GridView表头排序方法设置

<asp:GridView ID="gvData" runat="server" AutoGenerateColumns="False"
                    OnRowDataBound="gvData_RowDataBound"
                    onsorting="gvData_Sorting" AllowSorting="true">
                    <Columns>
                        <asp:TemplateField HeaderText="新闻标题">
                            <ItemTemplate>
                                <asp:Label ID="labtitle" runat="server" Text=‘<%# Bind("title") %>‘></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="阅读量" SortExpression="count">
                            <ItemTemplate>
                                <asp:Label ID="labcount" runat="server" Text=‘<%# Bind("count") %>‘></asp:Label>
                            </ItemTemplate>
                            <ItemStyle Width="15%" />
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="添加人">
                            <ItemTemplate>
                                <asp:Label ID="labadmin" runat="server" Text=‘<%# Bind("adminName") %>‘></asp:Label>
                            </ItemTemplate>
                            <ItemStyle Width="25%" />
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="时间" SortExpression="ID">
                            <ItemTemplate>
                                添加：<asp:Label ID="labtime" runat="server" Text=‘<%# Bind("times") %>‘></asp:Label>
                                <asp:Label ID="labtimepass" runat="server" Text=‘<%# Bind("timepass") %>‘></asp:Label>
                                <br />
                            </ItemTemplate>
                            <ItemStyle Width="30%" />
                        </asp:TemplateField>
                    </Columns>
                </asp:GridView>

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            ViewState["SortOrder"] = "ID";　　//默认排序字段，必须
            ViewState["OrderDire"] = "Desc";  //默认排序，必须
            fillData();
        }
    }
    protected void fillData()
    {
　　　　string sort = (string)ViewState["SortOrder"] + " " + (string)ViewState["OrderDire"];

　　　　string sql = “select * from dt_news ”+sort;
　　　　
　　　　//datatable 自己写，绑定GridView自己写，我这里就不写了

　　}

protected void gvData_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        //判断是否是表头
        if (e.Row.RowType == DataControlRowType.Header)
        {
            //判断是否进行排序
            //是否是排序字段信息
            for (int i = 0; i < e.Row.Cells.Count; i++)
            {
                ControlCollection  cons= e.Row.Cells[i].Controls;
                if (cons.Count == 1)
                {
                    LinkButton lb = cons[0] as LinkButton;
                    if (lb != null)
                    {
                        if (ViewState["SortOrder"].ToString() == lb.CommandArgument)
                        {
                            if (ViewState["OrderDire"].ToString() == "Desc")
                            {
                                lb.Text += "▼";
                            }
                            else
                            {
                                lb.Text += "▲";
                            }
                        }
                    }
                }
            }
        }
    }

protected void gvData_Sorting(object sender, GridViewSortEventArgs e)
    {
        string sPage = e.SortExpression;

        if (ViewState["SortOrder"].ToString() == sPage)
        {
            if (ViewState["OrderDire"].ToString() == "Desc")

                ViewState["OrderDire"] = "ASC";
            else
                ViewState["OrderDire"] = "Desc";
        }
        else
        {
            ViewState["SortOrder"] = e.SortExpression;
        }
        PageControl1.pageNow = 1;
        fillData();
    }