How to encode query string in ASP.NET

here is syntax in vb.net for encodeing:-

code on first page from where you are using querysting

Dim firstfield As String = "firstfieldval"

Dim secondfield As String = "secondval"

Dim url As String = String.Format("secondpage.aspx?{0}&{1}", Server.UrlEncode(firstfield), Server.UrlEncode(secondfield))

Response.Redirect(url)

code on the second page to get querystring value

Dim firstf

ield As String =Server.UrlDecode(Request.QueryString"firstfieldval"))

Dim secondfield As String = Server.UrlDecode(Request.QueryString("secondval"))