通过本程序，你将了解到以下相关内容：

　　改变计算机在网络中的名字；

　　创建源设备环境；

　　创建和SourceDC兼容的目标设备环境；

　　创建一个和SourceDC兼容的内存设备环境，并返回其设备句柄；

　　抓图并释放设备环境；

　　 在某些情况下，我们编写的应用程序同时只能有一个实例在内存中运行，例如服务器程序、需要独占某设备的程序，甚至我们仅仅是让程序同时只有一个实例运行。要实现此功能，需要在程序中加一点判断的代码。

　　再工程文件里面， Application.Initialize 前面加上判断就可以了，注意了，必须得加一个Windows单元，才能运行。

-Through this program, you will learn the following related content:

Change the name of the computer in the network

Create the source device context

Create and SourceDC compatible target device environment

Creating a SourceDC compatible memory device, and returns its handle to the device

Drawings and release the device context

In some cases, we also prepared an application can have only one instance running in memory, such as server program needs to independence

Accounting procedures for a device, even while we just let the program run only one instance. To achieve this feature, add one point in the program need to determine

Code.

Re-engineering documents which, Application.Initialize　preceded by judgments on it, pay attention, and have to add a Windows

Unit, to run.