SqlDataSource里的几个属性不懂,哪位讲解下!

Question

<asp:SqlDataSource id="alltoipcSqlDataSource" runat="server" SelectCommand="SELECT [topicid], [topictitle], [views], [comments], [update_date] FROM [topics] WHERE ([comments] >= @comments) ORDER BY [update_date] DESC" ConnectionString="<%$ ConnectionStrings:dbconnection %>"><SelectParameters>
<asp:ControlParameter PropertyName="Value" Type="Int32" DefaultValue="0" Name="comments" ControlID="topickindHiddenField"></asp:ControlParameter>
</SelectParameters>
</asp:SqlDataSource>
哪位可以讲解下这里面的如下几个属性有什么用途啊?
PropertyName="Value" Type="Int32" DefaultValue="0" Name="comments" ControlID="topickindHiddenField"