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