How to run C# app on Mac from command line?

mcs
mono
###################
mcs - C# compiler
mono - Mono runtime

vim monoapp.cs

using System;                 // Importing namespace

class Test                    // Class declaration
{
  static void Main()          // Method declaration
  {
    //int x = 12 * 30;          // Statement 1
    Console.WriteLine ("Hello form mono!");    // Statement 2
  }                           // End of method
}

mcs monoapp.cs

mono monoapp.exe

Hello from mono!

using System;
using System.Drawing;
using System.Windows.Forms;

public class HelloWorld : Form
{
    static public void Main ()
    {
        Application.Run (new HelloWorld ());
    }

    public HelloWorld ()
    {
        Button b = new Button ();
        b.Text = "Click Me!";
        b.Click += new EventHandler (Button_Click);
        Controls.Add (b);
    }

    private void Button_Click (object sender, EventArgs e)
    {
        MessageBox.Show ("Button Clicked!");
    }
}

mcs -pkg:dotnet  win_mono_app.cs

mono win_mono_app.exe