Convert using code

using (MyResource myRes = new MyResource())
{
    myRes.DoSomething();

}

==

MyResource myRes= new MyResource();
try
{
    myRes.DoSomething();
}
finally
{
    // Check for a null resource.
    if (myRes!= null)
        // Call the object's Dispose method.
        ((IDisposable)myRes).Dispose();
}

this.System.IDisposable.Dispose()

((IDisposable)this).Dispose();