Gridview中排序方法二

前台代码：

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
            <Columns>
                <asp:BoundField DataField="CustomerID" HeaderText="CustomerID" />
                <asp:BoundField DataField="CompanyName" HeaderText="CompanyName" />
                <asp:BoundField DataField="ContactName" HeaderText="ContactName" />
                <asp:BoundField DataField="ContactTitle" HeaderText="ContactTitle" />
            </Columns>
        </asp:GridView>
        <asp:Label ID="Label1" runat="server" Text="当前页"></asp:Label>&nbsp;
        <asp:Label ID="Label2" runat="server" Text="1"></asp:Label>&nbsp;
        <asp:Label ID="Label3" runat="server" Text="总页数"></asp:Label>&nbsp;
        <asp:Label ID="Label4" runat="server" Text="Label"></asp:Label>&nbsp;
        <asp:LinkButton ID="LinkButton1" runat="server" onclick="LinkButton1_Click">首页</asp:LinkButton>&nbsp;
        <asp:LinkButton ID="LinkButton2" runat="server" onclick="LinkButton2_Click">上一页</asp:LinkButton>&nbsp;
        <asp:LinkButton ID="LinkButton3" runat="server" onclick="LinkButton3_Click">下一页</asp:LinkButton>&nbsp;
        <asp:LinkButton ID="LinkButton4" runat="server" onclick="LinkButton4_Click">尾页</asp:LinkButton>

后台代码：

   protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            databind();
        }

    }
    public void databind()
    {
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Conn"].ToString());
        SqlCommand cmd = new SqlCommand("SELECT * FROM CUSTOMERS", con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);
        PagedDataSource ps = new PagedDataSource();
        ps.DataSource = ds.Tables[0].DefaultView;
        ps.AllowPaging = true;
        ps.CurrentPageIndex = int.Parse(this.Label2.Text) - 1;
        this.Label4.Text = ps.PageCount.ToString();
        this.LinkButton1.Enabled = true;
        this.LinkButton2.Enabled = true;
        this.LinkButton3.Enabled = true;
        this.LinkButton4.Enabled = true;
        if (this.Label2.Text == "1")
        {
            this.LinkButton1.Enabled = false;
            this.LinkButton2.Enabled = false;
        }
        if (this.Label2.Text == this.Label4.Text)
        {
            this.LinkButton3.Enabled = false;
            this.LinkButton4.Enabled = false;
        }
        this.GridView1.DataSource = ps;
        this.GridView1.DataBind();
    }
    protected void LinkButton1_Click(object sender, EventArgs e)
    {
        this.Label2.Text = "1";
        databind();
    }
    protected void LinkButton2_Click(object sender, EventArgs e)
    {
        this.Label2.Text = Convert.ToString( Convert.ToInt32(this.Label2.Text) - 1);
        databind();
    }
    protected void LinkButton3_Click(object sender, EventArgs e)
    {
        this.Label2.Text = Convert.ToString( Convert.ToInt32(this.Label2.Text) + 1);
        databind();
    }
    protected void LinkButton4_Click(object sender, EventArgs e)
    {
        this.Label2.Text = this.Label4.Text;
        databind();
    }