普通的窗口需要按住标题栏才可以拖动；有些程序，比如QQ2007的主窗口，按住空白处就可以了。这个类提供了这种功能，你只需要提供用户鼠标按下的控件和你想要拖动的控件。一般来说这两者是一致的，比如都是主窗体，效果就是：按住主窗体就可以拖着它走。但是你也可以选择不同的控件，程序里示例了3种情况。

程序开发环境是VS.net2005-General need to hold down the window before they can drag the title bar　some procedures, such as QQ2007 the main window, press and hold the blank space on it. This class provides this functionality, you only need to provide the user pressed the mouse controls and the controls you want to drag. Generally speaking these two are consistent, for example, are the main form, the effect is that: hold down the main form can be dragged it away. But you can also choose a different control, program examples of the three kinds of situation. Program development environment is VS.net2005