ASP.NET GridView默认排序顺序

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnSorting="GridView1_Sorting">
   <Columns>
        <asp:BoundField DataField="ID" HeaderText="ID" SortExpression="ID" />
        <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
        <asp:BoundField DataField="Age" HeaderText="Age" SortExpression="Age" />
    </Columns>
</asp:GridView>

protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
{
    // 获取当前排序列
    string sortExpression = e.SortExpression;

    // 获取当前排序方向
    string sortDirection = e.SortDirection;

    // 如果当前排序方向为升序，则更改为降序
    if (sortDirection == "Ascending")
    {
        e.SortDirection = "Descending";
    }
    else
    {
        e.SortDirection = "Ascending";
    }

    // 绑定数据
    BindData();

    // 设置排序列和排序方向
    GridView1.DataSource = GetData(sortExpression, e.SortDirection);
    GridView1.DataBind();
}