屏蔽编辑框的右键菜单

开发中，经常需要对一些编辑框作输入限制，如限制只能输入0..9的数字，这通过OnKeyPress事件即可达到：if not (Key in ['0'..'9', #8]) then Key := #0; 但是这只能限制键盘输入，对通过鼠标右键粘贴的情况就无法进行限制啦。下面的代码是通过对编辑框进行subclass而过滤掉WM_CONTEXTMENU右键菜单消息，从而达到屏蔽右键菜单。

var
  FHookCtrls: TStringList;
{ 截获过滤编辑框Edit弹出右键菜单消息WM_CONTEXTMENU }

function EditWndProc(hwnd: HWND; Msg: UINT; WParam: WPARAM; LParam: LPARAM): LRESULT; stdcall;
var
I: Integer;
begin
if Msg = WM_CONTEXTMENU then
Result := 1
else
begin
I := FHookCtrls.IndexOf(IntToStr(hwnd));
if I >= 0 then
Result := CallWindowProc(Pointer(FHookCtrls.Objects[I]),
hwnd, Msg, WParam, LParam)
else
Result := 1;
end;
end;
{ 添加对编辑框Edit弹出右键菜单消息WM_CONTEXTMENU的过滤 }

procedure HookControl(const Control: array of TWinControl);
var I, X: Integer;
begin
for X := Low(Control) to High(Control) do
begin
I := FHookCtrls.Add(IntToStr(Control[X].Handle));
FHookCtrls.Objects[I] := Pointer(GetWindowLong(Control[X].Handle, GWL_WNDPROC));
SetWindowLong(Control[X].Handle, GWL_WNDPROC, Longint(@EditWndProc));
end;
end;
{ 取消对编辑框Edit弹出右键菜单消息WM_CONTEXTMENU的过滤 }

procedure UnhookControl(const Control: array of TWinControl);

var

  I, X: Integer;

begin

  for X := Low(Control) to High(Control) do

  begin

    I := FHookCtrls.IndexOf(IntToStr(Control[X].Handle));

    if I >= 0 then

    begin

      SetWindowLong(Control[X].Handle, GWL_WNDPROC, Longint(FHookCtrls.Objects[I]));

      FHookCtrls.Delete(I);

    end;

  end;

end;

initialization

  FHookCtrls := TStringList.Create;

  FHookCtrls.Sorted := True;

finalization

  FHookCtrls.Free;

end.

来源：http://www.delphibbs.com/keylife/iblog_show.asp?xid=17224