GridView自动排序

GridView自带了数据排序功能。在设计视图下，只能对GridView的排序数据列和排序方向进行静态设置。在后台程序中，则需要用Attributes方式对GridView的这两个属性进行动态设置。

示例如下：
（前台）

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
// 设定初始排序参数值

// 错误的属性设置方法：SortExpression、SortDirection均是GridView只读属性，无法直接赋值。
//this.GridView1.SortExpression = "id";
//this.GridView1.SortDirection = "ASC";

// 正确的属性设置方法
this.GridView1.Attributes.Add("SortExpression", "id");
this.GridView1.Attributes.Add("SortDirection", "ASC");

// 绑定数据源到GridView
this.BindGridView();
}
}

/// <summary>
/// GridView排序事件
/// </summary>
protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
{
// 从事件参数获取排序数据列
string sortExpression = e.SortExpression.ToString();

// 假定为排序方向为“顺序”
string sortDirection = "ASC";

// “ASC”与事件参数获取到的排序方向进行比较，进行GridView排序方向参数的修改
if (sortExpression == this.GridView1.Attributes["SortExpression"])
{
//获得下一次的排序状态
sortDirection = (this.GridView1.Attributes["SortDirection"].ToString() == sortDirection ? "DESC" : "ASC");
}

// 重新设定GridView排序数据列及排序方向
this.GridView1.Attributes["SortExpression"] = sortExpression;
this.GridView1.Attributes["SortDirection"] = sortDirection;

this.BindGridView();
}

/// <summary>
/// 绑定到GridView
/// </summary>
private void BindGridView()
{
// 获取GridView排序数据列及排序方向
string sortExpression = this.GridView1.Attributes["SortExpression"];
string sortDirection = this.GridView1.Attributes["SortDirection"];

// 调用业务数据获取方法
DataTable dtBind = this.getDB();

// 根据GridView排序数据列及排序方向设置显示的默认数据视图
if ((!string.IsNullOrEmpty(sortExpression)) && (!string.IsNullOrEmpty(sortDirection)))
{
dtBind.DefaultView.Sort = string.Format("{0} {1}", sortExpression, sortDirection);
}

// GridView绑定并显示数据
this.GridView1.DataSource = dtBind;
this.GridView1.DataBind();
}

/// <summary>
/// 获取数据源的方法
/// </summary>
/// <returns>数据源</returns>
private DataTable getDB()
{
DataTable dt = new DataTable();

dt.Columns.Add("id");
dt.Columns.Add("name");
dt.Columns.Add("age");

dt.Rows.Add(new object[] { "000001", "hekui", "26" });
dt.Rows.Add(new object[] { "000002", "zhangyu", "26" });
dt.Rows.Add(new object[] { "000003", "zhukundian", "27" });
dt.Rows.Add(new object[] { "000004", "liyang", "25" });
dt.Rows.Add(new object[] { "000005", "caili", "27" });

return dt;
}
}