Dart中的Dynamic和Object之间有什么区别?

问题描述

它们似乎都可以在相同的情况下使用.在类型检查等方面有不同的表示形式或不同的细微之处吗?

They both seem like they can be used in identical cases. Is there a different representation or different subtleties in type checking, etc?

推荐答案

动态类型部分/ECMA-ST/ECMA-408.pdf"rel =" noreferrer> Dart编程语言规范，第三版指出:

The section Type dynamic from the Dart Programming Language Specification, 3rd Edition states :

这意味着通过在dynamic类型变量上调用任何方法都不会收到警告.对于类型为Object的变量，情况并非如此.例如:

That means you will not get warnings by calling any method on a dynamic typed variable. That will not be the case with a variable typed as Object. For instance:

dynamic a;
Object b;

main() {
  a = "";
  b = "";
  printLengths();
}

printLengths() {
  // no warning
  print(a.length);

  // warning:
  // The getter 'length' is not defined for the class 'Object'
  print(b.length);
}

在运行时，我认为您应该不会有任何区别.

At runtime, I think, you shouldn't see any difference.

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