GridView中的双向排序

1. 设置GridView 的属性　AllowSorting="True"　否则没有可排序的下横线.
2. 邦定要序排的字段

<asp:BoundField HeaderText="货号" DataField="ch_MaterialID" SortExpression="ch_MaterialID">
                                <ItemStyle Height="10px" Width="100px" />
                            </asp:BoundField>

3. 写排序的事件代码:

        //在排序发生前激发
        protected void GVStorageMaterial_Sorting(object sender, GridViewSortEventArgs e)
        {
            string strPage = e.SortExpression.ToString();
            switch (strPage)
            {
                case "ch_ImageID":
                    ViewState["SortOrder"] = "ch_ImageID";
                    break;
                case "ch_MaterialID":
                    ViewState["SortOrder"] = "ch_MaterialID";
                    break;
                case "ch_MaterialName":
                    ViewState["SortOrder"] = "ch_MaterialName";
                    break;
            }
            
            //string sPage = e.SortExpression;
            if (ViewState["OrderDire"] == null)
            {
                ViewState["OrderDire"] = "ASC";
            }
            if (ViewState["OrderDire"].ToString() == "ASC")
                ViewState["OrderDire"] = "DESC";
            else
                ViewState["OrderDire"] = "ASC";
            string strSQLSel = StrSqlSearch();
            this.InitializeGridview(strSQLSel);
        }

4. 在显示GridView的视图中设置排序的属性.
string sort = (string)ViewState["SortOrder"] + " " + (string)ViewState["OrderDire"];

bool flagSel = objDBAccess.SearchSQL(strSQLSel, out objDS, out strMessage);
            if (flagSel)
            {
                DataView dv=objDS.Tables[0].DefaultView;
                dv.Sort = strSort;
                GV.DataSource = dv;
                GV.DataBind();
            }