Problemer med detailsview

Hej,

Har problemer med at få vist mit indhold i detailsview! Den viser intet. Hvad er problemet? 


<asp:DetailsView ID="DetailsView1" runat="server" EnableViewState="False" AutoGenerateRows="False" DataKeyNames="MailId"
        DataSourceID="SqlDataSource1">
        <Fields>
            <asp:BoundField DataField="MailId" HeaderText="MailId" InsertVisible="False" ReadOnly="True" SortExpression="MailId" />
            <asp:BoundField DataField="UserId" HeaderText="UserId" SortExpression="UserId" />
            <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
            <asp:BoundField DataField="Email" HeaderText="Email" SortExpression="Email" />
            <asp:BoundField DataField="Subject" HeaderText="Subject" SortExpression="Subject" />
            <asp:BoundField DataField="Message" HeaderText="Message" SortExpression="Message" />
            <asp:BoundField DataField="Date" HeaderText="Date" SortExpression="Date" />
        </Fields>
    </asp:DetailsView>
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:AimsterDBConnectionString %>"
        SelectCommand="SELECT [MailId], [UserId], [Name], [Email], [Subject], [Message], [Date] FROM [Mail] WHERE ([MailId] = @MailId)">
        <SelectParameters>
            <asp:QueryStringParameter Name="MailId" QueryStringField="MailId" />
        </SelectParameters>
    </asp:SqlDataSource>


Tak!