Hello (again)

I have a text box that i am trying to put the value of a selected item of a dropdown list in...

Protected Sub ddlCell_SelectedIndexChanged(sender As Object, e As System.EventArgs) Handles ddlCell.SelectedIndexChanged

        Dim reply As String = ddlCell.SelectedValue

        txtCheck.Text = reply

    End Sub

but when i select something in the list it doesnt appear in the text box.

I am using the same code on a button click and that does work.

why is this?