使用.Net,如何确定类型是否为数值ValueType？

using System;

public class Program
{
    public static void Main()
    {
        Type intType = typeof(int);
        Type stringType = typeof(string);

        Console.WriteLine("int is a value type: " + intType.IsValueType);
        Console.WriteLine("string is a value type: " + stringType.IsValueType);
    }
}

int is a value type: True
string is a value type: False