按下按钮时，Visual Basic 2013在文本框中显示sql select

In my project, I have a disabled textbox, which i would like to return me a value from a database when i click on a button, the problem is that I don't really know the code in order to do this. I've tried some tutorials here, but no one explains how to return a value when a button is pressed. My code is pretty much this: In my project, I have a disabled textbox, which