system.io Path Combine
namespace: System.IO
//c#
var folder = "C:\temp";
var fileName = "note.txt";
var completePath = Path.Combine(folder, filename);
//return: "C:\temp\note.txt"
//vb
Dim folder As String = "C:\temp";
Dim fileName As String = "note.txt";
Dim completePath As String = Path.Combine(folder, filename);
//return: "C:\temp\note.txt"