processing through reloading webpage

[dualshock03]

I need a help in ASP.NET,, the situation is,, i have a login page then a drop down box is placed in order to select the corresponding user if he's an administrator or a client user... upon selecting an administrator word in the dropdown control.. the security ID textbox will be in enabled = true state... but the problem is, the code that i created doesnt work which should be in vb.net... it only work if i press the login button..

here's the code:
' this code is executed after loading the log-in page and the user selects from the dropdown control'

Protected Sub dropchoose_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles dropchoose.SelectedIndexChanged


If dropchoose.SelectedIndex = 1 Then
securityIDtxtbx.enabled = False

Else
securityIDtxtbx.enabled = True
End If
End Sub
reponse for any clarification

 

[Harsh Gupta]

Selecting a value from DropDownList doesn't postback the form until you set the AutoPostBack property of DropDownList to True.