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Using a Context Menu on a Control
 

Introduction

One of the primary characteristics of a control is to make its role appear obvious to the user. For example, by default, a button is used to click in order to start an action. Sometimes you may want to display a context menu. That is, if the user right-clicks, instead of a (left) click, you may want to display a particular menu. Many MFC controls don't provide this functionality on their own; you would have to apply the action on the parent control.
  1. Start Microsoft Visual C++ MFC Application named ControlContext
  2. Create it as Dialog Box without the AboutBox
  3. Set the Dialog Title to Context-Sensitive Menu on Controls
  4. Add a button to dialog box. Change its ID to IDC_SUBMIT_BTN and its Caption to Submit
  5. Add a check box to the dialog box. Change its ID to IDC_APPROVED_CHK and its Caption to Approved:
     
  6. Display the Add Resource dialog box and double-click Menu
     
  7. Change the ID of the IDR_MENU1 to IDR_SUBMIT and create it as follows:
     
  8. Set their IDs to ID_POPUP_GREEN, ID_POPUP_RED, ID_POPUP_YELLOW, ID_POPUP_BLUE, ID_POPUP_WHITE, and ID_POPUP_FUCHSIA
  9. Display the dialog box and click its body
  10. In the Properties window, click the Messages button
  11. Click the arrow of the WM_CONTEXTMENU combo box and implement the event as follows:
      
    void CControlContextDlg::OnContextMenu(CWnd* /*pWnd*/, CPoint point)
{
	// TODO: Add your message handler code here
	// Load the desired menu
	CMenu mnuPopupSubmit;
	mnuPopupSubmit.LoadMenu(IDR_SUBMIT);

	// Get a pointer to the button
	CButton *pButton;
	pButton = reinterpret_cast<CButton *>(GetDlgItem(IDC_SUBMIT_BTN));

	// Find the rectangle around the button
	CRect rectSubmitButton;
	pButton->GetWindowRect(&rectSubmitButton);

	// Get a pointer to the first item of the menu
	CMenu *mnuPopupMenu = mnuPopupSubmit.GetSubMenu(0);
	ASSERT(mnuPopupMenu);
	
	// Find out if the user right-clicked the button
	// because we are interested only in the button
	if( rectSubmitButton.PtInRect(point) ) // Since the user right-clicked the button, display the context menu
		mnuPopupMenu->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, point.x, point.y, this);
}
  12. On the dialog box, double-click the Submit button and implement its Click event as follows:
      
    void CControlContextDlg::OnBnClickedSubmitBtn()
{
	// TODO: Add your control notification handler code here
	AfxMessageBox("You clicked the Submit button but ain't nothin' to do right now!!!");
}
  13. Display the IDR_SUBMIT menu
  14. Right-click the Green menu item and click Add Event Handler...
  15. Set the Class List to CControlContextDlg
  16. Display the IDR_SUBMIT menu
  17. Right-click the Red menu item and click Add Event Handler
  18. Set the Class List to CControlContextDlg
  19. Implement both events as follows:
      
    void CControlContextDlg::OnPopupGreen()
{
	// TODO: Add your command handler code here
	AfxMessageBox("You selected the Green menu item");
}

void CControlContextDlg::OnPopupRed()
{
	// TODO: Add your command handler code here
	AfxMessageBox("You selected the Red menu item");
}
  20. Execute the application and right-click the Submit button:
     
  21. Right-click the Approved check box or one of the other buttons of the dialog box and notice that no context menu appears
  22. Close the dialog box and return to MSVC
  23. Display the Add Resource dialog box again. Click Menu and click Add
  24. Change the menu's ID to IDR_APPROVAL and design it as follows:
     
  25. To be able to display the other menu, change the OnContextMenu() event as follows:
      
    void CControlContextDlg::OnContextMenu(CWnd* /*pWnd*/, CPoint point)
{
	// TODO: Add your message handler code here
	// Load the desired menu
	CMenu mnuPopupSubmit;
	CMenu mnuPopupApproval;

	mnuPopupSubmit.LoadMenu(IDR_SUBMIT);
	mnuPopupApproval.LoadMenu(IDR_APPROVAL);

	// Get a pointer to the button
	CButton *pButton, *chkApproval;

	pButton = reinterpret_cast<CButton *>(GetDlgItem(IDC_SUBMIT_BTN));
	chkApproval = reinterpret_cast<CButton *>(GetDlgItem(IDC_APPROVED_CHK));

	// Find the rectangle around the control
	CRect rectSubmitButton, rectApprovalButton;

	pButton->GetWindowRect(&rectSubmitButton);
	chkApproval->GetWindowRect(&rectApprovalButton);

	// Get a pointer to the first item of the menu
	CMenu *mnuPopupMenu = mnuPopupSubmit.GetSubMenu(0);
	CMenu *mnuPopupMenu2 = mnuPopupApproval.GetSubMenu(0);
	ASSERT(mnuPopupMenu);
	ASSERT(mnuPopupApproval);
	
	// Find out if the user right-clicked a button
	if( rectSubmitButton.PtInRect(point) ) // Since the user right-clicked a button, display its context menu
		mnuPopupMenu->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, point.x, point.y, this);
	else if( rectApprovalButton.PtInRect(point) )
		mnuPopupMenu2->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, point.x, point.y, this);
}
  26. Display the IDR_APPROVAL menu
  27. Right-click each menu item and click Add Event Handler. Set the Class List to CContextMenuDlg
  28. Implement the events as follows:
      
    void CControlContextDlg::OnPopupUnderreview()
{
	// TODO: Add your command handler code here
	CheckDlgButton(IDC_APPROVED_CHK, BST_INDETERMINATE);
}

void CControlContextDlg::OnPopupApproved()
{
	// TODO: Add your command handler code here
	CheckDlgButton(IDC_APPROVED_CHK, BST_CHECKED);
}

void CControlContextDlg::OnPopupRejected()
{
	// TODO: Add your command handler code here
	CheckDlgButton(IDC_APPROVED_CHK, BST_UNCHECKED);
}
  29. Test the application
   
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