using System.Diagnostics;
private void button1_Click(object sender, EventArgs e)
{
Process vProcess = new Process();
vProcess.StartInfo.FileName = "cmd.exe";
vProcess.StartInfo.UseShellExecute = false;
vProcess.StartInfo.RedirectStandardInput = true;
vProcess.StartInfo.RedirectStandardOutput = true;
vProcess.StartInfo.RedirectStandardError = true;
vProcess.StartInfo.CreateNoWindow = false;
vProcess.Start();
vProcess.StandardInput.WriteLine(@"dir d:\");
vProcess.StandardInput.WriteLine("exit");
textBox1.Text = vProcess.StandardOutput.ReadToEnd();
vProcess.Close();
}