Difference Between Response.Redirect() and Server.Transfer() Methods in ASP.NET

Both Response.Redirect and Server.Transfer methods are used to transfer a user from one web page to another web page. Both methods are used for the same purpose, but still there are some differences as follows.

The Response.Redirect method redirects a request to a new URL and specifies the new URL while the Server.Transfer method for the current request, terminates execution of the current page and starts execution of a new page using the specified URL path of the page.

Both Response.Redirect and Server.Transfer have the same syntax like:

Response.Redirect("UserDetail.aspx");
Server.Transfer("UserDetail.aspx");

Using the Code

When you use Server.Transfer, then the previous page also exists in server memory while in theResponse.Redirect method, the previous page is removed from server memory and loads a new page in memory. Let's see an example.

We add some items in the context of the first page "UserRegister.aspx" and thereafter the user transfers to another page "UserDetail.aspx" using Server.Transfer on a button click. The user will then be able to request data that was in the context because the previous page also exists in memory. Let's see the code.

Code of the UserRegister.aspx.cs page:


using System;
public partial class UserRegister : System.Web.UI.Page
{
    protected void btn_Detail_Click(object sender, EventArgs e)
    {
        Context.Items.Add("Name", "Sandeep Singh Shekhawat");
        Context.Items.Add("Email", "sandeep.shekhawat88@gmail.com");
       Server.Transfer("UserDetail.aspx");
    }
} 

Code of the UserDetail.aspx.cs page:


 using System;
public partial class UserDetail : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            Response.Write(string.Format("My name is {0} and email address is {1}",
                                          Context.Items["Name"].ToString(),
                                          Context.Items["Email"].ToString()));
        }
        catch (NullReferenceException ex)
        {
            Response.Write(ex.Message);
        }
    }
} 

Using the code above, we can get data from the previous page to the new page by the Context.Item collection. But if you use the Response.Redirect method, then you can't get context data on another page and get an exception object as null because the previous page doesn't exist in server memory.



Figure 1.5 Null Exception by Context object

Mostly the Server.Transfer method is preferable to use because Server.Transfer is faster since there is one less roundtrip, but some people say that Server.Transfer is not recommended since the operations typically flow through several different pages causing a loss of the correct URL of the page, but again it all depends on your requirement.

It is not a complete list. I wrote the basic differences between these two. If you know more differences, then please provide them in the comments.