Getting all the object implementing an interface inside an application

Question

I need to get all the objects in my application that implement a given interface. How can i achieve this?

Thank you

To clarify I'm looking for instances NOT for Types.

To clarify again, i guess ill need to do something evil like get all the threads associated with my AppDomain and walk their stacks.

Again- my boss's idea... i thought of doing using IOC or AOP....

Possible duplicates: http://stackoverflow.com/questions/26733/getting-all-types-that-implement-an-interface-with-c-3-5, http://stackoverflow.com/questions/302542/how-do-i-get-all-instances-of-all-loaded-types-that-implement-a-given-interface — Cody Gray - on strike, Nov 15 '10 at 11:08
Do you want all instances of classes that implement the interface, or all classes that implement the interface? — Guffa, Nov 15 '10 at 11:08
I'm sure it is possible, the GC does exactly that every collection. I need to get all the thread's associated with the app domain, and walk their stacks... Look i agree its a dumb idea, but it's my boss's :-) — AK_, Nov 15 '10 at 11:54
@Hellfrost. You should try what you suggest, and post any code that you're having a problem with. — Matt Ellen, Nov 15 '10 at 12:02
@Matt Ellen. I will but i doubt Ill succeed... or even that its possible or wise. — AK_, Nov 15 '10 at 12:04

score 3 · Answer 1 · answered Nov 15 '10 at 11:13

3

This will search all the loaded assemblies.

AppDomain myDomain = AppDomain.CurrentDomain;
Assembly[] loadedAssemblies = MyDomain.GetAssemblies();
foreach(Assembly assembly in loadedAssemblies)
{
    Type[] types = assembly.GetTypes();
    foreach (Type type in types)
    {
        if (type.GetInterface(interface name) != null)
            Console.WriteLine(type.Name);
    }
}

answered Nov 15 '10 at 11:13

Itay Karo

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This is just finding the types, not the instances. He needs a IoC container of some sort. With that said, I did find your code useful :) – N_tro_P Mar 22 '16 at 13:55

Pieter van Ginkel · Accepted Answer · 2010-11-15T11:46:43.663

2

This cannot be done.

To find an object, you need a reference to it. If you do not have a reference to it, but want to "find" it, this is not possible.

edited Nov 15 '10 at 11:46

answered Nov 15 '10 at 11:10

Pieter van Ginkel

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1

he wants to find all objects. But your code returns class list. – acoolaum Nov 15 '10 at 11:18

score 1 · Answer 3 · answered Nov 15 '10 at 11:10

One way to do it would be to use MEF and it would probably perform better than using standard reflection.

http://mef.codeplex.com/

You basically add an attribute to all your interface implementations and MEF can then scan your assemblies (and any others in any folders you tell it to scan) for the implementations.

score 0 · Answer 4 · answered Nov 15 '10 at 11:58

So you want to find all instances that implement a specific interface - not the classes, the actual objects. You need to somehow enumerate over instances of objects. I am not aware of a way to do that.

If you could, however, create some sort of common ancestor for all the relevant objects that you have (something like your own Object class) then you can add a static enumeration of all the instances that were created by registering them in the constructor. You can then simply run over them and check each instance to see if it implements the interface. The problem with this approach is, of course, that these instances will never be garbage collected, even when you are done using them because they always have a reference pointing to them.

This leads me to the concolusion that there probably isn't a "built in" way to enumerate over instances of a class or interface, or even to enumerate over all the instances in the memory because having any such enumeration object means that these instances can never be garbage collected even when you no longer have a reference to them, because they can still be "referenced". This idea condradicts the whole point in managed code... So unless you find your own way to enumerate the instances, I don't think you will be able to do that.

hope that helps :-)

Getting all the object implementing an interface inside an application

4 Answers4