How to create instance w/ generic types w/ Activator.CreateInstance?

[dCyphr]

I have a class that has a generic type and I'm trying to create an instance using the activator but having trouble with it. This is what I have:

public abstract class MyBaseClass<T> where T : new()
{
...
public abstract T DoSomething();
}

public class MyClass<T> : MyBaseClass<T> where T : new()
{
...
public override T DoSomething() { .. }
}

And this is what I'm trying to do but didn't work. This gives my a null error: System.ArgumentNullException: Value cannot be null:

string someStr = "MyClass";
MyBaseClass<Customer> customerProvider =
Activator.CreateInstance(Type.GetType(someStr));



I also tried this but didn't work. It gave a compiler error about Activator.CreateInstance can't find that overloaded method. :

string someStr = "MyClass";
MyBaseClass<Customer> customerProvider =
Activator.CreateInstance<Customer>(Type.GetType(someStr));

Any other ideas on how to pass <Customer> to the Activator? There's gotta be some kind of syntax for it but couldn't find it anywhere.

 

[dCyphr]

Just to add to my original post, I even tried hardcoding everything like this and still gave me a null exception:

MyBaseClass<Customer> customerProvider =
Activator.CreateInstance("MyClass<Customer>");

And just to make sure I wasn't doing anything stupid somewhere, doing this worked fine:
MyBaseClass<Customer> customerProvider = new MyClass<Customer>();

Any idea on how to achieve this?

 

[misterstick]

http://www.google.com/search?hl=en&q=Activator.CreateInstance+generics

#2

http://msdn2.microsoft.com/en-us/library/b8ytshk6.aspx#sectionToggle0

hth,


mr s. <

 

[dCyphr]

I got it! Phew did I have to dig.

It has very weird syntax with a backtick and brackets. Initially I tried following the MSDN guide on GetType (two-thirds down the page:

http://msdn2.microsoft.com/en-us/library/w3f99sx1.aspx)

which told me to do the following but still came up with a null:
Type constructedType = Type.GetType("MyClass`1[Customer]");

So in the end, this finally worked for me:
Type classType = Type.GetType("MyClass`1");
Type[] typeParams = new Type[] { typeof(Customer) };
Type constructedType = classType.MakeGenericType(typeParams);

MyBaseClass<Customer> customerProvider =
Activator.CreateInstance(constructedType) as MyBaseClass<Customer>;

I didn't realize the null was happening at GetType.. the whole time I thought the problem was with Activator.CreateInstance.