出现Operator '==' incompatible with operand types 'Int32' and 'Object'

Question

<asp:GridView ID="GridView5" runat="server" AutoGenerateColumns="False" 
            DataKeyNames="CategoryId" DataSourceID="LinqDataSource1"  >
            <Columns>
                <asp:CommandField ShowSelectButton="True" />
                <asp:BoundField DataField="CategoryId" HeaderText="CategoryId" 
                    InsertVisible="False" ReadOnly="True" SortExpression="CategoryId" />
                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                <asp:BoundField DataField="Descn" HeaderText="Descn" SortExpression="Descn" />
            </Columns>
        </asp:GridView>
        <asp:LinqDataSource ID="LinqDataSource1" runat="server" 
            ContextTypeName="DatabaeseDataContext" EntityTypeName="" TableName="Categories">
        </asp:LinqDataSource>
        <asp:DetailsView ID="DetailsView2" runat="server" AutoGenerateRows="False" 
            DataKeyNames="CategoryId" DataSourceID="LinqDataSource8" Height="50px" 
            Width="202px">
            <Fields>
                <asp:BoundField DataField="CategoryId" HeaderText="CategoryId" 
                    InsertVisible="False" ReadOnly="True" SortExpression="CategoryId" />
                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                <asp:BoundField DataField="Descn" HeaderText="Descn" SortExpression="Descn" />
                <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" 
                    ShowInsertButton="True" />
            </Fields>
        </asp:DetailsView>
                <asp:LinqDataSource ID="LinqDataSource8" runat="server" 
            ContextTypeName="DatabaeseDataContext" EnableDelete="True" EnableInsert="True" 
            EnableUpdate="True" EntityTypeName="" TableName="Categories" 
            Where="CategoryId ==@CategoryId"  >    -------就是这里出现错误
            <WhereParameters>
                <asp:ControlParameter ControlID="GridView5" Name="CategoryId" 
                    PropertyName="SelectedValue" Type="Int32" />
            </WhereParameters>
        </asp:LinqDataSource>
求解答。。谢谢

Answer 1

@CategoryId啥东西，解析不了，谁知到它代表什么int值

Answer 2

Where="CategoryId ==@CategoryId只看见了两个“==”，可以这样写吗？重载运算符的操作c#还是基本没有的（还没见）,linq 会报这个错误，挺有意思的。

Answer 3

倒数第三行不是 有PropertyName="SelectedValue" Type="Int32" />么
怎么还会报错啊？