how to restrict copy paste in a Textbox, in MFC?

Question

I am developing a small application in MFC... there is a little problem..hope you guys would help me regarding this...Here we go..the problem is...I have 6 little edit control(Text box) in which I will allow the user to enter some numbers..I have limited the number of chars/textbox as 4 but its allowing the user to copy and paste n numbers....How do I restrict the copy paste option in an Edit control....Please help me...

Answer 1

I found 2 ways of solving the problem....please check the below...

1st method:

class CNoPasteEdit: public CEdit
{
public:
CNoPasteEdit();
~CNoPasteEdit();
protected:
// This line will need to be added by hand because WM_PASTE is not available in
// class wizard
afx_msg void OnPaste(WPARAM wParam, LPARAM lParam);
afx_msg void OnContextMenu(CWnd* pWnd, CPoint point);
DECLARE_MESSAGE_MAP()
};

Then you will need to edit the .cpp file for this class like so

CNoPasteEdit::CNoPasteEdit(){
// Put any construction code here
}

CNoPasteEdit:~:CNoPasteEdit(){
// Put any destruction code here
}

BEGIN_MESSAGE_MAP(CNoPasteEdit, CEdit)
// This line is needed because there is no default macro for WM_PASTE messages
// This line will also need to be added by hand
ON_MESSAGE(WM_PASTE, OnPaste)
ON_WM_CONTEXTMENU()
END_MESSAGE_MAP()

void CNoPasteEdit::OnPaste(WPARAM wParam, LPARAM lParam){
// Put any code here you want to execute when the user right clicks on the edit
// control. Just leave it blank to disable the menu
}

void CNoPasteEdit::OnContextMenu(CWnd* pWnd, CPoint point){
// Put any code here you want to execute when the user tries to paste into the edit
// conrtol. Just leave it blank to prevent pasting.
}

2nd method: Handle the ON_EN_CHANGE event and capture the text in the CString and check if its more than the limited character..if its..you can clear the text box with a warning message...