Ok, before I give you how to do this, please read some of the tutorials, explorer MSDN and learn some basics on the coding of ASP.Net pages. Trust me even if you don't understand it all, it will begin to make sense the more you use/apply that knowledge.
Here is the pseudo-code to do what you asked: (**note: You can do this in one line of code, that fires when you select something different in the dropdownlist, but it requires one property parameter to be changed, and doesn't require a button. But I will let you figure that out. )
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Put user code to initialize the page here
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
lblResult.Text = cboValue.SelectedItem.Text
Hope this helps
Then ask that in another thread, or forum. You don't need databinding to accomplish that task (nor do you even need ASP.NET or any server-side code).