Sunday, November 23, 2008

Cross page is post back with different method

this is a page redirect sample (Server.Transfer, Response.Redirect, Cross-Page):

Default.aspx Code:

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Cross-Page Posting</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<center>
<h1>Cross-Page Posting</h1>
Select your favorite activity: 
<asp:DropDownList ID="ddlFavoriteActivity" runat="server" AutoPostBack="true">
<asp:ListItem Text="Eating" />
<asp:ListItem Text="Sleeping" />
<asp:ListItem Text="Programming" />
<asp:ListItem Text="Watching TV" />
<asp:ListItem Text="Sex" />
<asp:ListItem Text="Skiing" />
<asp:ListItem Text="Bicycling" />
</asp:DropDownList>
<br /><br /><br />
<asp:Button ID="btnServerTransfer" runat="server" Text="Server.Transfer"
onclick="btnServerTransfer_Click" /> 
<asp:Button ID="btnRedirect" runat="server" Text="Response.Redirect"
onclick="btnRedirect_Click" /> 
<asp:Button ID="btnCrossPage" runat="server" Text="Cross-Page Post" PostBackUrl="~/TargetPage.aspx" />
<br /><br />
IsPostBack:
<asp:Label ID="lblIsPostBack" runat="server" Text="not defined"></asp:Label>
<br />
IsCrossPagePoatBack:
<asp:Label ID="lblIsCrossPagePostBack" runat="server" Text="not defined"></asp:Label>
<br />
PreviousPage:
<asp:Label ID="lblPreviousPage" runat="server" Text="not defined"></asp:Label>
</center>
</div>
</form>
</body>
</html>

Default.aspx.cs Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.Threading;//necessary for ThreadAbortException

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
lblIsPostBack.Text = IsPostBack.ToString();
lblIsCrossPagePostBack.Text = IsCrossPagePostBack.ToString();
if (Page.PreviousPage != null)
{
lblPreviousPage.Text = Page.PreviousPage.Title;
}
}
protected void btnServerTransfer_Click(object sender, EventArgs e)
{
Server.Transfer("TargetPage.aspx");
}
protected void btnRedirect_Click(object sender, EventArgs e)
{
Response.Redirect("TargetPage.aspx");
}
}

TargetPage.aspx Code:

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Target page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<center>
<h1>Target Page</h1>
<br />
Your favorite activity is :
<asp:Label ID="lblAcyivity" runat="server" Text="unknow"></asp:Label>
<br /><br />
IsPostBack:
<asp:Label ID="lblIsPostBack" runat="server" Text="not defined"></asp:Label>
<br />
IsCrossPagePoatBack:
<asp:Label ID="lblIsCrossPagePostBack" runat="server" Text="not defined"></asp:Label>
<br />
PreviousPage:
<asp:Label ID="lblPreviousPage" runat="server" Text="not defined"></asp:Label>
<br />
Previous Page IsPostBack :
<asp:Label ID="lblPreviousPageIsPostBack" runat="server" Text="not defined"></asp:Label>
<br />
Previous Page IsCrossPagePostBack :
<asp:Label ID="lblPreviousPageCrossPagePostBack" runat="server" Text="not defined"></asp:Label>
</center>
</div>
</form>
</body>
</html>

TargetPage.aspx.cs Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class TargetPage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (Page.PreviousPage != null)
{
DropDownList ddl = (DropDownList)Page.PreviousPage.FindControl("ddlFavoriteActivity");
if (ddl != null)
{
lblAcyivity.Text = ddl.SelectedItem.ToString() + "(late-bound)";
}
}
lblIsPostBack.Text = IsPostBack.ToString();
lblIsCrossPagePostBack.Text = IsCrossPagePostBack.ToString();
if (Page.PreviousPage != null)
{
lblPreviousPage.Text = Page.PreviousPage.Title;
lblPreviousPageIsPostBack.Text = Page.PreviousPage.IsPostBack.ToString();
lblPreviousPageCrossPagePostBack.Text = Page.PreviousPage.IsCrossPagePostBack.ToString();
}
}
}
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How to Use MultiView and View

sometime we need use multiview to show some many content, this is a demo for it. Let's go!

client code:

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>This is a practice for MultiView and View</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<center>
<h1>MultiView and View</h1><br />
<asp:RadioButtonList ID="rdlView" runat="server" AutoPostBack="true"
RepeatDirection="Horizontal"
onselectedindexchanged="rdlView_SelectedIndexChanged">
<asp:ListItem Value="-1">Nothing</asp:ListItem>
<asp:ListItem Selected=True Value="0">First View</asp:ListItem>
<asp:ListItem Value="1">Second View</asp:ListItem>
<asp:ListItem Value="2">Third View</asp:ListItem>
<asp:ListItem Value="3">Last View</asp:ListItem>
</asp:RadioButtonList><br />
Current Index:
<asp:Label ID="lblCurrentIndex" runat="server"></asp:Label>
<br />
<asp:MultiView ID="MultiView1" runat="server"
onactiveviewchanged="MultiView1_ActiveViewChanged" ActiveViewIndex=0>
<asp:View ID="vwFirst" runat="server" OnActivate="ActivateView"
ondeactivate="DeactivateView">
<h2>First View</h2>
<asp:TextBox ID="txtFirstView" runat="server" />
<asp:Button ID="btnNext1" runat="server" CommandName="NextView" Text="Go to Next" />
<asp:Button ID = "btnLast" runat="server" CommandName="SwitchViewByID" CommandArgument="vwLast" Text = "Go to Last" />
</asp:View>
<asp:View ID="vwSecond" runat="server" OnActivate="ActivateView" OnDeactivate="DeactivateView">
<h2>Second View</h2>
<asp:TextBox ID="txtSecondView" runat="server"></asp:TextBox>
<asp:Button ID="btnNext2" runat="server" CommandName="NextView" Text="Go to Next" />
<asp:Button ID="btnPrevious2" runat="server" CommandName="PrevView" Text="Go to Previous" />
</asp:View>
<asp:View ID="vwThird" runat="server" OnActivate="ActivateView" OnDeactivate="DeactivateView">
<h2>Third View</h2>
<br />
<asp:Button ID="btnNext3" runat="server" CommandName="NextView" Text="Go to Next" />
<asp:Button ID="btnPrev3" runat="server" CommandName="PrevView" Text="Go to Previous" />
</asp:View>
<asp:View ID="vwLast" runat="server" OnActivate="ActivateView" OnDeactivate="DeactivateView">
<h2>Last View</h2>
<br />
<asp:Button ID="btnPrev4" runat="server" CommandName="PrevView" Text="Go to Previous" />
<asp:Button ID="btnFirst" runat="server" CommandName="SwitchViewByIndex" CommandArgument="0" Text="Go to First" />
</asp:View>
</asp:MultiView>
<br /><br />
First TextBox:
<asp:Label ID="lblFirstTextBox" runat="server"></asp:Label>
<br />
Second TextBox:
<asp:Label ID="lblSecondTextBox" runat="server"></asp:Label>
<br /><br />
<strong>
<span style="text-decoration:underline">
View Activation History:
</span>
</strong>
<br />
<asp:Label ID="lblViewActivation" runat="server"></asp:Label>
</center>
</div>
</form>
</body>
</html>

code behind:

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void Page_PreRender(object sender, EventArgs e)
{
lblCurrentIndex.Text = MultiView1.ActiveViewIndex.ToString();
}
protected void rdlView_SelectedIndexChanged(object sender, EventArgs e)
{
MultiView1.ActiveViewIndex = Convert.ToInt32(rdlView.SelectedValue);
}
protected void ActivateView(object sender, EventArgs e)
{
string str = lblViewActivation.Text;
View v = (View)sender;
str += "View " + v.ID + " activated
";
lblViewActivation.Text = str;
}
protected void DeactivateView(object sender, EventArgs e)
{
string str = lblViewActivation.Text;
View v = (View)sender;
str += "View " + v.ID + " deactivated
";
lblViewActivation.Text = str;
}
protected void MultiView1_ActiveViewChanged(object sender, EventArgs e)
{
lblFirstTextBox.Text = txtFirstView.Text;
lblSecondTextBox.Text = txtSecondView.Text;
rdlView.SelectedIndex = MultiView1.ActiveViewIndex + 1;
}
}

comments:

1. in order to save you work, you can create a event group--ActivateView,DeactivateView, these group implement the same code for you.

2. please don't write the lblCurrentIndex.Text in the Page_Load() statement, because the page will be loaded before the label updated.
Just put the lblCurrentIndex.Text code in the Page_PreRender, this is a page event handler.

such as:

protected void Page_PreRender(object sender, EventArgs e)
{
lblCurrentIndex.Text = MultiView1.ActiveViewIndex.ToString();
}
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