Hi Friend,
there are multiple way's you can do it.
1) using Session object . once authentications is done then you will Store user name in Session and get it on another page.
LIke ,
Set Session variable.
Session["username"] = " your user name variable";
Get session variable
string username = Session["username"].tostring();
2) using Query string.
you can pass user name into Query string in url
Like
Set Query string value
responce.Redirect("username.aspx?value="+ username);
get QS on another page
if (Request.QueryString("value") != null)
{
string username = Request.QueryString("value").tostring();
}
there are also other ways to pass the value between two page call. above two method are mostly used.
hope this will help...