Automatically Close?

Alright so I'm in Visual Basic and I have a button for a file browser to browser for a DLL to be injected. I wanted to know a way after the file has been picked to be injected how do I write code for it to be only injected to CSGO then after injected close the program automatically.

Basically, like this: Browse for DLL -> Injects to CSGO Automatically. -> Closes automatically.

Could anyone help me out with this?

if (injected)
system exit;

Application.Exit();

Enviroment.Exit();

Thats for C# though not sure about VB sorry