刚开始准备参考一个IP输入控件来编写，感觉有点复杂，因为它是从TWinControl继承的。我的控件还不需要那么复杂，刚开始准备从TEdit来继承，不过看了一下TEdit的源代码，就是把TCustomEdit的所有属性published，没有其它的操作。于是我也决定从TCustomEdit继承。-The beginning of a ready reference to the preparation of IP input control, I feel a bit complicated, because it is inherited from the TWinControl. I do not need the controls are so complex prepared from the beginning to the succession of TEdit, but look at the source code TEdit is to TCustomEdit all the attributes published, no other operation. So I decided to inherit from TCustomEdit.