asp.net控件使用系列之——viewstate
html代码：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="form.aspx.cs" Inherits="form" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>无标题页</title>
<script language="javascript" type="text/javascript">
// <!CDATA[
// ]]>
</script>
</head>
<body>
<form />
</div>
</form>
<br />
</body>
</html>
button1的单击事件
foreach (HtmlTableRow row in Table1.Rows)
{
foreach (HtmlTableCell cell in row.Cells)
{
Control control = cell.Controls[0];
if (control is TextBox)
{
ViewState[control.ID] = ((TextBox)control).Text;
}
}
}
button2的单击事件
foreach (HtmlTableRow row in Table1.Rows)
{
foreach (HtmlTableCell cell in row.Cells)
{
Control control = cell.Controls[0];
if (control is TextBox)
{
string value = (string)ViewState[control.ID];
if (value != null)
{
Response.Write("value is :" + value + "<br>");
}
}
}
===================================================================
【一种比较好的设计方法】
一个最科学的方法是建立一个对应的类，然后用类来操作
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;
/// <summary>
/// Summary description for TravelPlan
/// </summary>
[Serializable]
public class TravelPlan
{
private string name, from, to;
public string Name
{
get { return name; }
set { name = value; }
}
public string From
{
get { return from; }
set { from = value; }
}
public string To
{
get { return to; }
set { to = value; }
}
public TravelPlan(string n, string f, string t)
{
name = n;
from = f;
to = t;
}
}
存值：
TravelPlan travelplan = new TravelPlan(NameTextBox.Text, FromTextBox.Text, ToTextBox.Text);
ViewState["TravelPlan"] = travelplan;
取值： TravelPlan travelplan = ViewState["TravelPlan"] as TravelPlan;
if (travelplan != null)//记得判断
{
NameTextBox.Text = travelplan.Name;
FromTextBox.Text = travelplan.From;
ToTextBox.Text = travelplan.To;
}
==================================================================
ViewState在客户端展开的时候，默认是Auto,不加密的，如果页面有限制性的表单控件才加密，所以，你可以查看，代码如下：
byte[] bytes = Convert.FromBase64String(ViewStateTextBox.Text);
DecodedDataTextBox.Text = System.Text.Encoding.ASCII.GetString(bytes);
要设置加密可以在2个地方，一个是页面代码顶部：
<%@ Page ViewStateEncryptionMode="Always" Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
还有一个在Web.config里的<system.web>与</system.web>里加:
< Page ViewStateEncryptionMode="Always" />