Closing if/else statement

I have a problem. I made function and i want to activate it on form closing. I know that it's possible to do that on Form.Closing but, it doesn't detect function on "current context" and i tried to make it on if else statement, but there's a lot of errors. Here's the code:

if (this.Close = true)
{
    Process.Start(process);
} 

My fifth probe and it still doesn't work. Pls Help.