On my web form I have a textbox control (jobno) and a dropdown list
(DD_costcode). The values that are populated into the dropdown list
are based on what is keyed into the textbox. When I key a value into
my textbox the values populate in my dropdown list and the first value
in the dropdown list appears. This works great. What I can't get to
work is if a user goes back to the textbox control and deletes the
value in there I need the dropdown list to clear out the previous
values and just be blank.
I've tried using an textchanged event handler on my textbox control
and set the dropdown list value to nothing when the textbox value is
empty but that didn't work and then I tried setting the dropdown value
to "" but that gives me an error that the dropdown list selected value
is invalid because it is not in the list.
Does anyone know how I can set the value to blank in my dropdown
list?
Here is my event handler code (DD_costcode is my dropdown list).
Protected Sub Jobno_TextChanged(ByVal sender As Object, ByVal e As
System.EventArgs) Handles jobno.TextChanged
If jobno.Text = Nothing Then
GLAcct.Enabled = True
GLAcct.BackColor = Drawing.Color.White
DD_CostCode.SelectedValue = Nothing
Else
GLAcct.BackColor = Drawing.Color.Gray
GLAcct.Enabled = False
End If
End Sub
