根据DataGrid绑定的列的SortException字段进行排序

为DataGrid的某字段进行排序
        protected void dg_UserInfo_SortCommand(object source, System.Web.UI.WebControls.DataGridSortCommandEventArgs e)
        {
            labWrong.Text = "";

            if (ViewState["SortExpression"] != null)
            {
                if (ViewState["SortExpression"].ToString() == e.SortExpression.ToString())
                {
                    string cSortExpression = "";
                    if (ViewState["SortExpression"].ToString().Length > 5)
                    {
                        cSortExpression = ViewState["SortExpression"].ToString().Substring(ViewState["SortExpression"].ToString().Length - 5 - 1 , 5);
                    }
                    if (cSortExpression == " DESC")
                    {
                        ViewState["SortExpression"] = e.SortExpression;
                    }
                    else
                    {
                        ViewState["SortExpression"] = e.SortExpression + " DESC";
                    }
                }
                else
                {
                    ViewState["SortExpression"] = e.SortExpression;
                }
            }
            else
            {
                ViewState["SortExpression"] = e.SortExpression;
            }

//绑定列表的选择项为未选择    
    dg_UserInfo.SelectedIndex = -1;
//绑定列表数据
            BindData_dg_UserInfo();
        }

绑定函数中的对应代码
//取出指定表的所有记录。
            DataTable dtUserInfo = UserManage.GetAllUsers();
            // sort the view according to the value stored in the ViewState, in any
            DataView dvUserInfo = dtUserInfo.DefaultView;
            if (ViewState["SortExpression"] != null)
                dvUserInfo.Sort = ViewState["SortExpression"].ToString();
            dg_UserInfo.DataSource = dvUserInfo;
            dg_UserInfo.DataBind();