Deciding on type in the runtime and applying it in generic type - how can I do this ?

Question

I would like to create a strongly type list and decide the type in runtime. This is my code.I thought it should work, but it doesn't :)

        Type elementType = Type.GetType(parts[0].Trim(),false,true);
        var elementsBeingSet = new List<elementType>();

would you have any ideat how to create a strongly typed list whose type I will decide in runtime ?

Duplicate: here are other versions:

• http://stackoverflow.com/questions/234008/is-it-impossible-to-use-generics-dynamically
• http://stackoverflow.com/questions/307984/declare-a-generic-type-instance-dynamically
• http://stackoverflow.com/questions/325156/calling-generic-method-with-a-type-argument-known-only-at-execution-time

Answer 1

Use Type.MakeGenericType(type[]):

Type elementType = GetElementType(); // get this type at runtime
Type listType = typeof(List<>);
Type combinedType = listType.MakeGenericType(elementType);
IList elements = (IList) Activator.CreateInstance(combinedType);

You have to use IList to keep the result - because you don't know the actual type that will be used at runtime.

For generic types with more than one type parameter you would use something like Dictionary<,>.

See also http://msdn.microsoft.com/en-us/library/system.type.makegenerictype.aspx