对于
public static Object CreateInstance (
Type type
)
Type type
)
方法我想您应该用过，当您需要动态的创建某些类型实例的时候您就需要它了。但是我今天测试该方法和用Expression Tree方法实例化对象的哪个执行的效率更快的时候，我发现一个问题。我把问题代码抽出来，做几个实验，您看看：（该实验在vs2008和vs2005下面都做了，实验结果一样，具体数值是vs2005下面的，以下代码均是在Release模式下）
1 Stopwatch watch1 = new Stopwatch();
2 watch1.Start();
3 Class1 formActivator1 = Activator.CreateInstance(typeof(Class1)) as Class1;
4 watch1.Stop();
5 Console.WriteLine("Activator CreateInstance");
6 Console.WriteLine(watch1.Elapsed.ToString());
7
2 watch1.Start();
3 Class1 formActivator1 = Activator.CreateInstance(typeof(Class1)) as Class1;
4 watch1.Stop();
5 Console.WriteLine("Activator CreateInstance");
6 Console.WriteLine(watch1.Elapsed.ToString());
7
得出的记过为：
Activator CreateInstance
00:00:00.0001561
00:00:00.0001561
我在前面加上如下代码：
Class1 c1 = new Class1();
再执行，我们看看结果：
Activator CreateInstance
00:00:00.0000203
00:00:00.0000203
您看到区别了吗？没有Class1 c1 = new Class1();的时候执行时间是有Class1 c1 = new Class1();执行时间的将近8倍。那么我们再看下面的代码：
1 Class1 c1 = new Class1();
2
3 Stopwatch watch1 = new Stopwatch();
4 watch1.Start();
5 Class1 formActivator1 = Activator.CreateInstance(typeof(Class1)) as Class1;
6 watch1.Stop();
7 Console.WriteLine("Activator CreateInstance");
8 Console.WriteLine(watch1.Elapsed.ToString());
9
10 Stopwatch watch2 = new Stopwatch();
11 watch2.Start();
12 Class1 formActivator2 = Activator.CreateInstance(typeof(Class1)) as Class1;
13 watch2.Stop();
14 Console.WriteLine("Activator CreateInstance");
15 Console.WriteLine(watch2.Elapsed.ToString());
2
3 Stopwatch watch1 = new Stopwatch();
4 watch1.Start();
5 Class1 formActivator1 = Activator.CreateInstance(typeof(Class1)) as Class1;
6 watch1.Stop();
7 Console.WriteLine("Activator CreateInstance");
8 Console.WriteLine(watch1.Elapsed.ToString());
9
10 Stopwatch watch2 = new Stopwatch();
11 watch2.Start();
12 Class1 formActivator2 = Activator.CreateInstance(typeof(Class1)) as Class1;
13 watch2.Stop();
14 Console.WriteLine("Activator CreateInstance");
15 Console.WriteLine(watch2.Elapsed.ToString());