点击鼠标和用鼠标勾选鼠标有什么区别？

Assuming you're referring to WinForm Control events, from the MSDN documentation for Control.Click:

The Click event passes an EventArgs to its event handler, so it only indicates that a click has occurred. If you need more specific mouse information (button, number of clicks, wheel rotation, or location), use the MouseClick event. However, the MouseClick event will not be raised if the click is caused by action other than that of the mouse, such as pressing the ENTER key.

A click can be caused by not only a mouse click, but also some events like a pressed key, etc. For more information, see Control.Click Event.