[网络收集]使用PostBackUrl属性实现跨页面传值

首先是PostBackUrl,像Button、LinkButton等控件都有这个属性。看下面的例子:

Demo.aspx

程序代码 程序代码

<asp:HiddenField ID="Hidden_ID" runat="server" Value="Test" />
<asp:LinkButton ID="LinkButton1" runat="server" PostBackUrl="Test.aspx">LinkButton</asp:LinkButton>
<asp:Button ID="Button1" runat="server" Text="Button" PostBackUrl="Test.aspx" />



Test.aspx.cs

程序代码 程序代码

protected void Page_Load(object sender, EventArgs e)
{
     if (PreviousPage != null)
     {
         HiddenField Hidden_ID = (HiddenField)PreviousPage.FindControl("Hidden_ID");
         if (Hidden_ID != null)
         {
             Label1.Text = Hidden_ID.Value;
         }
     }
     else
     {
         Label1.Text = "null";
     }
}



Server.Transfer是一个基于服务器的方法,而PostBackUrl是基于客户端的。从这个意义上来讲,跨页面传送比Server.Transfer更加的便捷,有利于提高服务器的性能,减少了处理步骤。除开这一点,两者还是非常相似的,不过在ASP.NET 2.0中,跨页面传送显然是更好的选择。

如果要在后续页面中判断PerviousPage所引用的页面是通过跨页面提交而来的还是通过Server.Transfer方法传送而来的,可以通过IsCrossPagePostBack属性来进行判断。

程序代码 程序代码

if (PreviousPage != null)
{
     if (PreviousPage.IsCrossPagePostBack == true)
     {
         Response.Write("Cross-page post.");
     }
}
else
{
     Response.Write("Not a cross-page post.");

}

 

一、用FindControl方法获取发送页的值:

Page1.aspx

<% @ Page Language = " C# " AutoEventWireup = " true " CodeFile = " Page1.aspx.cs " Inherits = " Page1 " %>

<! 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 > Untitled Page </ title >
</ head >
< body >
    
< form id ="form1" runat ="server" >
    
< div >
        
< asp:TextBox ID ="TextBox1" runat ="server" ></ asp:TextBox >
        
< asp:Calendar ID ="Calendar1" runat ="server" ></ asp:Calendar >
        
< asp:Button ID ="Button1" runat ="server" Text ="Button" PostBackUrl ="~/Page2.aspx" />
    
</ div >
    
</ form >
</ body >
</ html >

 

Page2.aspx.cs:

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;


public partial class Page2 : System.Web.UI.Page
{
    
protected void Page_Load( object sender, EventArgs e)
     {
         TextBox pp_Textbox1;
         Calendar pp_Calendar1;

         pp_Textbox1
= (TextBox)PreviousPage.FindControl( " Textbox1 " );
         pp_Calendar1
= (Calendar)PreviousPage.FindControl( " Calendar1 " );

         Response.Write(pp_Textbox1.Text
+ " - " + pp_Calendar1.SelectedDate.ToShortDateString());
     }
}

二、从属性中获得控件的值:

Page1.aspx

<% @ Page Language = " C# " AutoEventWireup = " true " CodeFile = " Page1.aspx.cs " Inherits = " Page1 " %>

<! 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 > Untitled Page </ title >
</ head >
< body >
    
< form id ="form1" runat ="server" >
    
< div >
        
< asp:TextBox ID ="TextBox1" runat ="server" ></ asp:TextBox >
        
< asp:Calendar ID ="Calendar1" runat ="server" ></ asp:Calendar >
        
< asp:Button ID ="Button1" runat ="server" Text ="Button" onclick ="Button1_Click" PostBackUrl ="~/Page2.aspx" />
    
</ div >
    
</ form >
</ body >
</ html >



Page2.aspx:

注意使用的是PreviousPageType指令:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Page2.aspx.cs" Inherits="Page2" %>
<%@ PreviousPageType VirtualPath="~/Page1.aspx" %>

<!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>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
   
    </div>
    </form>
</body>
</html>

 

Page2.aspx.cs

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;


public partial class Page2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Response.Write(PreviousPage.pp_TextBox1.Text + " - " +

PreviousPage.pp_Calendar1.SelectedDate.ToShortDateString());
    }
}

如果在未处理Page1.aspx之前。有人请求了Page2.aspx,该怎么办?使用PreviousPage.IsCrossPagePostBack属性。注意:须先判断

PreviousPage是否为空,否则出报错:未将对象的引用设置到对象的实例

 

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;


public partial class Page2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (PreviousPage != null)
        {
            if (PreviousPage.IsCrossPagePostBack)
            {
                Response.Write(PreviousPage.pp_TextBox1.Text + " - " +

PreviousPage.pp_Calendar1.SelectedDate.ToShortDateString());
            }
            else
            {
                Response.Redirect("Page1.aspx");
            }
     

摘自http://hi.baidu.com/qgbmxxf/blog/item/c51dbe51d34d392a43a75bc5.html

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