=======default.aspx=========
<%@ Page Language="C#" %>
<%@ Import Namespace="System.Data" %>
<html>
<head>
<title>用于页面 UI 状态值的 ViewState</title>
</head>
<body>
<form id="Form1" runat="server">
<h3>
在 ViewState 中存储非控件状态
</h3>
<p>
此示例将一列静态数据的当前排序顺序存储在 ViewState 中。<br/>
单击列标题中的链接，可按该字段排序数据。<br/>
再次单击该链接，将按相反顺序排序。
<br/>
<br/>
<br/>
<asp:DataGrid ID="DataGrid1" runat="server" OnSortCommand="SortGrid" BorderStyle="None"
BorderWidth="1px" BorderColor="#CCCCCC" BackColor="White" CellPadding="5" AllowSorting="True">
<HeaderStyle Font-Bold="True" ForeColor="White" BackColor="#006699"></HeaderStyle>
</asp:DataGrid>
</p>
</form>
</body>
</html>
<script runat="server">
// 在 ViewState 中跟踪 SortField 属性
string SortField
{
get
{
object o = ViewState["SortField"];
if (o == null)
{
return String.Empty;
}
return (string)o;
}
set
{
if (value == SortField)
{
// 与当前排序文件相同，切换排序方向
SortAscending = !SortAscending;
}
ViewState["SortField"] = value;
}
}
// 在 ViewState 中跟踪 SortAscending 属性
bool SortAscending
{
get
{
object o = ViewState["SortAscending"];
if (o == null)
{
return true;
}
return (bool)o;
}
set
{
ViewState["SortAscending"] = value;
}
}
void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
BindGrid();
}
}
void BindGrid()
{
// 获取数据
DataSet ds = new DataSet();
ds.ReadXml(Server.MapPath("TestData.xml"));
DataView dv = new DataView(ds.Tables[0]);
// 应用排序过滤器和方向
dv.Sort = SortField;
if (!SortAscending)
{
dv.Sort += " DESC";
}
// 绑定网格
DataGrid1.DataSource = dv;
DataGrid1.DataBind();
}
void SortGrid(object sender, DataGridSortCommandEventArgs e)
{
DataGrid1.CurrentPageIndex = 0;
SortField = e.SortExpression;
BindGrid();
}
</script>
=========TestData.xml=========
<?xml version="1.0" standalone="yes"?>
<NewDataSet>
<Table>
<pub_id>0736</pub_id>
<pub_name>New Moon Books</pub_name>
<city>Boston</city>
<state>MA</state>
<country>USA</country>
</Table>
<Table>
<pub_id>0877</pub_id>
<pub_name>Binnet & Hardley</pub_name>
<city>Washington</city>
<state>DC</state>
<country>USA</country>
</Table>
<Table>
<pub_id>1389</pub_id>
<pub_name>Algodata Infosystems</pub_name>
<city>Berkeley</city>
<state>CA</state>
<country>USA</country>
</Table>
<Table>
<pub_id>1622</pub_id>
<pub_name>Five Lakes Publishing</pub_name>
<city>Chicago</city>
<state>IL</state>
<country>USA</country>
</Table>
<Table>
<pub_id>1756</pub_id>
<pub_name>Ramona Publishers</pub_name>
<city>Dallas</city>
<state>TX</state>
<country>USA</country>
</Table>
<Table>
<pub_id>9901</pub_id>
<pub_name>GGG&G</pub_name>
<city>Muenchen</city>
<country>Germany</country>
</Table>
<Table>
<pub_id>9952</pub_id>
<pub_name>Scootney Books</pub_name>
<city>New York</city>
<state>NY</state>
<country>USA</country>
</Table>
<Table>
<pub_id>9999</pub_id>
<pub_name>Lucerne Publishing</pub_name>
<city>Paris</city>
<country>France</country>
</Table>
</NewDataSet>
