I get the following in my error message:
[NullReferenceException: Object reference not set to an instance of an
object.]
ASP.rfiAccess_aspx.GetContractSelectedIndex(String contract_id) +45
ASP.rfiAccess_aspx.__DataBind__control18(Object sender, EventArgs e) +141
"clickon" wrote:
[color=blue]
> Does the error message not say something like below with the line that is
> causing the error highlighted ?
>
> Exception Details: System.NullReferenceException: Object reference not set
> to an instance of an object.
>
> Source Error:
>
>
> Line 228: For i As Integer = 1 To 35
> Line 229: field = "Q" + CStr(i)
> Line 230: score.ID = "txtQ" + CStr(i)
> Line 231: If Not
> IsDBNull(ds.Tables("mmsSpecRecord").Rows(0)(field) ) Then
> Line 232: score.Text =
> ds.Tables("mmsSpecRecord").Rows(0)(field)
>
>
> Source File: c:\inetpub\wwwroot\Demo\displayMMS.aspx.vb Line: 230
>
> "glenn" wrote:
>[color=green]
> > Thanks for your reply.
> >
> > The problem occurs when I call the GetContractChoice ( ) function and the
> > GetContractSelectedIndex function from the <asp:DropDownList ...> in the
> > html. Not sure exactly what line as I need to block out chunks of code to
> > get the page to run without errors.
> >
> > My Update statement and Param defintions are as follows. The problem may
> > occur in these lines.
> >
> > "UPDATE rfi SET question =@questionParam, contract =@contractParam, ***ALOT
> > OF OTHER FIELDS*** WHERE id =@IDParam"
> >
> > ' CONTRACT PARAM IS DEFINED AS FOLLOWS
> > Dim contractParam as IDataParameter = New
> > OleDbParameter("@contractParam", OleDbType.varchar, 50)
> > contractParam.Value = ddlContracts.SelectedIndex
> > dbCommand.Parameters.Add(contractParam)
> >
> >
> >
> > "clickon" wrote:
> >[color=darkred]
> > > What line in the code is causing the error?
> > >
> > > "glenn" wrote:
> > >
> > > > Hi folks,
> > > >
> > > > I am getting an error "Object reference not set to an instance of an object".
> > > >
> > > > It seems I have everything in place but something is obviously in err. If
> > > > you could take a quick peak at my code segments and provide any insight in a
> > > > reply, I would be eternally grateful. My table name is "rfi" and the field
> > > > with a dropdownlist control is called "contract". I have imported the
> > > > System.Data and System.Data.OleDb libraries. Currently I am running the page
> > > > with a local web server. If I run the page without the reference to the
> > > > contract field with its associated functions, it works fine. A question
> > > > field is shown only as an example field and is not the problem. All code
> > > > referencing the contract field may be causing my problem.
> > > >
> > > > ' GLOBAL VARIABLE
> > > > Dim ddlContractDataSet as DataSet = New DataSet ( )
> > > >
> > > > ' UPDATE ROW CODE SNIPPET
> > > > Sub DataGrid1_UpdateRow (sender As Object, e As DataGridCommandEventArgs)
> > > > If Not Page.IsValid Then Exit Sub
> > > >
> > > > ' GET INFO FROM FIELDS
> > > > Dim questionTextBox as TextBox = e.Item.Cells (1).FindControl
> > > > ("txtQuestion") ' THIS LINE WORKS FINE AND IS SHOWN ONLY AS AN EXAMPLE
> > > > Dim ddlContracts as DropDownList = e.Item.Cells (2).FindControl
> > > > ("ddlContract")
> > > > ...... ' OTHER FIELDS
> > > >
> > > > ' PROVIDE A SQL UPDATE STATEMENT
> > > > ' PROVIDE A CONNECTION STRING AND A CONNECTION
> > > > ' PROVIDE A dbCOMMAND with COMMANDTEXT=SQL STATEMENT AND A
> > > > dbCONNECTION=CONNECTION
> > > > ' DECLARE A PARAMETER
> > > > Dim contractParam as IDataParameter = New OleDbParameter
> > > > ("@contractParam", OleDbType.varchar, 50)
> > > > contractParam.Value = ddlContracts.SelectedIndex
> > > > dbCommand.Parameters.Add (contractParam)
> > > > End Sub
> > > >
> > > > ' PROVIDE FUNCTION TO POPULATE DROPDOWNLIST FROM DB
> > > > Function GetContractChoice( ) As DataSet
> > > > Dim strConnString As String = "Provider=Microsoft.Jet.OLEDB.4.0; Ole
> > > > DB Services=-4; Data Source=C:\FDMgmt\webfiles\database\fdmdb.mdb"'
> > > > Dim dbConnection As IDbConnection = New OleDbConnection(connectionString)
> > > > Dim queryString As String = "SELECT [rfi].[contract] FROM [rfi]"
> > > >
> > > > Dim dbCommand As IDbCommand = New OleDbCommand
> > > > Dim dbConnection As IDbConnection = New OleDbConnection(strConnString)
> > > >
> > > > dbCommand.CommandText = queryString
> > > > dbCommand.Connection = dbConnection
> > > >
> > > > Dim dataAdapter As IDbDataAdapter = New OleDbDataAdapter
> > > > dataAdapter.SelectCommand = dbCommand
> > > > dataAdapter.Fill(ddlContractDataSet)
> > > >
> > > > Return ddlContractDataSet
> > > > End Function
> > > >
> > > > ' PROVIDE FUNCTION TO GET THE SELECTED ITEM
> > > > Function GetContractSelectedIndex(contract_id as String) as Integer
> > > > Dim iLoop as Integer
> > > > Dim dt as DataTable = ddlContractDataSet.Tables("rfi")
> > > >
> > > > For iLoop = 0 to dt.Rows.Count - 1
> > > > if contract_id = dt.Rows(iLoop)("ID").ToString() then
> > > > Return iLoop
> > > > end if
> > > > Next iLoop
> > > > End Function
> > > >
> > > > ' PROVIDE DATAGRID INFO IN THE HTML
> > > > <asp:DataGrid id="DataGrid1" runat="server"
> > > > OnItemDataBound="DataGrid1_RowDataBound"
> > > > OnDeleteCommand="DataGrid1_DeleteRow" DataKeyField="ID"
> > > > OnCancelCommand="DataGrid1_CancelRow" OnUpdateCommand="DataGrid1_UpdateRow"
> > > > OnEditCommand="DataGrid1_EditRow" OnSortCommand="DataGrid1_Sorting"
> > > > AllowSorting="True" OnPageIndexChanged="DataGrid1_Paging" AllowPaging="True"
> > > > PageSize="2" Width="75%" AutoGenerateColumns="False"
> > > > AlternatingItemStyle-BackColor="#dddddd" CellPadding="5" Font-Size="9pt"
> > > > Font-Name="Verdana">
> > > > <HeaderStyle backcolor="Navy" forecolor="White" font-size="13pt"
> > > > font-bold="True" horizontalalign="Center" />
> > > > <PagerStyle backcolor="Navy" forecolor="White" font-size="8pt"
> > > > font-bold="True" horizontalalign="Right" nextpagetext="Next >"
> > > > prevpagetext="< Prev" />
> > > > <Columns>
> > > > <asp:EditCommandColumn EditText="Edit" UpdateText="Update"
> > > > CancelText="Cancel" ButtonType="LinkButton" />
> > > > <asp:ButtonColumn Text="Delete" ButtonType="LinkButton"
> > > > CommandName="Delete" />
> > > >
> > > > ' FIRST COLUMN (NOT THE PROBLEM, SHOWN AS AN EXAMPLE ONLY)
> > > >
> > > > <asp:TemplateColumn HeaderText="Question" SortExpression="question">
> > > > <ItemTemplate>
> > > > <%# DataBinder.Eval(Container.DataItem, "question") %>
> > > > </ItemTemplate>
> > > > <EditItemTemplate>
> > > > <asp:TextBox runat="server" id="txtQuestion"
> > > > Columns="50" MaxLength="2000" Rows="10" Font-Name="Verdana" Font-Size="9pt"
> > > > TextMode="MultiLine" Text='<%# DataBinder.Eval(Container.DataItem,
> > > > "question") %>' />
> > > > <asp:RequiredFieldValidator runat="server"
> > > > ControlToValidate="txtQuestion" Display="Dynamic" ErrorMessage="<br />You
> > > > must provide a Question." />
> > > > </EditItemTemplate>
> > > > </asp:TemplateColumn>
> > > >
> > > > ' PROVIDE CONTRACT COLUMN INFO (THIS IS CODE THAT MAY BE IN ERR)
> > > >
> > > > <asp:TemplateColumn HeaderText="Contract"
> > > > SortExpression="contract">
> > > > <ItemTemplate>
> > > > <%# DataBinder.Eval(Container.DataItem, "contract") %>
> > > > </ItemTemplate>
> > > > <EditItemTemplate>
> > > > <asp:DropDownList runat="server" id="ddlContract"
> > > > DataSource="<%# GetContractChoice( ) %>" DataTextField="contract"
> > > > DataValueField="ID" SelectedIndex='<%#
> > > > GetContractSelectedIndex(Container.DataItem("ID")) %>' Columns="20"
> > > > MaxLength="50" Font-Name="Verdana" Font-Size="9pt" Text='<%#
> > > > DataBinder.Eval(Container.DataItem, "contract") %>' />
> > > > <asp:RequiredFieldValidator runat="server"
> > > > ControlToValidate="ddlContract" Display="Dynamic" ErrorMessage="<br />You
> > > > must provide a contract." />
> > > > </EditItemTemplate>
> > > > </asp:TemplateColumn>
> > > >
> > > > ..... ' MORE COLUMNS
> > > >
> > > > </Columns>
> > > > </asp:DataGrid>
> > > >
> > > >
> > > >[/color][/color][/color]
