Why I cannot use Type.GetType() in generics?

Question

I am trying to get rid of some references by using string representation of certain types. But compiler is not letting me do it the way I want in case of generic methods. I

Answer 1

You can use Type.MakeGenericType. Example:

Type.GetType("YourGenericType").MakeGenericType(Type.GetType("yourTypeParameter"))

Example for a List with a typeparameter determined from a string:

typeof(List<>).MakeGenericType(Type.GetType("System.String"))

This gives you the same as

typeof(List<string>)

But you still can't use a Type instance to call Enumerable.OfType. You could use something like this instead:

foreach (var component in container.Components.Where(o => o.GetType().IsAssignableFrom(yourType))) 
{
    //...
}

Of course, this get's messy quickly, so I would consider changing your approach. Why do you wan't to use strings?

Answer 2

You want this:

foreach (var component in container.Components.OfType<MyNamespace.MyType>()) {
...
}

Problem is you have to use the actual type expression in generics, not a string. You could construct the type using reflection if you really need to use the string.

Answer 3

You can't use a variable in the place of the generic type argument (between < and >). It has to be a type determined at compile time.

But in your example this is already the case. Can't you just use

foreach (var component in container.Components.OfType<MyNamespace.MyType>()) {
...
}