How to assign Telerik RadComboBox selected value to TextBox inside RadGrid Edit Form

Question

In RadGrid Edit Form template, I have a RadComboBox and a textBox. I want to assign the selected value of RadComboBox to TextBox while in RadGrid Edit Form, Is that possible. If yes, then how can one achieve this?

I can describe in picture below:

As shown in picture above, If i select comboxValue1 from RadComboBox, then it should be automatically shown in textBox Below, Is that possible in codebehinde .cs file?