Unable to reset Ajax Combobox control at runtime

on which event you are trying to change the selected value. try to change the selected value or selected index on prerender event. i think,if you reset in page_load event, may be in combobox selected index changed event will reset to selected value. check it. try to reset at pre render event.

I've tried to set the SelectedIndex and SelectedValue in the page_load event, however it did not change the currently selected value on postback. To clarify: The first combobox changed index event is blank. I don't intend that to do anything. The second combobox throws the event which makes one of my update panels show based on the chosen criteria. My problem is the selections won't reset back to their default values when this happens.

Public Sub Page_Load(ByVal Sender As System.Object, ByVal e As System.EventArgs)
        If Page.IsPostBack Then
            TypeCB.SelectedIndex = -1
            SelectCB.SelectedIndex = -1
        End If
End Sub

                                              

1:
2:
3:
4:
5:
6:

One more addendum to this. One thing I am noticing is that the SelectedValue or Index are indeed changing the values in the background. However, the displayed values are the problem. It's almost like they're getting "stuck" in there. I have the same problem when I try to dynamically populate the second Combobox from the first with three different sets of data. Sometimes when it changes the currently selected value stays in there and causes the application to throw an error.

what it mean -1??? i think it shoul be 0

 If Page.IsPostBack Then
            TypeCB.SelectedIndex = 0
            SelectCB.SelectedIndex = 0
        End If

I dont have any .net here to check. my hope is that in page load you are reseting right??. but in changed event again it will set into original value. that means the selected value.

Yea -1 and 0 both do the same thing in this case. It's actually setting the index correctly. However the Combobox is still displaying the last selected value.

did you try to set in prerender event

I tried that, and again it did set the values but the actual visible state of the Combobox has the last selected value in it. It refuses to revert to it's default selection of "--Select--".

can you tell me, whether you are having event handler for selected index changed event on SelectCB combobox. it you have that, put the breakpoint over there and check it. In this event you put that code. through break point check the value assigned during runtime

This is the event handler for the SelectedIndexChange. I checked to make sure the values are getting set to what they're supposed to at runtime and they're indeed getting set. I've also tried adding in SelectedIndex = 0 or the Value = 0 within this event to see if it would reset the control but it only resets the values, not the actual visual state.

Protected Sub SelectCB_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles SelectCB.SelectedIndexChanged
        ResetUI()
        If TypeCB.SelectedValue = "0" Or SelectCB.SelectedValue = "0" Then
            'Enter error popup here
        Else
            If TypeCB.SelectedValue = "Assign" And SelectCB.SelectedValue = "Phone" Then
                AssignPhonePanel.Visible = True
            ElseIf TypeCB.SelectedValue = "Unassign" And SelectCB.SelectedValue = "Phone" Then
                UnassignPhonePanel.Visible = True
            ElseIf TypeCB.SelectedValue = "Assign" And SelectCB.SelectedValue = "Line" Then
                AssignLinePanel.Visible = True
            ElseIf TypeCB.SelectedValue = "Unassign" And SelectCB.SelectedValue = "Line" Then
                UnassignLinePanel.Visible = True
            Else
                'Do nothing
            End If
        End If
    End Sub

                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:

No one out there has run across this problem?