID for the control. OnInitDialog is a good place to do this. For form views, OnInitialUpdate would be the best place to set the help ID. The sample code below shows a way to set and retrieve the help context ID of an ActiveX control (TestHelp control) in a CDialog-derived class.

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STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

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Sample Code
...  #include "resource.hm" // Make sure you include the .hm file // generated by the resource editor. // It includes the help ID's for the // controls. ...

BOOL CMyDialog::OnInitDialog {      CDialog::OnInitDialog;

...      // Associate a help context id with the TestHelp control. // IDC_TESTHELP_CONTROL is the id of the TestHelp control and // HIDC_TESTHELP_CONTROL is its help context id defined in      // resource.hm file. CWnd* control = GetDlgItem(IDC_TESTHELP_CONTROL); control->SetWindowContextHelpId(HIDC_TESTHELP_CONTROL);

return TRUE; // Return TRUE unless you set the focus to a control. // EXCEPTION: OCX Property Pages should return FALSE. }

void CMyDialog::MyFunction {      // Retrieve the help context id associated with the TestHelp // control. CWnd* control = GetDlgItem(IDC_TESTHELP_CONTROL); DWORD help_id = control->GetWindowContextHelpId; TRACE("Help ID for Control IDC_TESTHELP_CONTROL : %x\n", help_id); ...  } (c) Microsoft Corporation 1997, All Rights Reserved. Contributions by Yeong-Kah Tam, Microsoft Corporation

Keywords: kbbug kbnoupdate kbcshelp kbcontainer kbctrl KB167170

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