Problems with Optimistic Concurrency through an ObjectDataSource and a GridView

Question

Hi

I'm having a problem in an ASP .NET 2.0 Application.

I have a GridView displaying data from an ObjectDataSource (connected to a BLL class which connects to a TabledAdapter (Typed Dataset using optimistic concurrency).

The select (displaying the data) works just fine, however, when I update a row the GridView does pass the old values to the ObjectDataSource.

    <DataObjectMethod(DataObjectMethodType.Update, True)> _
    Public Function UpdateOC(ByVal original_id As Integer, ByVal original_fotonummer As Integer, ByVal original_inhoud As String, ByVal original_postdatum As Date?, ByVal fotonummer As Integer, ByVal inhoud As String, ByVal postdatum As Date?) As Boolean
        Dim tweets As TwitpicOC.TweetsDataTable = adapterOC.GetTweetById(original_id)
        If tweets.Rows.Count = 0 Then Return False
        Dim row As TwitpicOC.TweetsRow = tweets(0)

        SmijtHetErIn(row, original_fotonummer, original_inhoud, original_postdatum)
        row.AcceptChanges()

        SmijtHetErIn(row, fotonummer, inhoud, postdatum)

        Return adapterOC.Update(row) = 1
    End Function

    Public Sub SmijtHetErIn(ByVal row As TwitpicOC.TweetsRow, ByVal original_fotonummer As Integer, ByVal original_inhoud As String, ByVal original_postdatum As Date?)
        With row
            .fotonummer = original_fotonummer
            If String.IsNullOrEmpty(original_inhoud) Then .SetinhoudNull() Else .inhoud = original_inhoud
            If Not original_postdatum.HasValue Then .SetpostdatumNull() Else .postdatum = original_postdatum.Value
        End With
    End Sub

And this is the part of the page:

<div id='Overzicht' class='post'>
    <div class='title'>
        <h2>
            <a href='javascript:;'>Tweetsoverzicht</a></h2>
        <p>
            Overzicht</p>
    </div>
    <div class='entry'>
        <p>
            <asp:ObjectDataSource ID="odsGebruiker" runat="server" OldValuesParameterFormatString=""
                SelectMethod="GetAll" TypeName="TakeHomeWeb.BLL.GebruikersBLL"></asp:ObjectDataSource>
            <asp:ObjectDataSource ID="odsFoto" runat="server" SelectMethod="GetFotosByGebruiker"
                TypeName="TakeHomeWeb.BLL.FotosBLL">
                <SelectParameters>
                    <asp:ControlParameter ControlID="ddlGebruiker" DefaultValue="0" Name="userid" PropertyName="SelectedValue"
                        Type="Int32" />
                </SelectParameters>
            </asp:ObjectDataSource>
            <form id="form1" runat="server">
            <asp:Label runat="server" AssociatedControlID="ddlGebruiker">Gebruiker:&nbsp;</asp:Label>
            <asp:DropDownList ID="ddlGebruiker" runat="server" AutoPostBack="True" DataSourceID="odsGebruiker"
                DataTextField="naam" DataValueField="userid" AppendDataBoundItems="True">
                <asp:ListItem Text="Kies een gebruiker" Value="-1" />
            </asp:DropDownList>
            <br />
            <asp:Label runat="server" AssociatedControlID="ddlFoto">Foto:&nbsp;</asp:Label>
            <asp:DropDownList ID="ddlFoto" runat="server" AutoPostBack="True" DataSourceID="odsFoto"
                DataTextField="url" DataValueField="id" AppendDataBoundItems="True">
                <asp:ListItem Value="-1">Kies een foto...</asp:ListItem>
            </asp:DropDownList>
            <br />
            <div style="float: left">
                <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="id"
                    DataSourceID="odsTweets">
                    <Columns>
                        <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" />
                        <asp:BoundField DataField="id" HeaderText="id" InsertVisible="False" ReadOnly="True"
                            SortExpression="id" />
                        <asp:BoundField DataField="fotonummer" HeaderText="fotonummer" SortExpression="fotonummer" />
                        <asp:BoundField DataField="inhoud" HeaderText="inhoud" SortExpression="inhoud" />
                        <asp:BoundField DataField="postdatum" HeaderText="postdatum" SortExpression="postdatum" />
                    </Columns>
                </asp:GridView>
                <asp:ObjectDataSource ID="odsTweets" runat="server" ConflictDetection="CompareAllValues"
                    DeleteMethod="DeleteOC" OldValuesParameterFormatString="original_{0}" SelectMethod="GetTweetsByFotoId"
                    TypeName="TakeHomeWeb.BLL.TweetsOCBLL" UpdateMethod="UpdateOC">
                    <DeleteParameters>
                        <asp:Parameter Name="original_id" Type="Int32" />
                        <asp:Parameter Name="original_fotonummer" Type="Int32" />
                        <asp:Parameter Name="original_inhoud" Type="String" />
                        <asp:Parameter Name="original_postdatum" Type="DateTime" />
                    </DeleteParameters>
                    <UpdateParameters>
                        <asp:Parameter Name="original_id" Type="Int32" />
                        <asp:Parameter Name="original_fotonummer" Type="Int32" />
                        <asp:Parameter Name="original_inhoud" Type="String" />
                        <asp:Parameter Name="original_postdatum" Type="DateTime" />
                        <asp:Parameter Name="fotonummer" Type="Int32" />
                        <asp:Parameter Name="inhoud" Type="String" />
                        <asp:Parameter Name="postdatum" Type="DateTime" />
                    </UpdateParameters>
                    <SelectParameters>
                        <asp:ControlParameter ControlID="ddlFoto" Name="foto" PropertyName="SelectedValue"
                            Type="Int32" />
                    </SelectParameters>
                </asp:ObjectDataSource>
            </div>
            </form>
        </p>
    </div>
</div>

I've got a feeling there's huge fail involved or something, but I've been staring at it for hours now and I just can't find it.

Answer 1

Hi,

I had the exact same problem. I was trying to get optimistic concurrency to work so i started from a deletion on a table with 2 columns

but according to the local window, it seemed like the dataGrid is passing null
for values other than the primary key.

anyways after tweaking and reading here and there, this was the solution to my problems:

on ObjectDataSource i modified 1 property: ConflictDetection="CompareAllValues"

silly me..