1).
Response.Redirect simply sends a message down to the browser, telling it to move to another page. Like:
Response.Redirect("WebForm2.aspx") or Response.Redirect("http://www.karlmoore.com/")
Transferring to another page using Server.Transfer conserves server resources. Instead of telling the browser to redirect, it simply changes the "focus" on the Web server and transfers the request. This means you don't get quite as many HTTP requests coming through, which therefore eases the pressure on your Web server and makes your applications run faster.
2).
Server.Transfer can work on only those sites running on the same server, we can't use Server.Transfer to send the user to an external site. Only Response.Redirect can do that.
3).
Server.Transfer maintains the original URL in the browser. This can really help streamline data entry techniques, although it may make for confusion when debugging.
4).
The Server.Transfer method also has a second parameter—"preserveForm". If you set this to True, using a statement such as Server.Transfer("WebForm2.aspx", True), the existing query string and any form variables will still be available to the page you are transferring to.
For example, if your WebForm1.aspx has a TextBox control called TextBox1 and you transferred to WebForm2.aspx with the preserveForm parameter set to True, you'd be able to retrieve the value of the original page TextBox control by referencing Request.Form("TextBox1") or Request.QueryString("TextBox1").
One thing to be aware of is that if the first page wrote something to the Response buffer and you don’t clear it, then any output from the second page will be appended to the output of the first. This is often the cause of a weird behavior where it seems that a page is returning two different pages.
ASP.NET has a bug whereby, in certain situations, an error will occur when attempting to transfer the form and query string values. You'll find this documented at support.microsoft.com.
The unofficial solution is to set the enableViewStateMac property to True on the page you'll be transferring to, then set it back to False. This records that you want a definitive False value for this property and resolves the bug.
