protected void GridViewLog_RowDeleting(object sender, GridViewDeleteEventArgs e)
        {
            SqlDataSourceLog.DeleteCommand = "DELETE FROM WebProxyLog WHERE (ClientUserName = @clientUserName) AND (DestHost = @desthost)";
            SqlDataSourceLog.DeleteParameters.Add("clientUserName", DbType.String, e.Values[0] as string);            
            SqlDataSourceLog.DeleteParameters.Add("desthost",DbType.String, e.Values[1] as string);
            SqlDataSourceLog.Delete();

        }

            SqlDataSourceLog.DeleteCommand = "DELETE FROM WebProxyLog WHERE (ClientUserName ='"+e.Values[0] as string+"') AND (DestHost = '"+e.Values[1] as string+"')";
            SqlDataSourceLog.Delete();

            SqlDataSourceLog.DeleteCommand = "DELETE FROM WebProxyLog WHERE (ClientUserName ='"+e.Values[0] as string+"') AND (DestHost = '"+e.Values[1] as string+"')";
            SqlDataSourceLog.Delete();

SqlDataSourceLog.DeleteParameters["ClientUserName"].DefaultValue = value;

</asp:SqlDataSource>
        <asp:SqlDataSource ID="SqlDataSourceLog" runat="server" 
            ConnectionString="<%$ ConnectionStrings:isalogConnectionString %>"             
            SelectCommand="SELECT   ClientUserName, DestHost, (cast(sum(bytessent) as money)/1024/1024)  AS mb FROM WebProxyLog WHERE (DstNetwork = 'external') and ClientUserName='testuser' GROUP BY ClientUserName, DestHost ORDER BY ClientUserName, mb DESC" 

            DeleteCommand="DELETE FROM WebProxyLog WHERE (ClientUserName = @ClientUserName) AND (DestHost = @DestHost)">
            <DeleteParameters>
                <asp:Parameter Name="ClientUserName" />
                <asp:Parameter Name="DestHost" />
            </DeleteParameters>
</asp:SqlDataSource>

 protected void GridViewLog_RowDeleting(object sender, GridViewDeleteEventArgs e)
        {
           SqlDataSourceLog.DeleteParameters.Add("ClientUserName", DbType.String, e.Values[0] as string);            
           SqlDataSourceLog.DeleteParameters.Add("DestHost",DbType.String, e.Values[1] as string);
        }

    <asp:GridView ID="GridViewLog" runat="server" AllowPaging="True" 
        AllowSorting="True" AutoGenerateColumns="False" DataSourceID="SqlDataSourceLog" 
        Font-Names="Microsoft Sans Serif" Font-Size="8pt" PageSize="100" 
        style="font-family: 'Microsoft Sans Serif'" 
        onrowdeleting="GridViewLog_RowDeleting">
        <Columns>
            <asp:TemplateField ShowHeader="False">
                <ItemTemplate>
                    <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" 
                        CommandName="Delete" Text="Delete"></asp:LinkButton>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:BoundField DataField="ClientUserName" HeaderText="Login" 
                SortExpression="ClientUserName">
            <ItemStyle BackColor="#CCFFCC" ForeColor="Black" />
            </asp:BoundField>
            <asp:BoundField DataField="DestHost" HeaderText="Сайт" 
                SortExpression="DestHost" />
            <asp:BoundField DataField="mb" HeaderText="Получено МБ" ReadOnly="True" 
                SortExpression="mb" />
            <asp:BoundField DataField="clientagent" SortExpression="clientagent" />
        </Columns>
    </asp:GridView>