Using Statement

What Does Using Statement Mean?

A using statement in C# syntax is a key way to handle the disposal of resources in code, which may be effective in dealing with memory allocation issues such as memory leaks. However, the idea of using a using statement only applies to items that implement something called IDisposable.


In object-oriented programming (OOP), a dispose pattern is a process where an object holds a resource (or multiple resources) and then the resource is released via a method.

Experts characterize some dispose methods as “manual” in contrast to some “automatic” memory cleanup processes that may also be involved in a codebase.

Techopedia Explains Using Statement

In C# syntax, the programming language has something called "garbage collection" that deals with disposal of resources, but it is, as experts point out, "nondeterministic" (it also belongs in that category of “automatic” or non-user-generated resource disposal techniques) — it happens somewhat arbitrarily and without explicit reference.

The using statement, by contrast, allows the programmer to deliberately and explicitly reference how to dispose of some object that has been used, or more accurately, a resource for an object, that has been used by the object.

Often, the disposal will be triggered by the using statement in order to authorize disposal directly after use.

The IDisposable Process

Technically, experts point out that a using statement triggers the IDisposable process, which has only one method called “dispose.” Others show how changing compiler syntax will reveal that there's also a set of "try" and "finally" commands that can accomplish the using statement disposal trigger.

Generally speaking, the code will reference the given resource and then call the using statement to trigger the disposal.

Programmers can use a using statement in various ways.

Unit Testing

Debates around the specific tactical uses of a using statement also revolve around how garbage collection works and what the best method is for handling disposal.

Programmers may include elaborate comments that show their chosen method and technique, and how that accomplishes the decommissioning process for these items that are taking up key memory on a system.

In a way, the using statement and everything that it involves is yet another construct to help deal with the issue of “shared resources.”

In other words, the complex dance of how programs share underlying resources, tools, libraries, etc. and how this must be carefully managed in real time.

For example, seasoned developers will remember the “DLL Hell” of past years that involves problems with library interdependencies. Although IDisposable and the using statement are not often associated explicitly with libraries, there are examples of programmers using the convention this way.

“I … found this article on how to release a DLL library already loaded into a process using P-Invoke,” writes a developer at Code Project.

“It forces to unload all instances of the DLL library currently loaded within the process. Which means, that in the case you have more than one instance of the class using these external functions, all these will stop working!… we can implement our class calling the external DLL functionality with the IDisposable interface so it will automatically release the used DLL library when it goes out-of-scope or when it is finalized…”

In that context, the using statement can be a useful way for programmers to manually troubleshoot resource allocation and decommissioning of resources.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…