Memory leak, Dispose() and Using statement (5)

Some conclusions. Just add something useful in the end of this series of post although most of people have known it.

Tip1:
c# provides a statement which provides a convenient syntax that ensures the correct use of IDisposable objects. It is 'using' statement.

Copied from MSDN "http://msdn.microsoft.com/en-us/library/yh598w02.aspx".
"As a rule, when you use an IDisposable object, you should declare and instantiate it in a using statement. The using statement calls the Disposemethod on the object in the correct way, and (when you use it as shown earlier) it also causes the object itself to go out of scope as soon as Dispose is called. Within the using block, the object is read-only and cannot be modified or reassigned."


An example from MSDN is like followings and MSDN also gives code of the example in the compile time.
Example about how to use 'using' statement.

C#

using (Font font1 = new Font("Arial", 10.0f)) 
{
    byte charset = font1.GdiCharSet;
}

Code in the compile time.

C#

{
  Font font1 = new Font("Arial", 10.0f);
  try
  {
    byte charset = font1.GdiCharSet;
  }
  finally
  {
    if (font1 != null)
      ((IDisposable)font1).Dispose();
  }
}

Tip2:

Call Dispose() explicitly if you can not use 'using' statement. I saw a case 'using' statement can not be used. At this time, use the try/finally pattern to make sure the unmanaged resources are disposed of even if an exception interrupts your application.

Tip3:

Do not dispose an passed in object. The reason is also obvious. The passed in parameter could be used by the calling method again.