C# WinApp System.IO.File.CreateText Error บอกว่าไม่เห็น path ทั้งๆที่เพิ่งสร้างไป

void CreatePath(string _path)
        {
            if (!(System.IO.Directory.Exists(_path)))
            {

                System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo
                {
                    WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden,
                    FileName = "cmd.exe",
                    Arguments = "/c md " + Convert.ToChar(34) + _path + Convert.ToChar(34)
                };
                System.Diagnostics.Process process = new System.Diagnostics.Process { StartInfo = startInfo };
                process.Start();
            }
        }
private void button4_Click(object sender, EventArgs e)
        {
            int bb = 1;
            string CODE;
            for (int b = 1; b < 10; b++)
            {
                CreatePath(txtTarget.Text + "\\" + b);// สร้างโฟลเดอร์
            }
                for (int i = 0; i < dataGridView1.RowCount - 1; i++)
                {
                    do
                    {

                        song++;
                        if (song > 60000)
                        {
                            song = 0;
                            bb++;
                        }
                        CODE = bb + string.Format("{0:00000}", song);
                        _fileSong = txtTarget.Text + "\\" + bb + "\\" + CODE + ".AVI";
                        _fileSNF = txtTarget.Text + "\\" + bb + "\\" + CODE + ".SNF";
                    } while (System.IO.File.Exists(_fileSong));
                    System.IO.File.CreateText(_fileSNF).Dispose();
                }
        }