从抽象类的静态方法返回类引用

Question

I understand that an abstract class can't be instantiated. Also, we can not use new keyword inside of a static method.

I'm wondering that how does the static Create method of XMLReader returns the reference of its class in the following statement:

XmlReader xmlReader=XmlReader.Create()

Thanks

Answer 1

It returns an instance of a derived class. It does not construct an XmlReader directly.

abstract class A {
    public static A Create() { return new B(); }
}
class B : A {
}

This is the same basic idea, and you can tell that that's what it does by calling GetType() on XmlReader.Create 's result. It won't return typeof(XmlReader) .