Here is a little test code that demonstrates how to use Generics at runtime. The code has two tests. The first test shows how to create a Generic Class at runtime. The second shows how to call a Generic method. Keep in mind that when using generics at runtime, there will be a reflection performance hit.
using System;
using System.Collections.ObjectModel;
using Microsoft.VisualStudio.QualityTools.UnitTesting.Framework;
using System.Reflection;
using System.Diagnostics;
namespace GenericTest
{
[TestClass]
public class GenericTest
{
[TestMethod]
public void CreateGenericAtRuntime()
{
Stopwatch watch = Stopwatch.StartNew();
// define the generic class at runtime
Type genericType = typeof(Collection<>).MakeGenericType(typeof(DateTime));
// create an instance of the generic type
object instance = Activator.CreateInstance(genericType);
watch.Stop();
Console.WriteLine("Dynamic Create Time: {0} ms", watch.Elapsed.TotalMilliseconds);
Assert.IsNotNull(instance, "instance is Null");
Assert.IsTrue(instance is Collection<DateTime>);
Collection<DateTime> dates = instance as Collection<DateTime>;
Assert.IsNotNull(dates, "dates is Null");
watch = Stopwatch.StartNew();
Collection<DateTime> d = new Collection<DateTime>();
watch.Stop();
Console.WriteLine("Normal Create Time: {0} ms", watch.Elapsed.TotalMilliseconds);
}
public Collection<T> GetCollection<T>()
{
return new Collection<T>();
}
[TestMethod()]
public void CallGenericMethodAtRuntime()
{
Stopwatch watch = Stopwatch.StartNew();
MethodInfo methodInfo = typeof(GenericTest).GetMethod("GetCollection");
MethodInfo genericInfo = methodInfo.MakeGenericMethod(typeof(DateTime));
object instance = genericInfo.Invoke(this, null);
watch.Stop();
Console.WriteLine("Dynamic Invoke Time: {0} ms", watch.Elapsed.TotalMilliseconds);
Assert.IsNotNull(instance, "instance is Null");
Assert.IsTrue(instance is Collection<DateTime>);
Collection<DateTime> dates = instance as Collection<DateTime>;
Assert.IsNotNull(dates, "dates is Null");
watch = Stopwatch.StartNew();
Collection<DateTime> d = this.GetCollection<DateTime>();
watch.Stop();
Console.WriteLine("Normal Invoke Time: {0} ms", watch.Elapsed.TotalMilliseconds);
}
}
}