Passed an instantiated System.Type as a Type Parameter for a Generic method

Question

I have this code snippet that I want to simplify:

        switch (typeString)
        {
            case "boolean":
                CreateSimpleRows<bool>(ref group, value);
                break;
            case "datetime":
                CreateSimpleRows<DateTime>(ref group, value);
                break;
            case "double":
                CreateSimpleRows<double>(ref group, value);
                break;
            case "int32":
                CreateSimpleRows<int>(ref group, value);
                break;
            case "int64":
                CreateSimpleRows<long>(ref group, value);
                break;
            case "string":
                CreateSimpleRows<string>(ref group, value);
                break;
        }

The method is declared as CreateSimpleRows<T>. I tried passing a System.Type instance, but that didn't work.

I came across this answer to a similar question: http://stackoverflow.com/questions/266115/pass-an-instantiated-system-type-as-a-type-parameter-for-a-generic-class/266282#266282

I've checked and I've seen that there's a MakeGenericMethod in the MethodInfo class. Thing is, I don't know how to convert "CreateSimpleRows" into a MethodInfo instance.

Is what I'm thinking of achieving even possible? Thanks in advance for the replies.

Answer 1

To get a MethodInfo, you call Type.GetMethod:

MethodInfo method = typeof(TypeContainingMethod).GetMethod("CreateSimpleRows");
MethodInfo generic = method.MakeGenericMethod(typeArgument);

Note that if you want to get a non-public method you'll need to use the overload of GetMethod which takes a BindingFlags as well.

It's not really clear why you want to do this with reflection though. While your current snippet is repetitive, it's at least simple to understand. Using reflection is likely to make things more error-prone, and you'd still have to map typeString to a Type to start with.