Is there a function to check if an object is a builtin data type?

Question

I would like to see if an object is a builtin data type in C#

I don\'t want to check against all of them if possible.
That is, I don\'t want to do this:

Answer 1

I think this is one of the best possibilies:

private static bool IsBulitinType(Type type)
{
    return (type == typeof(object) || Type.GetTypeCode(type) != TypeCode.Object);
}

Answer 2

Well, one easy way is to just explicitly list them in a set, e.g.

static readonly HashSet<Type> BuiltInTypes = new HashSet<Type>
    (typeof(object), typeof(string), typeof(int) ... };

...


if (BuiltInTypes.Contains(typeOfFoo))
{
    ...
}

I have to ask why it's important though - I can understand how it might make a difference if it's a .NET primitive type, but could you explain why you would want your application to behave differently if it's one of the ones for C# itself? Is this for a development tool?

Depending on the answer to that question, you might want to consider the situation with dynamic in C# 4 - which isn't a type at execution time as such, but is System.Object + an attribute when applied to a method parameter etc.

Answer 3

Not directly but you can do the following simplified check

public bool IsBulitin(object o) {
  var type = o.GetType();
  return (type.IsPrimitive && type != typeof(IntPtr) && type != typeof(UIntPtr))
        || type == typeof(string) 
        || type == typeof(object) 
        || type == typeof(Decimal);
}

The IsPrimitive check will catch everything but string, object and decimal.

EDIT

While this method works, I would prefer Jon's solution. The reason is simple, check the number of edits I had to make to my solution because of the types I forgot were or were not primitives. Easier to just list them all out explicitly in a set.