Telerik RadDataPager，如何在pager中添加pagesize字段

<telerik:RadDataPager ID="RadDataPager1" runat="server" PageSize="10" PageSizeDropDownType="None">
</telerik:RadDataPager>

<telerik:RadDataPager ID="RadDataPager1" runat="server" PageSize="10" PageSizeDropDownType="None" DataSourceID="GridView1">
</telerik:RadDataPager>

<asp:GridView ID="GridView1" runat="server" DataSourceID="SqlDataSource1">
</asp:GridView>

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>"
    SelectCommand="SELECT * FROM [TableName]">
</asp:SqlDataSource>

protected void RadDataPager1_PageIndexChanged(object sender, Telerik.Web.UI.RadDataPagerPageIndexChangeEventArgs e)
{
    // 获取当前页码和页面大小
    int currentPageIndex = e.NewPageIndex;
    int pageSize = RadDataPager1.PageSize;

    // 根据页码和页面大小查询数据
    // ...

    // 更新数据源控件
    // ...
}