说明： C#知识库是在学习C#时积累的一些知识。本软件用C#编写,运行需要Microsoft .NET框架支持。打开树状节点，双击可查看知识 (C# knowledge library is when studies C#
accumulates. This software compiles with C#, the movement needs the
Microsoft NET frame support. Opens the tree shape pitch point,
double-clicks may examine the knowledge )
