Generic Factory Example

GenericFactoryPatternExample.cs

using System;
using System.Collections.Generic;

namespace GenericFactoryPatternExample
{
    public class MainClass
    {
        // Example of using a service locator to get the correct factory for 
        // a given object type. 
        public static void Main()
        {
            var factoryA = ServiceLocator.GetFactoryFor<AlphaClass>();
            var alphaObject = factoryA.Create(); // object is now strong typed
            System.Diagnostics.Debug.WriteLine("Description: " + alphaObject.Description);
            
            var factoryB = ServiceLocator.GetFactoryFor<BravoClass>();
            var bravoObject = factoryB.Create();
            System.Diagnostics.Debug.WriteLine("Name: " + bravoObject.Name); 
        }
    }

    public class ServiceLocator
    {
        public static FactoryBase<T> GetFactoryFor<T>() // The "Service Locator" method
        {
            if (typeof(T) == typeof(AlphaClass)) return (FactoryBase<T>)((object)new AlphaFactory());
            if (typeof(T) == typeof(BravoClass)) return (FactoryBase<T>)((object)new BravoFactory());
            throw new ArgumentException("No factory defined for type " + typeof(T));
        }
    }

    public class FactoryBase<T>
    {
        internal virtual T Create() { return default(T); }
    }

    class AlphaFactory : FactoryBase<AlphaClass> 
    {
        internal override AlphaClass Create()
        {
            return new AlphaClass { Description = "Hello world" };
        }
    }

    class BravoFactory : FactoryBase<BravoClass>
    {
        internal override BravoClass Create()
        {
            return new BravoClass { Name = "Check this out" };
        }
    }

    class AlphaClass
    {
        internal string Description { get; set; }
    }

    class BravoClass
    {
        internal string Name { get; set; }
    }
}