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

【问题】

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...

【答案】

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...

 

 

来自：https://*.com/questions/2316041/how-to-restrict-copy-paste-in-a-textbox-in-mfc