The file "Bin\debug\windowsformsapplication2.exe" is being used by another process, so the process cannot access the file.

Http://zhidao.baidu.com/question/221394579.html?qbl=relate_question_2&word=%BE%AF%B8%E6%094%09%CE%B4%C4%DC %bd%ab%22obj%5cx86%5cdebug%5c%b5%e7%d3%b0%bc%c7%c2%bc%b9%dc%c0%ed%cf%b5%cd%b3.exe%22%b8%b4%d6%c6%b5%bd%22bin% 5cdebug%5c%b5%e7%d3%b0%bc%c7
Obviously this is because you have just run the program in debug mode!
And then you simply click on the x to turn it off, which shows a problem,
Your program in the exit code part of the problem, causing yourself to point X to turn off the interface after the process has not been finished!
So when you're going to build the EXE for the second time because the process that started generating that EXE is running, it can't be written!
It is recommended that you add the code of the release process to the End function of the program. Of course, you will need to find the process Manager to WindowsFormsApplication2.exe and end it before you can regenerate the program.

Http://zhidao.baidu.com/link?url=05DrgqcB7yFsApyaXmuitG4LY1uVjqc8dMyMm3xybMq3fR-Q6RBu01-T-5BWTXCigUoupPzyCDxkuRlCecPLyK
This statement indicates that the WindowsFormsApplication9.exe you generated is still running, not completely closed, and may be caused by:
1. Use this. Hide (); Hides the form instead of actually closing the form.
2. The form is not closed.
Workaround:
1. Use Application.exit () in the right place; close all processes of the program.
2. Open Task Manager and manually end WindowsFormsApplication9.exe this process
3. Restart the computer (tried, effective)

The file "Bin\debug\windowsformsapplication2.exe" is being used by another process, so the process cannot access the file.