System.Web.HttpException: A DropDownList cannot have multiple items selected

[DC Gringo]

I'm having such a problem with this DropDownList in a user control that is
posting back and throwing an error: System.Web.HttpException: A
DropDownList cannot have multiple items selected

<ASPROPDOWNLIST ID="lbCountriesWiz" ENABLEVIEWSTATE="true" FONT-SIZE="8pt"
ONSELECTEDINDEXCHANGED="ddlQueryProvinces"
AUTOPOSTBACK="True" RUNAT="server" WIDTH="150px"></ASPROPDOWNLIST>


Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
'Put user code to initialize the page here

If Not Page.IsPostBack Then

Dim tempItem3 As New System.Web.UI.WebControls.ListItem
tempItem3.Text = "Chad"
tempItem3.Value = "TD"
tempItem3.Selected = False
Me.lbCountriesWiz.Items.Insert(0, tempItem3)

Dim tempItem2 As New System.Web.UI.WebControls.ListItem
tempItem2.Text = "Bosnia and Herzegovina"
tempItem2.Value = "BA"
tempItem2.Selected = False
Me.lbCountriesWiz.Items.Insert(0, tempItem2)

Dim tempItem As New System.Web.UI.WebControls.ListItem
tempItem.Text = "|--None Selected"
tempItem.Value = "0"
tempItem.Selected = False
lbCountriesWiz.Items.Insert(0, tempItem)

End If

End Sub



When a button in the same user control is pushed and then I reselect the
DropDownList, I don't get the error.

<ASP:BUTTON ID="btnAllCommunities"
ONCLICK="btnPopulateAllCommunities_OnClick" FONT-SIZE="8"
RUNAT="server" TEXT="All Communities" BORDERSTYLE="inset"></ASP:BUTTON>

Public Sub btnPopulateAllCommunities_OnClick(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles btnAllCommunities.Click

'These simply fill some other listboxes

GetProvinces()
GetDistricts()
GetSubDistricts()
GetCommunities()

End Sub





When buttons (such as below) in the controling Page are pushed and then I
try to reselect the DropDownList, I get the error.

<ASP:BUTTON id="btn1" onclick="GetReport1_OnClick" RUNAT="server" TEXT="Get
report of" HEIGHT="20"
FONT-SIZE="10px"></ASP:BUTTON>

Sub GetReport1_OnClick(ByVal Sender As Object, ByVal e As System.EventArgs)

Try

dgSHA.Visible = False
dgShasSum.Visible = False
dgCommunity.Visible = True
dgCommunitiesSum.Visible = True


ShowButtons()




'pnlCommunitiesButtons.Visible = True

Dim _sqlStmtR1 As String
_sqlStmtR1 = "SELECT * FROM vwCommunities WHERE countryID = '" &
CType(Page,
_default1).chooseAdminUnitsWiz1.lbCountriesWiz.SelectedItem.Value & "' "

If ddlImpactLevel1.SelectedItem.Value <> "All" Then
_sqlStmtR1 = _sqlStmtR1 & " AND Impact = '" &
ddlImpactLevel1.SelectedItem.Value & "'"
End If
'_sqlStmtR1 = _sqlStmtR1 & " ORDER BY Community"

Dim myDataSetCommunities1 As New DataSet
Dim myDataAdapterCommunities1 As New SqlDataAdapter(_sqlStmtR1,
connection1.conString)
myDataAdapterCommunities1.Fill(myDataSetCommunities1,
"CommunitiesTmp1")
dgCommunity.DataSource =
myDataSetCommunities1.Tables("CommunitiesTmp1")
dgCommunity.DataBind()

CommunitiesWizSqlSumStatement(1)

Dim myDataSetCommunitiesSum As New DataSet
Dim myDataAdapterCommunitiesSum As New
SqlDataAdapter(_sqlStmtLbCommunitiesWizSum, connection1.conString)
myDataAdapterCommunitiesSum.Fill(myDataSetCommunitiesSum,
"CommunitiesSumTmp1")
dgCommunitiesSum.DataSource =
myDataSetCommunitiesSum.Tables("CommunitiesSumTmp1")
dgCommunitiesSum.DataBind()


RecordCount2.Text = ""
RecordCount3.Text = ""
RecordCount4.Text = ""
RecordCount5.Text = ""
RecordCount6.Text = ""

Dim RcdCount As Integer
Dim ResultCount As Integer
RcdCount =
myDataSetCommunities1.Tables("CommunitiesTmp1").Rows.Count.ToString()
ResultCount = RcdCount
RecordCount1.Text = RcdCount & " records"
RecordCountBottom.Text = RcdCount & " records"

Session("savedDataGridSql") = _sqlStmtR1
Session("dgType") = "Community"
Me.sortCriteria = "Community"
Me.sortDir = "ASC"
If Session("dgType") = "Community" Then
pnlCommunitiesButtons.Visible = True
pnlShasButtons.Visible = False
Else
pnlCommunitiesButtons.Visible = False
pnlShasButtons.Visible = True
End If




Catch ex As Exception
ExceptionManager.Publish(ex)
End Try


End Sub

 

[Karl Seguin]

You've shown a lot of code, too much and too spread out to be too useful.
But the error speaks for itself, somewhere you are setting two selected
values to the dropdown and this isn't allowed. My guess is that it's
beeing set in the Page_Load and being set elsewhere on one of the many
button postbacks.... You'll simply need to debug and/or simplify your code
to get to the root of it.

Karl