SqlDataSource参数化查询所有记录

 <div>        <asp:DropDownList ID="ddlTypeid" runat="server" AutoPostBack="true">           <asp:ListItem Value="">所有</asp:ListItem>           <asp:ListItem Value="1">1</asp:ListItem>           <asp:ListItem Value="2">2</asp:ListItem>           <asp:ListItem Value="3">3</asp:ListItem>           <asp:ListItem Value="4">4</asp:ListItem>        </asp:DropDownList>    </div>    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"        DataSourceID="SqlDataSource1">        <Columns>            <asp:BoundField DataField="ID" HeaderText="ID" SortExpression="ID" />            <asp:BoundField DataField="TypeID" HeaderText="TypeID"                SortExpression="TypeID" />            <asp:BoundField DataField="Title" HeaderText="Title" SortExpression="Title" />            <asp:BoundField DataField="AddDate" HeaderText="AddDate"                SortExpression="AddDate" />        </Columns>    </asp:GridView>    <asp:SqlDataSource ID="SqlDataSource1" runat="server"        ConnectionString="Data Source=LICHUAN-64EDE70;Initial Catalog=Tests;Integrated Security=True"        ProviderName="System.Data.SqlClient" SelectCommand="SELECT * FROM [Article] where typeid=@typeid or @typeid = -1">           <selectparameters>              <asp:controlparameter name="typeid" ControlID ="ddlTypeid" propertyname="SelectedValue" DefaultValue="-1"/>          </selectparameters>    </asp:SqlDataSource>