How do I create a generic class from a string in C#? [duplicate]

Question

I have a Generic class like that :

public class Repository<T> {...}

And I need to instance that with a string ... Example :

string _sample = "TypeRepository";
var _rep = new Repository<sample>();

How can I do that? Is that even possible?

Thanks!

Answer 1

Here is my 2 cents:

Type genericType = typeof(Repository<>);
Type[] typeArgs = { Type.GetType("TypeRepository") };
Type repositoryType = genericType.MakeGenericType(typeArgs);

object repository = Activator.CreateInstance(repositoryType);

Answering the question in comment.

MethodInfo genericMethod = repositoryType.GetMethod("GetMeSomething");
MethidInfo closedMethod = genericMethod.MakeGenericMethod(typeof(Something));
closedMethod.Invoke(repository, new[] { "Query String" });

Answer 2

First get the Type object using Type.GetType(stringContainingTheGenericTypeArgument)

Then use typeof(Repository<>).MakeGenericType(theTypeObject) to get a generic type.

And finally use Activator.CreateInstance

Answer 3

This is a job for the dynamic keyword coming in C# 4.0.

There are some nice hacks here that will get you an instance of your object, but no matter what the current version of C# will only know it has an object, and it can't do much with an object by itself because current C# does not support late binding. You need to be able to at least cast it to a known type to do anything with it. Ultimately, you must know the type you need at compile time or you're out of luck.

Now, if you can constrain your repository class to types implementing some known interface, you're in a much better shape.