What is difference between Dispose and Using?

Question

What is difference between Dispose and Using? How to decide which one to use? Which is better option of garbage collection?

Akhil Mittal · Answer

From MSDN: The using statement ensures that Dispose is called even if an exception occurs while you are calling methods on the object. You can achieve the same result by putting the object inside a try block and then calling Dispose in a finally block; in fact this is how the using statement is translated by the compiler. using (DisposableTest obj = new DisposableTest()) { // some code throwing exception here. } is equivalent to { DisposableTest obj = new DisposableTest(); try { // some code throwing exception here. } finally { obj.Dispose(); } } Note the extra curly braces to create the limited scope for the object

Vulpes · Answer

The 'using' statement is used in C# and VB with an object which implements the IDisposable interface to ensure that the Dispose() method is called automatically on that object (even if there's an exception) when the 'using' statement terminates. It's therefore a convenient alterative to calling the Dispose() method 'manually' within a try/catch/finally statement. The Dispose() is designed to clear up 'unmanaged' resources used by an object such as file handles database connections and the like as a prelude to the object itself being garbage collected. It's preferable from a GC point of view to use the 'using' statement rather than calling Dispose() manually as this ensures that the object (if declared at the head of the statement) will automatically go out of scope when the 'using' statement ends and will become eligible for garbage collection without any delay. Otherwise you have to remember to call Dispose() and then set the object variable to null manually. Failure to take these steps may lead to a resource leak or to the object hanging around in memory longer than it needs to.