CODEWITHSUNDEEP
c#.net
Leo Vo
Leo Vo

Reputation: 10330

What cases to use Application Domain?

I read the concept about Application Domain in .NET. However, I don't know when to use it. A application domain is working as a thread in a process. A process will have more than or equal one application domain. However, I can deploy a process with multi-threading without using application domain.

Anyone can tell some examples to use it in practice. There are source code for examples are good. And I wonder that there are any Microsoft's applications to use this technology.

Thanks.

Upvotes: 4

Views: 870

Answers (3)

Polity
Polity

Reputation: 15130

MSDN really gives a clear picture here of what AppDomains are actually for: http://msdn.microsoft.com/en-us/library/system.appdomain.aspx

Application domains, which are represented by AppDomain objects, help provide isolation, unloading, and security boundaries for executing managed code.

Use application domains to isolate tasks that might bring down a process. If the state of the AppDomain that's executing a task becomes unstable, the AppDomain can be unloaded without affecting the process. This is important when a process must run for long periods without restarting. You can also use application domains to isolate tasks that should not share data.

If an assembly is loaded into the default application domain, it cannot be unloaded from memory while the process is running. However, if you open a second application domain to load and execute the assembly, the assembly is unloaded when that application domain is unloaded. Use this technique to minimize the working set of long-running processes that occasionally use large DLLs.

Upvotes: 2

Zenwalker
Zenwalker

Reputation: 1919

I would like to explain the usage of AppDomains in a real world design problem from one of my earlier project.

Basically that project is a port scanner for some information. So we had 6 ports, and we are suppose to scan 6 ports in parallel. Of course we could have used threads, but then isolation would not be possible at all. We wanted every port functionality i.e scanning should be completely isolated and even its data storage and other functionality to be independent.

So what we did was, we used AppDomain concept in loading on of our dll which does this scanning job and few more (proprietary logics) into 6 AppDomains we had created for each port. Infact, this dll spawns more thread internally to do various jobs once you scan the port for some data. Hence we have completely isolated each port scanning and when user wants to stop scanning for one of the port (via UI selection) then we just have to gracefully unload this AppDomain.

Hope it was some help to you :)

Upvotes: 2

Toto
Toto

Reputation: 56

If you load a dll in your main AppDOmain you can't unlod it. But if you load the .dll in an AppDOmain you can unload the AppDomain and so unload the dll. Like that you can load and unload dll.

And with Addin I saw that you can load plugin in AppDomain with security, in order that the plugin can not compromise the main software security.

Upvotes: 2

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