Dropdownlist goes to first record on PostBack

[bubberz]

I have two dropdownlists. The second is populated from the first ddl selection, hence the record selection is filtered via the first ddl to the second ddl.
I need to have Postback on the second to populate a third ddl. If I select the third item in the second ddl, the postback happens and this ddl goes back to the first record, and doesn't stay @ the third selected item.

I build this second ddl first in:
Page_Load
If (Not Page.IsPostBack).....

I also re-build this second ddl in:
Page_PreRender
Dim sqlGrp As String
sqlGrp = "SELECT GC+' - '+GD as Expr2, GC,GD, "
sqlGrp &= "DC FROM [RL-DG] WHERE "
sqlGrp &= "DC = " & " '" & ddlDivision.SelectedValue.ToString() & "'"
Dim cmdGrp As New OleDbCommand(sqlGrp, Con1)
Con1.Open()
Dim myRDR As OleDbDataReader = cmdGrp.ExecuteReader()
If myRDR.HasRows = True Then
ddlGroup2.DataSource = myRDR
ddlGroup2.DataTextField = "Expr2"
ddlGroup2.DataValueField = "GD"
ddlGroup2.DataBind()
End If
Con1.Close()

Any suggestion would be much appreciated!
Thanks!

 

[checkai]

first off...are all your ddl's enabledviewstate = true?


page load
if not page.ispostback then
Load first ddl
end if


Private Sub ddl1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddTypes.SelectedIndexChanged
load ddl2 based on this selection
End Sub

Private Sub ddl2_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddTypes.SelectedIndexChanged
load ddl3 based on this selection
End Sub

"...we both know I'm training to become a cagefighter...see what happens if you try 'n hit me..."

 

[bubberz]

Hey checkai!
Yes, they are both set to enableviewstate="true"

I tried your suggestion, and still have the second ddl, ddlGroup2, resetting back to the first option and not keeping it's selected value when it's doing a PostBack.
I'm now trying the following code:

Private Sub Page_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.PreRender
Dim sDiv As String = ""
Dim sGrp As String = ""
Dim sRes As String = ""

If ddlDivision.SelectedIndex > -1 Then
sDiv = ddlDivision.SelectedValue
End If

If ddlGroup.SelectedIndex > -1 Then
sGrp = ddlGroup2.SelectedValue
End If

If ddlResource.SelectedIndex > -1 Then
sRes = ddlResource.SelectedValue
End If

Dim sqlGrp As String = "SELECT GC+' - '+GD as Expr2, GC, GD, "
sqlGrp &= "DC FROM [RL-DivG]"

If Not sDiv = Nothing Then
sqlGrp = sqlGrp & " WHERE DC ='" & sDiv & "' "
End If
If Not sGrp = Nothing Then
sqlGrp = sqlGrp & " and GD ='" & sGrp & "' "
End If

Dim cmdGrp As New OleDbCommand(sqlGrp, Con1)
Con1.Open()
Dim myRDR As OleDbDataReader = cmdGrp.ExecuteReader()
If myRDR.HasRows = True Then
ddlGroup2.DataSource = myRDR
ddlGroup2.DataTextField = "Expr2"
ddlGroup2.DataValueField = "GD"
ddlGroup2.DataBind()
End If
Con1.Close()

SelectListBoxValue(ddlDivision, sDiv)
SelectListBoxValue(ddlGroup2, sGrp)
SelectListBoxValue(ddlResource, sRes)

lblDiv.text = GetListBoxValue(ddlDivision, "Unknown")
lblGrp2.text = GetListBoxValue(ddlGroup2, "Unknown")
lblRes.text = GetListBoxValue(ddlResource, "Unknown")

End Sub

Private Sub SelectListBoxValue(ByRef MylistBox As Object, ByVal MyVal As Object)
Dim obj As DropDownList = CType(MylistBox, DropDownList)
Dim v As String = CStr(MyVal)

If Not v = Nothing Then v = v.ToLower
Dim i As Integer
For i = 0 To obj.Items.Count - 1
If CType(obj.Items(i), ListItem).Value.ToLower = v Then
obj.SelectedIndex = i
Exit For
End If
Next
End Sub

Private Function GetListBoxValue(ByVal obj As Object, Optional ByVal sDefaultValue As Object = "") As Object
If obj.SelectedIndex = -1 Then Return sDefaultValue
'Return obj.SelectedItem.Value
Return obj.items(obj.SelectedIndex).value
End Function