本例子举例说明了在LabWindows/CVI中调用SDK函数过程中使用两种方式获得调用句柄。在LabWindows/CVI句柄的数据类型为整型，而在Windows中，句柄的类型通常为HWND类型，这就需要在使用过程中进行强制转换。

　　如果想在电脑运行时关闭显示器节电，那么可以用如下程序。

 

　　程序界面：

 

　　

 

　　程序代码：

 

#include "windows.h"
#include   
#include
#include "显示器操作.h"

static int panelHandle;

int __stdcall WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                       LPSTR lpszCmdLine, int nCmdShow)
{
 if (InitCVIRTE (hInstance, 0, 0) == 0)
  return -1; /* out of memory */
 if ((panelHandle = LoadPanel (0, "显示器操作.uir", PANEL)) < 0)
  return -1;
 DisplayPanel (panelHandle);
 RunUserInterface ();
 DiscardPanel (panelHandle);
 return 0;
}

int CVICALLBACK QuitCallback (int panel, int control, int event,
  void *callbackData, int eventData1, int eventData2)
{
 switch (event)
 {
  case EVENT_COMMIT:
   QuitUserInterface (0);
   break;
 }
 return 0;
}

//关闭按钮
int CVICALLBACK off (int panel, int control, int event,
  void *callbackData, int eventData1, int eventData2)
{
 int handle;
 switch (event)
 {
  case EVENT_COMMIT:
   
   //获得面板句柄
   GetPanelAttribute (panelHandle, ATTR_SYSTEM_WINDOW_HANDLE, &handle);
   
   //关闭显示器
   SendMessage((HWND)handle, WM_SYSCOMMAND, SC_MONITORPOWER, 2);
   break;
 }
 return 0;
}

//开启按钮
int CVICALLBACK on (int panel, int control, int event,
  void *callbackData, int eventData1, int eventData2)
{
 int handle;
 switch (event)
 {
  case EVENT_COMMIT:
   
   //获得CVI窗口句柄
   handle = GetCVIWindowHandle();
   
   //打开显示器
   SendMessage((HWND)handle, WM_SYSCOMMAND, SC_MONITORPOWER, -1);
   break;
 }
 return 0;
}