如何在String中使用此名称获取属性? [英] How to get a property by this name in String?

问题描述

我想通过名称si字符串格式访问属性.

I want to access to a property by the name si string format.

如果我有这样的课程:

class PrefsState {
  String a;

  PrefsState({
    this.a,

  })

我该怎么做?

PrefsState test= PrefsState(a: "it is a test");
String key = "a";

print(test[key]);

当然不起作用.Dart有办法做到这一点吗?

Of course is not working. There is a way to do that in Dart ?

推荐答案

不幸的是，您不能在抖动中使用反射/镜像.您可以做的是乏味的，就是使用地图.

Unfortunately, you cannot use reflection/mirrors in flutter. What you can do, which is tedious, is use maps.

class PrefsState { 
   String a; 
   const PrefsState({ this.a, });
   dynamic getProp(String key) => <String, dynamic>{
    'a' : a,
    }[key];
}

在构造函数中构建映射可能更好，但是如果您要使用const构造函数，则必须为此解决.除非您有百万个参数，否则可能不会有太大的不同.然后像这样使用它:

It's probably better to build the map in the constructor, but if you want const constructors then you'll have to settle for this. Likely won't make much of a difference unless you have a million parameters anyway. Then you use it like so:

PrefsState test= PrefsState(a: "it is a test");
String key = "a"; 
print(test.getProp(key));

我认为没有比这麻烦的方法了，但是很想被证明是错误的:-)

I don't think there is a less cumbersome way of doing this, but would love to be proven wrong :-)

这篇关于如何在String中使用此名称获取属性?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！