how to get the longitude and latitude from street address in asp.net

    This code below retrieves street address.  how can i create a function that will generate the longitude and latitude of that specific address?


   Dim conn As New Data.SqlClient.SqlConnection(ConfigurationSettings.AppSettings("connectionUSSL"))
                   
        conn.Open()
        Dim cmd As New Data.SqlClient.SqlCommand("salesquoteschecker", conn)
        cmd.CommandType = CommandType.StoredProcedure

        cmd.Parameters.Add("@ID", SqlDbType.Int).Value = Request.QueryString("id").ToString()
        Dim dr As Data.SqlClient.SqlDataReader = Nothing
 
        dr = cmd.ExecuteReader()
 
        While dr.Read()
 
            Session("street") = dr("street").ToString()
            Session("city") = dr("city").ToString()
            Session("state") = dr("state").ToString()
            Session("zip") = dr("zip").ToString()
         
           
        End While
 
        conn.Close()
        conn.Dispose()