February 5, 2014 15:41 by
PeterIn this example i am showing how to use Cross Page Posting or Postback In ASP.NET 2.0, 3.5, 4.0 Using C#. Cross Page posting is used to submit a form on one page (say default.aspx) and retrieve values of controls of this page on another page (say Default2.aspx). There are two ways we can use cross page postsbacks in ASP.NET.
1st method
In this i've created a Default.aspx page with two textbox and one button , button click will post back to Default2.aspx and there we will retrieve and show values of both textboxes Html source of Default.aspx page is like
<%@ Page Language="C#" AutoEventWireup="true"
CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!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>
First Name:
<asp:TextBox ID="txtFirstName" runat="server">
</asp:TextBox><br /><br />
Last Name:
<asp:TextBox ID="txtLastName" runat="server">
</asp:TextBox><br /><br /><br />
<asp:Button ID="btnSubmit" runat="server"
OnClick="btnSubmit_Click"
PostBackUrl="~/Default2.aspx"
Text="Submit to Second Page" /><br />
</div>
</form>
</body>
</html>
Don't forget to set PostBackUrl Property of Button
PostBackUrl="~/Default2.aspx"
Now to retrieve values of textBoxes on Default2.aspx page, write below mentioned code in Page_Load event of second page (Default2.aspx)
protected void Page_Load(object sender, EventArgs e)
{
//Check whether previous page is cross page post back or not
if (PreviousPage != null && PreviousPage.IsCrossPagePostBack)
{
TextBox txtPbFirstName = (TextBox)PreviousPage.FindControl("txtFirstName");
TextBox txtPbLastName = (TextBox)PreviousPage.FindControl("txtLastName");
Label1.Text = "Welcome " + txtPbFirstName.Text + " " + txtPbLastName.Text;
}
else
{
Response.Redirect("Default.aspx");
}
}
If you are using masterpages then you need to write code to FindControl as mentioned below
ContentPlaceHolder exampleHolder =(ContentPlaceHolder)Page.PreviousPage.Form.FindControl ("Content1"));
TextBox txtExample = exampleHolder.FindControl("txtFirstName");
2nd Method
Using Property to expose and Consume values of TextBox
If we are using this method then we don't need to use FindControl method at all
For this we need to create property in code behind of the page to be cross page post back (Default.aspx)
Html of the page needs no changes ,
C# code behind for Default.aspx
public TextBox pbTxtFirstName
{
get
{
return txtFirstName;
}
}
public TextBox pbTxtLastName
{
get
{
return txtLastName;
}
}
Now write this code in page_Load event of second page to retrieve values of controls
protected void Page_Load(object sender, EventArgs e)
{
if (PreviousPage != null && PreviousPage.IsCrossPagePostBack)
{
Label1.Text = "Welcome " + PreviousPage.pbTxtFirstName.Text + " " + PreviousPage.pbTxtLastName.Text;
}
else
{
Response.Redirect("Default.aspx");
}
}