Hi
On page 267 when I try to update a record in the DetailsView control I get this error message

"The data types text and nvarchar are incompatible in the equal to operator.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: The data types text and nvarchar are incompatible in the equal to operator."

Any advice on why this isn't working and how I fix it?

Many thanks
Judy

Hi Judy,

Can you post the relevant pieces of code for this?

You get this error when your database contains a Text column, and your code thinks it's an nvarchar column, or vice versa. Only by looking at the relevant code and database schema can we provide useful suggestions.

Imar
---------------------------------------
Imar Spaanjaars
http://Imar.Spaanjaars.Com
Everyone is unique, except for me.
Author of ASP.NET 2.0 Instant Results and Beginning Dreamweaver MX / MX 2004
Want to be my colleague? Then check out this post.

Here is my page:

<%@ Page Language="C#" MasterPageFile="~/site.master" AutoEventWireup="true" CodeFile="Fixtures.aspx.cs" Inherits="Fixtures" Title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="mainContent" Runat="Server">
    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="FixtureID"
        DataSourceID="SqlDataSource1" EmptyDataText="There are no data records to display.">
        <Columns>
            <asp:CommandField ShowSelectButton="True" ShowEditButton="True" ShowDeleteButton="True" />
            <asp:BoundField DataField="FixtureID" HeaderText="FixtureID" ReadOnly="True" SortExpression="FixtureID" />
            <asp:BoundField DataField="FixtureDate" HeaderText="FixtureDate" SortExpression="FixtureDate" />
            <asp:BoundField DataField="FixtureType" HeaderText="FixtureType" SortExpression="FixtureType" />
            <asp:BoundField DataField="GoalsFor" HeaderText="GoalsFor" SortExpression="GoalsFor" />
            <asp:BoundField DataField="GoalsAgainst" HeaderText="GoalsAgainst" SortExpression="GoalsAgainst" />
            <asp:BoundField DataField="Notes" HeaderText="Notes" SortExpression="Notes" />
            <asp:BoundField DataField="Opponents" HeaderText="Opponents" SortExpression="Opponents" />
        </Columns>
    </asp:GridView>
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:WroxUnitedConnectionString %>"
        ProviderName="<%$ ConnectionStrings:WroxUnitedConnectionString1.Prov iderName %>"
        SelectCommand="SELECT [FixtureType], [FixtureID], [FixtureDate], [GoalsFor], [GoalsAgainst], [Notes], [Opponents] FROM [Fixtures]" DeleteCommand="DELETE FROM [Fixtures] WHERE [FixtureID] = @FixtureID" InsertCommand="INSERT INTO [Fixtures] ([FixtureType], [FixtureDate], [GoalsFor], [GoalsAgainst], [Notes], [Opponents]) VALUES (@FixtureType, @FixtureDate, @GoalsFor, @GoalsAgainst, @Notes, @Opponents)" UpdateCommand="UPDATE [Fixtures] SET [FixtureType] = @FixtureType, [FixtureDate] = @FixtureDate, [GoalsFor] = @GoalsFor, [GoalsAgainst] = @GoalsAgainst, [Notes] = @Notes, [Opponents] = @Opponents WHERE [FixtureID] = @FixtureID">
        <DeleteParameters>
            <asp:Parameter Name="FixtureID" Type="Int32" />
        </DeleteParameters>
        <UpdateParameters>
            <asp:Parameter Name="FixtureType" Type="String" />
            <asp:Parameter Name="FixtureDate" Type="DateTime" />
            <asp:Parameter Name="GoalsFor" Type="Int16" />
            <asp:Parameter Name="GoalsAgainst" Type="Int16" />
            <asp:Parameter Name="Notes" Type="String" />
            <asp:Parameter Name="Opponents" Type="String" />
            <asp:Parameter Name="FixtureID" Type="Int32" />
        </UpdateParameters>
        <InsertParameters>
            <asp:Parameter Name="FixtureType" Type="String" />
            <asp:Parameter Name="FixtureDate" Type="DateTime" />
            <asp:Parameter Name="GoalsFor" Type="Int16" />
            <asp:Parameter Name="GoalsAgainst" Type="Int16" />
            <asp:Parameter Name="Notes" Type="String" />
            <asp:Parameter Name="Opponents" Type="String" />
        </InsertParameters>
    </asp:SqlDataSource>
    <asp:DetailsView ID="DetailsView1" runat="server" AutoGenerateRows="False" DataKeyNames="FixtureID"
        DataSourceID="SqlDataSource2" Height="50px" Width="450px" DefaultMode="Insert">
        <Fields>
            <asp:BoundField DataField="FixtureID" HeaderText="FixtureID" InsertVisible="False"
                ReadOnly="True" SortExpression="FixtureID" />
            <asp:BoundField DataField="FixtureDate" HeaderText="FixtureDate" SortExpression="FixtureDate" />
            <asp:BoundField DataField="FixtureType" HeaderText="FixtureType" SortExpression="FixtureType" />
            <asp:BoundField DataField="GoalsFor" HeaderText="GoalsFor" SortExpression="GoalsFor" />
            <asp:BoundField DataField="GoalsAgainst" HeaderText="GoalsAgainst" SortExpression="GoalsAgainst" />
            <asp:BoundField DataField="Notes" HeaderText="Notes" SortExpression="Notes" />
            <asp:BoundField DataField="Opponents" HeaderText="Opponents" SortExpression="Opponents" />
            <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" ShowInsertButton="True" />
        </Fields>
    </asp:DetailsView>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:WroxUnited %>"
        SelectCommand="SELECT [FixtureID], [FixtureDate], [FixtureType], [GoalsFor], [GoalsAgainst], [Notes], [Opponents] FROM [Fixtures]"
        ConflictDetection="CompareAllValues"
        DeleteCommand="DELETE FROM [Fixtures] WHERE [FixtureID] = @original_FixtureID AND [FixtureDate] = @original_FixtureDate AND [FixtureType] = @original_FixtureType AND [GoalsFor] = @original_GoalsFor AND [GoalsAgainst] = @original_GoalsAgainst AND [Notes] = @original_Notes AND [Opponents] = @original_Opponents"


        InsertCommand="INSERT INTO [Fixtures] ([FixtureDate], [FixtureType], [GoalsFor], [GoalsAgainst], [Notes], [Opponents]) VALUES (@FixtureDate, @FixtureType, @GoalsFor, @GoalsAgainst, @Notes, @Opponents)"
        OldValuesParameterFormatString="original_{0}"
        UpdateCommand="UPDATE [Fixtures] SET [FixtureDate] = @FixtureDate, [FixtureType] = @FixtureType, [GoalsFor] = @GoalsFor, [GoalsAgainst] = @GoalsAgainst, [Notes] = @Notes, [Opponents] = @Opponents WHERE [FixtureID] = @original_FixtureID AND [FixtureDate] = @original_FixtureDate AND [FixtureType] = @original_FixtureType AND [GoalsFor] = @original_GoalsFor AND [GoalsAgainst] = @original_GoalsAgainst AND [Notes] = @original_Notes AND [Opponents] = @original_Opponents">
        <DeleteParameters>
            <asp:Parameter Name="original_FixtureID" Type="Int32" />
            <asp:Parameter Name="original_FixtureDate" Type="DateTime" />
            <asp:Parameter Name="original_FixtureType" Type="String" />
            <asp:Parameter Name="original_GoalsFor" Type="Int16" />
            <asp:Parameter Name="original_GoalsAgainst" Type="Int16" />
            <asp:Parameter Name="original_Notes" Type="String" />
            <asp:Parameter Name="original_Opponents" Type="String" />
        </DeleteParameters>
        <UpdateParameters>
            <asp:Parameter Name="FixtureDate" Type="DateTime" />
            <asp:Parameter Name="FixtureType" Type="String" />
            <asp:Parameter Name="GoalsFor" Type="Int16" />
            <asp:Parameter Name="GoalsAgainst" Type="Int16" />
            <asp:Parameter Name="Notes" Type="String" />
            <asp:Parameter Name="Opponents" Type="String" />
            <asp:Parameter Name="original_FixtureID" Type="Int32" />
            <asp:Parameter Name="original_FixtureDate" Type="DateTime" />
            <asp:Parameter Name="original_FixtureType" Type="String" />
            <asp:Parameter Name="original_GoalsFor" Type="Int16" />
            <asp:Parameter Name="original_GoalsAgainst" Type="Int16" />
            <asp:Parameter Name="original_Notes" Type="String" />
            <asp:Parameter Name="original_Opponents" Type="String" />
        </UpdateParameters>
        <InsertParameters>
            <asp:Parameter Name="FixtureDate" Type="DateTime" />
            <asp:Parameter Name="FixtureType" Type="String" />
            <asp:Parameter Name="GoalsFor" Type="Int16" />
            <asp:Parameter Name="GoalsAgainst" Type="Int16" />
            <asp:Parameter Name="Notes" Type="String" />
            <asp:Parameter Name="Opponents" Type="String" />
        </InsertParameters>
    </asp:SqlDataSource>
</asp:Content>

In what tables (and for what columns) are you using the text data type? Does the book instruct you to use those types? (That is, is the table correct and does it line up with the code you need to write?)

Imar
---------------------------------------
Imar Spaanjaars
http://Imar.Spaanjaars.Com
Everyone is unique, except for me.
Author of ASP.NET 2.0 Instant Results and Beginning Dreamweaver MX / MX 2004
Want to be my colleague? Then check out this post.