Articles → .NET → Difference Between Response.Redirect And Server.Transfer

Difference Between Response.Redirect And Server.Transfer

1. Visual Studio 2008 or Visual Studio 2005 installed on your computer.
2. Hands on experience on creating a web application.

Creating A Web Application

1. Create ASP.NET web application with C# as programming language with name WebApp1.
2. Add 2 pages page1.aspx and page2.aspx
3. On page1.aspx add a textbox (TextBox1) and 2 button controls i.e. Button1 and Button2.

Difference

1. In case of Server.Transfer you cannot send the user to external sites but by using Response.Redirect you can send the user to external site.
Elaboration

On the "Button 1" click event, write the following code.



Response.Redirect(“http://www.gyansangrah.com”);



On the "Button 2" click event.



Server.Transfer(“http://www.gyansangrah.com”);



Run the application. You will get the following output.



Event	Output
"Button 1" click	Page is navigated to http://www.gyansangrah.com.
"Button 2" click	Invalid path for child request 'http://www.gyansangrah.com'. A virtual path is expected.



Change the code in "Button 2" click to



Server.Transfer(“Page2.aspx”);



Run the application again and click on the "Button 2". Page is navigated to Page2.aspx.

From the above elaboration it is clear that by using Server.Transfer you cannot redirect the page to external sites.


2. Server.Transfer maintains the original URL in the browser.
Elaboration



Event	URL
"Button 1" click	http://localhost/WebApp1/Page2.aspx
"Button 2" click	http://localhost/WebApp1/Page1.aspx



From the above elaboration it is clear that by using Server.Transfer maintains the original URL in the browser.


3. Server.Transfer saves server resources.
Elaboration

On the click of Button1 add the following code



Response.Write("Testing123")
Response.Redirect("Page2.aspx")
Response.Write("Testing444")



On the click of Button2 add the following code



Response.Write("Testing123")
Server.Transfer("Page2.aspx")
Response.Write("Testing444")



Run the application. You will get the following output.



Event	Output
"Button 1" click	Page is redirected to Page2.aspx and on the page Testing444 is written
"Button 2" click	URL doesn’t change but page is redirected to Page2.aspx and on the page Testing123 and Testing444 is written



In case of Response.Redirect a new HTTP request goes to the server and a new page is displayed on the browser but in case of Server.Transfer focus is changed to Page2.aspx without sending request to the server. In this way Server.Transfer saves a HTTP request to the server so in this way Server.Transfer saves server resources.


4. You can access the contents of previous page using Server.Transfer, but not in case of Response.Redirect.
Elaboration

Write following code on Button1 click



Response.Redirect("Page2.aspx")



Write following code on Button2 click



Server.Transfer("Page2.aspx")



On page load of Page2.aspx write following code. This code is to access the content of previous page.



Dim poster As Page = Me.PreviousPage
Dim txtTest As TextBox = CType(poster.FindControl("TextBox1"), TextBox)
Response.Write(txtTest.Text)



Run the application. Add some text in the textbox. Click Button1. Page is redirected to Page2.aspx. But you will get an error because in case of Response.Redirect Me.PreviousPage is null.

Now go back to previous page again. Add some text in the textbox. Click Button2. You can see that the text entered in the textbox is displayed on page load of page2.aspx.


5. If PreserveForm Paramater in Server.Transfer is set to true then you can access the values of controls by using Request.Form
Elaboration

On Click on Button2 write following code



Server.Transfer("Page2.aspx",True)



On page load of Page2.aspx add the following code



Response.Write(Request.Form[“TextBox1”]);



Run the application. Add some text in TextBox. Click Button1. Page is navigated to Page2.aspx and you will get an error - Object reference is not set to an instance of an object.

Now go back to Page1.aspx. Enter some text in the textbox and click button2. Page is navigated to Page2.aspx and you can see the text of Textbox written on the page load of Page2.aspx. Change the code of Button2 to



Server.Transfer("Page2.aspx",False)



This boolean variable preserveForm is set to false.

Again run the application. Enter some text in the textbox and click Button2. Page is navigated to Page2.aspx and you will get an error - Object reference is not set to an instance of an object.

So it is clear from the above elaboration the if we set preserveForm to true then we can access the value of controls of previous page using Request.Form.