为什么服务器验证不能在我的代码中工作?

Below is the code of my simple page's submit button click. I am submitting an empty form but no server validation error messages are showing. Whats wrong with my code? Please help. WHen I click on submit, the page just turns blank and nothing happens. I am also unable to attach the debugger. When I am building my website project, it is not showing any compilation error either. I dont know what I am doing wrong.Below is the code of my simple page's submit bu