使用泛型，您可以

var object = default(T);

但是，当你已经是一个类型的实例我只能

But when all you have is a Type instance I could only

constructor = type.GetConstructor(Type.EmptyTypes);
var parameters = new object[0];
var obj = constructor.Invoke(parameters);

甚至

var obj = type.GetConstructor(Type.EmptyTypes).Invoke(new object[0]);

还没有一个较短的方式，像仿制药版本？

Isn't there a shorter way, like the generics version?

推荐答案

最近的可用的Activator.CreateInstance:

The closest available is Activator.CreateInstance:

object o = Activator.CreateInstance(type);

...但当然，这依赖于那里是一个公共参数的构造函数。 （其他重载允许您指定构造函数的参数。）

... but of course this relies on there being a public parameterless constructor. (Other overloads allow you to specify constructor arguments.)

我用显式类型变量在这里说清楚，我们真的没有该类型本身的变量...你不能写：

I've used an explicitly typed variable here to make it clear that we really don't have a variable of the type itself... you can't write:

Type t = typeof(MemoryStream);
// Won't compile
MemoryStream ms = Activator.CreateInstance(t);

例如。返回值的CreateInstance 的编译时类型总是对象。

for example. The compile-time type of the return value of CreateInstance is always object.

注意默认（T）的不会的创建一个引用类型的实例 - 它给出了类型，默认值是引用类型空引用。相比之下，与的CreateInstance 这实际上将创建一个新的对象。

Note that default(T) won't create an instance of a reference type - it gives the default value for the type, which is a null reference for reference types. Compare that with CreateInstance which would actually create a new object.