#660 – The typeof Operator Gets Information About a Type

You can use the typeof operator to get information about a particular type.  The operator returns an instance of the Type class, which you can then query to get info about the type.

typeof is a little different from the GetType method in System.Object.  typeof gets type information for a type, whereas GetType gets type information for an object’s type.

        static void Main()
        {
            Dog kirby = new Dog("Kirby", 13);
            DumpTypeInfoFor(kirby.GetType());

            DumpTypeInfoFor(typeof(Dog));
        }

        private static void DumpTypeInfoFor(Type t)
        {
            Console.WriteLine("Type = {0}", t);
            // etc
        }

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#659 – Get Information About an Object’s Type

You can call the GetType method of System.Object on any object to get information about that object’s type.  Because every type in .NET inherits directly or indirectly from System.Object, every object will have access to the GetType method.

GetType returns an instance of a Type object, which can be queried to learn all about the type of the original object.

        static void Main()
        {
            Dog kirby = new Dog("Kirby", 13);
            DumpTypeInfoFor(kirby);

            int i = 12;
            DumpTypeInfoFor(i);
        }

        private static void DumpTypeInfoFor(object o)
        {
            Type t = o.GetType();

            Console.WriteLine("Type = {0}", t);
            Console.WriteLine("  Assembly = {0}", t.Assembly);
            Console.WriteLine("  BaseType = {0}", t.BaseType);
            Console.WriteLine("  FullName = {0}", t.FullName);
            Console.WriteLine("  IsClass = {0}", t.IsClass);
            Console.WriteLine("  IsValueType = {0}", t.IsValueType);

            Console.WriteLine("  Properties:");
            foreach (PropertyInfo pi in t.GetProperties())
                Console.WriteLine("    {0}", pi.Name);

            Console.WriteLine("  Methods:");
            foreach (MethodInfo mi in t.GetMethods())
                Console.WriteLine("    {0}", mi.Name);

            Console.WriteLine("  Events:");
            foreach (EventInfo ei in t.GetEvents())
                Console.WriteLine("    {0}", ei.Name);

            Console.WriteLine("  Interfaces:");
            foreach (Type ti in t.GetInterfaces())
                Console.WriteLine("    {0}", ti.Name);
        }