第二种:通过枚举所有窗口,查询特定条件的窗口
function EnumWindowsProc(Wnd: HWND; Param: Integer): Boolean; stdcall;
var
cn : Array[0..255] of char;
tab : HWND;
tId : DWORD;
begin
 Result := TRUE;
 if GetClassName(wnd, cn, 255) > 0 then
  if cn = '#32770' then
   begin
    if (FindWindowEx(wnd, 0, 'Button','新建窗口') <> 0) and
       (FindWindowEx(wnd, 0, 'Button','拨打电话') <> 0) and
       (FindWindowEx(wnd, 0, 'Button','发送(Enter)') <> 0) then
    begin
     tID := GetWindowThreadProcessID(wnd, nil);
     Form1.Memo1.Lines.Add('对话框句柄：'+IntToStr(Wnd));
     Form1.Memo1.Lines.Add('对话框线程ID：' + IntToSTr(tID));
    end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
EnumWindows(@EnumWindowsProc,0);
end;

第三种: 查找字窗口内元素的句柄
FindWindowEx(wnd, 0, 'Button','拨打电话')