ReturnUrl Question

hiiiiiiiii Alll Friends

i want to ask question about ReturnUrl, i know one this way to use it:  Response.Redirect ("Login.aspx?ReturnUrl=mypage.aspx"); But i have login control on my master page sooo i dont need to redirect them , sooo when anonymous user is visiting xyz.aspx page and he signIn from xyz.aspx then he should b redirect on xyz.aspx page after signIn successful, sooo  my question is that without using  Response.Redirect ("Login.aspx?ReturnUrl=mypage.aspx"); how can i assing value to ReturnUrl=mypage.aspx  ?, sooo freind guide me any other way to assigng value to ReturnUrl .
...