selectedindex value not being updated

[wsyeager]

I have a listbox whose autopostback property is set to 'true'. When this event fires, I have code in the 'SelectedIndexChanged' event to capture the selectedindex of the listbox to be reset on the listbox when the postback occurs. However, the selectedindex property is alway -1.

 

Below is the code prior to selecting an item for this listbox. Right after I select an item, the following code executes, which I'm expecting, but the "lstRider.SelectedIndex" value is -1, and I don't know why.......

<code>

Private Sub lstRider_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstRider.SelectedIndexChanged

 

viewstate.Item("Rider1Idx") = lstRider.Items.Item(lstRider.SelectedIndex).Value()

 

End Sub

</code>

 

Can anybody inform me how I can capture the index of the selected item in the list???

[Robby]

Is the ViewState enabled?

[wsyeager]

selectedindex not being set

 

yes, the viewsate is enabled.......

 

If I use the following code, the value of the listbox is set properly when I'm first coming into the page (NOT POSTBACK):

lstRider.SelectedIndex = lstRider.Items.IndexOf(lstRider.Items.FindByValue(CType(VIEWSTATE.Item("lngRider1UserID"), Long))) 

 

I need this value to set the item of the listbox in case the user decides to change the selected item in the listbox when the next postback occurs.

viewstate.Item("Rider1Idx") = lstRider.Items.Item(lstRider.SelectedIndex).Value()

 

However, the selectedindex is alway -1.

 

Here is the code for my pageload event:

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

DsRider1 = Cache.Get("Rider") 'ds to listbox is populated
       lstRider.DataBind()          'values appear in listbox

If Not Page.IsPostBack Then
lstRider.SelectedIndex = lstRider.Items.IndexOf(lstRider.Items.FindByValue(CType(VIEWSTATE.Item("lngRider1UserID"), Long)))
else
lstRider.SelectedIndex = lstRider.Items.IndexOf(lstRider.Items.FindByValue(CType(viewstate.Item("Rider1Idx"), Long)) 'value set in previous code snippet
end if

 

 

How am I supposed to capture the selected value of the item in the listbox?????

Edited October 15, 2003 by Volte

[PlausiblyDamp]

you will probably find that

 

DsRider1 = Cache.Get("Rider") 'ds to listbox is populated
lstRider.DataBind() 'values appear in listbox

 

is re-binding the listbox and losing the selected item - you may want to move the .DataBind bit into your PostBack chaeck.

[wsyeager]

Thanks, it was my mistake.

 

I was expecting the selectedindexchanged event to fire for the listbox BEFORE the page got posted back. It was scrwing my logic up.

 

I have the following code now and everything works fine:

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
DsRider1 = Cache.Get("Rider")
If Not Page.IsPostBack Then
lstRider.DataBind()
lstRider.SelectedIndex = lstRider.Items.IndexOf(lstRider.Items.FindByValue(CType(VIEWSTATE.Item("lngRider1UserID"), Long)))
               If lstRider.SelectedIndex > -1 Then
                   lstRider2.Enabled = True
               End If
               lstRider2.SelectedIndex = lstRider.Items.IndexOf(lstRider.Items.FindByValue(CType(VIEWSTATE.Item("lngRider2UserID"), Long)))
End if

If lstRider.SelectedIndex > -1 Then
               lstRider2.Enabled = True
               viewstate.Item("Rider1IdxUserID") = lstRider.Items.Item(lstRider.SelectedIndex).Value()
           End If
           If lstRider2.SelectedIndex > -1 Then
               viewstate.Item("Rider2IdxUserID") = lstRider2.Items.Item(lstRider2.SelectedIndex).Value()
           End If
End Sub