Explicit IDisposable

using System;

class D : IDisposable
{
  void IDisposable.Dispose() { }
}

static class Program
{
  static void Main() {
    var d = new D();

    // #1 Looks like typecast
    ((IDisposable)d).Dispose();

    // #2 Temporary variable w/o typecast
    IDisposable dd = d;
    dd.Dispose();

    // #3 - Calling extension
    d.Dispose();
  }

  static void Dispose<T>(this T instance) where T : IDisposable {
    if(instance == null) {
      throw new ArgumentNullException("instance");
    }//if

    instance.Dispose();
  }
}