GridView控件不能格式化！不知道是否是个Bug!

今天发现GridView控件绑定列里用了DataFormatString,竟然没有效果出来。但DataGrid的就可以.

 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Exid" DataSourceID="SqlDataSource1">
            <Columns>
                               
                <asp:BoundField DataField="Eatexes" HeaderText="GridView-price"  DataFormatString="{0:F2}"/>
              
            </Columns>
        </asp:GridView>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="Data Source=WEBSERVER;Initial Catalog=demo;User ID=sa;Password=123"
            ProviderName="System.Data.SqlClient" SelectCommand="SELECT * FROM [CL_expenses]">
        </asp:SqlDataSource>
        
        <asp:DataGrid ID="dd" runat="server" AutoGenerateColumns="False" DataSourceID="SqlDataSource1">
            <Columns>
                <asp:BoundColumn DataField="Eatexes" DataFormatString="{0:F2}" HeaderText="DataGrid-price"></asp:BoundColumn>
            </Columns>
        </asp:DataGrid>