这个程序可以让你在两个树控件间拖拽树节点。采用OLE技术实现，控件继承了COleDropTarget类-This procedure allows you to drag and drop between two tree control node tree. The use of OLE technology implementation, inherited control COleDropTarget category

此代码通过实现COleDropTarget类，在树控件中注册此类对象，实现了在树控件之间进行拖放接收消息的功能。-This code by implementing COleDropTarget class, registered in the tree control such objects, realized in the tree control drag and drop between the received messages.