Empty Dictionary Error on Delete with SqlDataSource - ASP.net ListView

Question

I'm trying to make a simple ListView with optimistic concurrency. It uses the VS-automatically-generated Delete, Insert, Update statements (except 1 change to insert: see code). Insert and Edit work fine and commit to the database. When trying to delete, I get this error:

You have specified that your delete command compares all values on SqlDataSource 'MySourceHere', but the dictionary passed in for values is empty. Pass in a valid dictionary for delete or change your mode to OverwriteChanges.

I've tried just changing "CompareAllValues" to "OverwriteChanges" to postpone concurrency work for later, but that "breaks" Update and Delete commands, which just seem to refresh the ListView with the old values. The only threads I could find that resolved this issue involved changing to "OverwriteChanges" or were people who didn't have a "DataKeyNames" declared. Relevent markup is below (I hope).

Any thoughts?

<asp:SqlDataSource ID="ManageUsersSource" runat="server" 
    ConflictDetection="CompareAllValues" 
    ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
        DeleteCommand="DELETE FROM [DUSER] WHERE [userid] = ? AND (([username] = ?) OR ([username] IS NULL AND ? IS NULL)) AND (([userpass] = ?) OR ([userpass] IS NULL AND ? IS NULL))" 
    InsertCommand="INSERT INTO [DUSER] ([username], [userpass]) VALUES (?, ?)" 
    OldValuesParameterFormatString="original_{0}" 
    ProviderName="<%$ ConnectionStrings:ConnectionString.ProviderName %>" 
    SelectCommand="SELECT * FROM [DUSER] ORDER BY [userid] ASC" 
    UpdateCommand="UPDATE [DUSER] SET [username] = ?, [userpass] = ? WHERE [userid] = ? AND (([username] = ?) OR ([username] IS NULL AND ? IS NULL)) AND (([userpass] = ?) OR ([userpass] IS NULL AND ? IS NULL))">
    <DeleteParameters>
        <asp:Parameter Name="original_userid" Type="Int16" />
        <asp:Parameter Name="original_username" Type="String" />
        <asp:Parameter Name="original_username" Type="String" />
        <asp:Parameter Name="original_userpass" Type="String" />
        <asp:Parameter Name="original_userpass" Type="String" />
    </DeleteParameters>
    <InsertParameters>
    <%--This is removed since [userid] is an automatically generated index.--%>
        <%--<asp:Parameter Name="userid" Type="Int16" />--%>
        <asp:Parameter Name="username" Type="String" />
        <asp:Parameter Name="userpass" Type="String" />
    </InsertParameters>
    <UpdateParameters>
        <asp:Parameter Name="username" Type="String" />
        <asp:Parameter Name="userpass" Type="String" />
        <asp:Parameter Name="original_userid" Type="Int16" />
        <asp:Parameter Name="original_username" Type="String" />
        <asp:Parameter Name="original_username" Type="String" />
        <asp:Parameter Name="original_userpass" Type="String" />
        <asp:Parameter Name="original_userpass" Type="String" />
    </UpdateParameters>
</asp:SqlDataSource>
<asp:ListView ID="ListView1" runat="server" DataKeyNames="userid" 
    DataSourceID="ManageUsersSource" InsertItemPosition="LastItem">
    <AlternatingItemTemplate>
        <tr style="background-color:#FFF8DC;">
            <td>
                <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" 
                    Text="Delete" />
                <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
                <asp:Label ID="useridLabel" runat="server" Text='<%# Eval("userid") %>' />
            </td>
            <td>
                <asp:Label ID="usernameLabel" runat="server" Text='<%# Eval("username") %>' />
            </td>
            <td>
                <asp:Label ID="userpassLabel" runat="server" Text='<%# Eval("userpass") %>' />
            </td>
        </tr>
    </AlternatingItemTemplate>
    <EditItemTemplate>
        <tr style="background-color:#008A8C;color: #FFFFFF;">
            <td>
                <asp:Button ID="UpdateButton" runat="server" CommandName="Update" 
                    Text="Update" />
                <asp:Button ID="CancelButton" runat="server" CommandName="Cancel" 
                    Text="Cancel" />
            </td>
            <td>
                <asp:Label ID="useridLabel1" runat="server" Text='<%# Eval("userid") %>' />
            </td>
            <td>
                <asp:TextBox ID="usernameTextBox" runat="server" 
                    Text='<%# Bind("username") %>' />
            </td>
            <td>
                <asp:TextBox ID="userpassTextBox" runat="server" 
                    Text='<%# Bind("userpass") %>' />
            </td>
        </tr>
    </EditItemTemplate>
    <EmptyDataTemplate>
        <table runat="server" 
            style="background-color: #FFFFFF;border-collapse: collapse;border-color: #999999;border-style:none;border-width:1px;">
            <tr>
                <td>
                    No data was returned.</td>
            </tr>
        </table>
    </EmptyDataTemplate>
    <InsertItemTemplate>
        <tr style="">
            <td>
                <asp:Button ID="InsertButton" runat="server" CommandName="Insert" 
                    Text="Insert" />
                <asp:Button ID="CancelButton" runat="server" CommandName="Cancel" 
                    Text="Clear" />
            </td>
            <td>
                &nbsp;</td>
            <td>
                <asp:TextBox ID="usernameTextBox" runat="server" 
                    Text='<%# Bind("username") %>' />
            </td>
            <td>
                <asp:TextBox ID="userpassTextBox" runat="server" 
                    Text='<%# Bind("userpass") %>' />
            </td>
        </tr>
    </InsertItemTemplate>
    <ItemTemplate>
        <tr style="background-color:#DCDCDC;color: #000000;">
            <td>
                <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" 
                    Text="Delete" />
                <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
                <asp:Label ID="useridLabel" runat="server" Text='<%# Eval("userid") %>' />
            </td>
            <td>
                <asp:Label ID="usernameLabel" runat="server" Text='<%# Eval("username") %>' />
            </td>
            <td>
                <asp:Label ID="userpassLabel" runat="server" Text='<%# Eval("userpass") %>' />
            </td>
        </tr>
    </ItemTemplate>
    <LayoutTemplate>
        <table runat="server">
            <tr runat="server">
                <td runat="server">
                    <table ID="itemPlaceholderContainer" runat="server" border="1" 
                        style="background-color: #FFFFFF;border-collapse: collapse;border-color: #999999;border-style:none;border-width:1px;font-family: Verdana, Arial, Helvetica, sans-serif;">
                        <tr runat="server" style="background-color:#DCDCDC;color: #000000;">
                            <th runat="server">
                            </th>
                            <th runat="server">
                                userid</th>
                            <th runat="server">
                                username</th>
                            <th runat="server">
                                userpass</th>
                        </tr>
                        <tr ID="itemPlaceholder" runat="server">
                        </tr>
                    </table>
                </td>
            </tr>
            <tr runat="server">
                <td runat="server" 
                    style="text-align: center;background-color: #CCCCCC;font-family: Verdana, Arial, Helvetica, sans-serif;color: #000000;">
                    <asp:DataPager ID="DataPager1" runat="server">
                        <Fields>
                            <asp:NextPreviousPagerField ButtonType="Button" ShowFirstPageButton="True" 
                                ShowLastPageButton="True" />
                        </Fields>
                    </asp:DataPager>
                </td>
            </tr>
        </table>
    </LayoutTemplate>
    <SelectedItemTemplate>
        <tr style="background-color:#008A8C;font-weight: bold;color: #FFFFFF;">
            <td>
                <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" 
                    Text="Delete" />
                <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
                <asp:Label ID="useridLabel" runat="server" Text='<%# Eval("userid") %>' />
            </td>
            <td>
                <asp:Label ID="usernameLabel" runat="server" Text='<%# Eval("username") %>' />
            </td>
            <td>
                <asp:Label ID="userpassLabel" runat="server" Text='<%# Eval("userpass") %>' />
            </td>
        </tr>
    </SelectedItemTemplate>
</asp:ListView>

Answer 1

Changing the non-Primary Key fields to use "Bind" instead of "Eval" in my ItemTemplate/AlternatingItemTemplate (just like an Edit Template) was apparently needed to properly pass along the old values.

This was a case of using automatically generated markup without fully understanding it (I still don't, really.)

Answer 2

You could try simplifying your Update and Delete Commands. Since userid (your DataKeyName) is automatically generated and, therefore, unique, you do not need the extra parameters.

So, your UpdateCommand would be

"UPDATE [DUSER] SET [username] = ?, [userpass] = ? WHERE [userid] = ?"

with the following parameters:-

<UpdateParameters>
    <asp:Parameter Name="userid" Type="Int16" />
    <asp:Parameter Name="username" Type="String" />
    <asp:Parameter Name="userpass" Type="String" />
</UpdateParameters>

Your DeleteCommand would be

"DELETE FROM [DUSER] WHERE [userid] = ?"

with the following parameters:-

<DeleteParameters>
    <asp:Parameter Name="userid" Type="Int16" />
</DeleteParameters>

Answer 3

Sorry, I forgot to change the ?s and that you want optimistic concurrency.

"UPDATE [DUSER] SET [username] = @username, [userpass] = @userpass WHERE [userid] = @userid And [username] = @original_username And [userpass] = @original_userpass"

"DELETE FROM [DUSER] WHERE [userid] = @userid And [username] = @original_username And [userpass] = @original_userpass"

You will, of course, need to check to see if the row was updated/deleted.

Your InserCommand should also be:-

"INSERT INTO [DUSER] ([username], [userpass]) VALUES (@username, @userpass)"

Assuming username and userpass are set to not allow nulls, which they should be in this case, then the Commands will fail if either parameter is null.

To avoid this, add an <asp:RequiredFieldValidator> to each of the usernameTextBox and userpassTextBox controls to provide client-side validation.

You should also change the IDs of the TextBox controls to match the parameter names.

If you WERE having to deal with null values then you would need the other parts of the generated queries where null comparison is begin used, replacing the ?s with the appropriate parameter.