ASP.NET – Server.Transfer v/s Response.Redirect

Introduction This article tell you the difference between Server.Transfer and Response.Redirect.

Server.Transfer v/s Response.Redirect Both “Server” and “Response” are objects of ASP.NET. Server.Transfer and Response.Redirect both are used to transfer a user from one page to another page. Both are used for the same purpose but still there are some differences are there between both that are as follows:

Syntactically both are different, if you want to transfer the user to a page named newpage.aspx then syntax for both methods will be, Response.Redirect(“newpage.aspx”) and Server.Transfer(“newpage.aspx”)

Response.Redirect involves a roundtrip to the server whereas Server.Transfer conserves server resources by avoiding the roundtrip. It just changes the focus of the webserver to a different page and transfers the page processing to a different page. Roundtrip means in case of Response.Redirect it first sends the request for the new page to the browser then browser sends the request for the new page to the webserver then after your page changes But in case of Server.Transfer it directly communicate with the server to change the page hence it saves a roundtrip in the whole process. If you are using Server.Transfer then you can directly access the values, controls and properties of the previous page which you can’t do with Response.Redirect. Suppose you are currently on the Page1.aspx and now you are transferring the user to the Page2.aspx using Response.Redirect then When the Page2 page is requested, Page1 has been flushed from the server’s memory and no information can be retrieved about it unless the developer explicitly saved the information using some technique like session, cookie, application, cache etc. But in case of Server.Transfer variables can stay in scope and Page2 can read properties directly from Page1 because it’s still in memory, as you know the Server.Transfer just changes the focus from page1 to page2 So in this case browser doesn’t know that any change is happen there that’s why with this method you can access the information about the previous page. Response.Redirect changes the URL in the browser’s address bar. So they can be bookmarked. Whereas Server.Transfer retains the original URL in the browser’s address bar. It just replaces the contents of the previous page with the new one. Actually in case of Server.Transfer it directly contact with the webserver for the new page request, it doesn’t involve the browser, so that browser doesn’t know that there is any change happen. But in case of Response.Redirect as you know it first send the request (for new page) to the browser then further processing will be performed, so here browser knows that yes there is some change in the browser window that’s why it changes the URL in the address bar. So, the matter “No change of address in the browser address bar” This is a good thing if you see it from security point of view but it creates problem in case if you refresh your page or in case you want to add bookmark of that page. In case of refresh and bookmark it will add perform both the action with the URL currently present in the address bar, but as you know Server.Transfer doesn’t changes the URL, so sometimes it creates problem. Response.Redirect can be used for both .aspx and html pages whereas Server.Transfer can be used only for .aspx pages and is specific to ASP and ASP.NET. With Response.Redirect you can redirect the user to the both type of pages .html or .aspx like below, Response.Redirect(“mypage.html”) OR Response.Redirect(“OtherPage.aspx”) But in case of Server.Transfer you can only work with .asp or .aspx page like below Server.Transfer(“mypage.asp”) OR Server.Transfer(“OtherPage.aspx”) Response.Redirect can be used to redirect a user to an external websites. Server.Transfer can be used only on sites running on the same server. You cannot use Server.Transfer to redirect the user to a page running on a different server. Suppose on some action on the webpage I want to redirect my user to the http://www.yahoo.com so with Response.Redirect you can redirect your user to the external site, but in case of Server.Transfer you can only work with the .asp or .aspx pages that are present in your site. Now the question is which to use and when to use? Mostly the Server.Transfer method is preferable to use because Server.Transfer is faster since there is one less roundtrip, but in some people say that Server.Transfer is not recommended since the operations typically flow through several different pages due to which you lose the correct URL of the page, but again all depends on your requirement. Server.Transfer also allows for more flexibility since you can use HTTPContext.Items to pass variables between pages so, use Server.Transfer when you need to pass context items. Otherwise use Response.Redirect so the user will always see the correct URL in the address bar. I mentioned the most common differences here if anyone knows any other difference other than these then please give your comments. Thank you, Reference : Prashant Pandey (TechAhead)

*******