How to disallow tab key to switch focus between ed

问题:

I have dialog box having buttons and edit box.
When edit control have focus then if I press tab key it moves and focus the button.
I wanted tab key work in such a way that it will not switch focus instead it should work as tab input inside edit control i.e. input to edit box as keys.

回答1:

The solution is fairly simple, and essentially consists of handling the WM_GETDLGCODE message. This allows a control implementation to fine-tune keyboard handling (among other things).

In MFC this means:

• Derive a custom control class from CEdit.
• Add the ON_WM_GETDLGCODE message handler macro to the message map.
• Implement the OnGetDlgCode member function, that adds the DLGC_WANTTAB flag to the return value.
• Subclass the dialog's control, e.g. using the DDX_Control function.

Header file:

class MyEdit : public CEdit {
protected:
    DECLARE_MESSAGE_MAP()
public:
    afx_msg UINT OnGetDlgCode();
};

Implementation file:

BEGIN_MESSAGE_MAP(MyEdit, CEdit)
    ON_WM_GETDLGCODE()
END_MESSAGE_MAP

UINT MyEdit::OnGetDlgCode() {
    UINT value{ CEdit::OnGetDlgCore() };
    value |= DLGC_WANTTAB;
    return value;
}

回答2:

Override the PreTranslateMessage function in your dialog like this :

BOOL CTestThreadDlg::PreTranslateMessage( MSG* pMsg )
{
  if (pMsg->message == WM_KEYDOWN && pMsg->wParam == VK_TAB)
  {
    CWnd* pFocusWnd = GetFocus( );

    if (pFocusWnd != NULL && pFocusWnd->GetDlgCtrlID() == IDC_EDIT2)
    {
      CEdit *pEditCtrl = (CEdit *)pFocusWnd ;
      int start, end ;
      pEditCtrl->GetSel(start, end) ;
      CString str ;
      pEditCtrl->GetWindowText(str) ;
      str = str.Left(start) + _T("\t") + str.Mid(end) ;
      pEditCtrl->SetWindowText(str) ;
      pEditCtrl->SetSel(start + 1, start + 1) ;
    }

    return TRUE ;
  }

  return CDialog::PreTranslateMessage(pMsg) ;
}

In this example we check if the focus is in the IDC_EDIT2 edit control. You probably have to adapt this to your situation.