在c#.net中对绑定到datatable的gridview进行排序

我有一个绑定到DataTable的gridview。当我尝试对gridview进行排序时,它变为空白。如何对这个gridview进行排序?

我知道以前有人问过这个问题,但我要找的是 解释

再说一次,我想了解实现这一点的方法,我不只是想要一个巨大的代码块。

            <asp:GridView ID="gridResults" runat="server" CellPadding="4" ForeColor="#333333"
            GridLines="Horizontal" AllowSorting="True" AllowPaging="True" 
            EmptyDataText="No Tracking Information Found for the given criteria." 
            PageSize="15" onsorted="gridResults_Sorted" AutoGenerateColumns="False" 
            EnableSortingAndPagingCallbacks="True">
            <RowStyle BackColor="#E3EAEB" />
            <FooterStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />
            <SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" />
            <HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
            <EditRowStyle BackColor="#7C6F57" />
            <AlternatingRowStyle BackColor="White" />
        </asp:GridView>

然后在代码隐藏中:

  //From search method
gridResults.Columns.Clear();
    foreach (DataColumn col in currentResults.Columns)
    {
        String fieldName = col.ColumnName;
        BoundField field = new BoundField();
        field.DataField = fieldName;
        field.SortExpression = fieldName;
        field.HeaderText = fieldName;

        gridResults.Columns.Add(field);  
    }

    gridResults.DataSource = currentResults;
    gridResults.DataBind();
    gridResults.AllowSorting = true;