Redirect to login and redirection to same page using querystring

In Login.aspx.vb Login button click event

If Not Request.QueryString("Ref") = Nothing Then
Response.Redirect(Request.QueryString("Ref"), False)
Else
Response.Redirect("default.aspx", False)
End If

In all other pages' load event
If Session("UserID") Is Nothing Then
'Response.Redirect("Login.aspx", False)
Response.Redirect("Login.aspx?Ref=" & HttpContext.Current.Request.Url.PathAndQuery.ToString(), False)
Else
.
.
.
.
.
End if