using System;
using System.Windows.Forms;

namespace ConsoleApplication2
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            using (var openFileDialog = new OpenFileDialog())
            {
                openFileDialog.InitialDirectory = "c:\\";
                openFileDialog.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";
                openFileDialog.FilterIndex = 2;
                openFileDialog.RestoreDirectory = true;

                if (openFileDialog.ShowDialog() == DialogResult.OK)
                {
                   Console.WriteLine(openFileDialog.FileName);
                }
            }
        }
    }
}