PRB: Accelerator Keys Fail with ATL Control on a VB UserControl

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 6.0
• Microsoft Visual C++, 32-bit Editions, version 6.0

SYMPTOMS

If an ActiveX Template Library (ATL) control created with Visual C++ 6.0 is placed directly on a Visual Basic form, the accelerator keys will work correctly. However, if the control is first placed inside a Visual Basic Usercontrol and the usercontrol is then placed on a form, the accelerator keys will not work.

CAUSE

This is due to the ATL control not giving the composite control the chance to handle the accelerator keys.

RESOLUTION

Explicitly forward the message to the composite control.

MORE INFORMATION

Steps to Reproduce Behavior

Steps to Create an ATL Control with Visual C++ 6.0

1. Open the Microsoft Visual C++ 6.0 integrated development environment (IDE) and select New from the File menu. In the New dialog box, select the Projects tab and then choose "ATL COM AppWizard" from the list of project types. Type "MyEditCtl" in the Project name text box and then click OK. Click Finish in the ATL COM AppWizard dialog box and then click OK in the next dialog box that displays. You have just created an ATL project.



2. In the class view of the project, right-click "MyEditCtl Classes" and select New ATL Object from the drop-down box. The ATL Object Wizard dialog box displays. Click controls from the Category list box and then choose Full Control from the Objects list box. Click Next. Type "MyCtl" in the "short name" text box. Click the Miscellaneous tab and then select Edit from the "Add control based on" combo box and then click OK. A new control is added to your ATL project.



3. Build the project by selecting Build MyEditCtl.dll from the Build menu. The control will be automatically registered.

Steps to Create Visual Basic Client

1. Create a standard EXE project with Visual Basic 6.0. Form1 is created by default.



2. Select Components from the Projects menu. Select MyEditCtl 1.0 Type Library from the list and then click OK. You should now see that MyCtl has been added to the toolbox.



3. Select Add User Control from the Projects menu and then click open in the Add User Control dialog box.



4. Add "MyCtl" to the user control. Close the user control design window.



5. Open the Form1 design window. Place "MyCtl" and the user control that you just created onto Form1.



6. Press F5 to run the application. Type some characters into both of the MyCtl controls. If you press the arrow keys in the MyCtl that is directly on the form, they work as expected. However, if you use the arrow keys in the MyCtl that is contained within the user control, it will move the focus to another control.



7. Save and close the Visual Basic project.

Steps to Resolve the Problem

1. Open the ATL project. In the Class view, expand CMyCtl and then double-click "PreTranslateAccelerator(LPMSG pMsg, HRESULT& hRet)". Now MyCtl.h is opened in the editor window.



2. Replace the PreTranslateAccelerator function with the following code:

   
      BOOL PreTranslateAccelerator(LPMSG pMsg, HRESULT& hRet)
      {
         if(pMsg->message == WM_KEYDOWN && 
            (pMsg->wParam == VK_LEFT || 
            pMsg->wParam == VK_RIGHT ||
            pMsg->wParam == VK_UP ||
            pMsg->wParam == VK_DOWN))
         {
            hRet = S_OK; 
            m_ctlEdit.SendMessage(pMsg->message, pMsg->wParam, pMsg->lParam);
            return TRUE;
         }
         //TODO: Add your additional accelerator handling code here
         return FALSE;
      } 




3. Rebuild the project.

REFERENCES

For additional information on problems using ATL controls on Visual Basic forms, please see the following articles in the Microsoft Knowledge Base:

Q187644 ATL Controls Fail to Recognize Default Button on VB Form

Q179696 PRB: Focus and Tab Issues with ATL Subclassed Edit Control

Additional query words:

Keywords          : kbsample kbwizard kbActiveX kbATL kbCtrlCreate kbVBp600 kbVC600 kbGrpVB 
Version           : WINDOWS:6.0; winnt:6.0
Platform          : WINDOWS winnt 
Issue type        : kbprb 

Last Reviewed: June 1, 1999