在Dart中动态设置变量名称 [英] Dynamically setting variable name in Dart

问题描述

我已经在Dart中将变量名称和值保存到JSON文件中.后来，我从该JSON文件中提取了名称和值，现在尝试使用该名称创建一个新变量.像这样:

I had saved a variables name and value to a JSON file in Dart. Later I extracted the name and value from that JSON file and now am trying to create a new variable with that name. Something like this:

var variableName= "firstName";
String variableName = "Joe";

这样:

String firstName = "Joe";

有没有办法做到这一点?

Is there a way to do this?

推荐答案

简短答案:否.

您无法在Dart中在运行时创建变量.编译器假定在编译程序(或任何单个方法)时所有变量都是可见的.

You cannot create variables at runtime in Dart. The compiler assumes that all variables are visible when the program (or any single method) is compiled.

在Dart中查找变量的方式是，如果词法范围中存在这样的变量，则"x"是指局部，静态或顶级变量，如果存在，则它是指"this.x"在名为"x"的词法范围内是变量.

The way variables are looked up in Dart is that "x" refers to a local, static or top-level variable, if there is such a variable in the lexical scope, and it refers to "this.x" if there is variable in the lexical scope named "x".

如果以后可以添加变量，则可以将"x"从含义"this.x"更改为其他含义.这样，已经编译的代码将不正确.

If you could add a variable later, you would be able to change "x" from meaning "this.x" to meaning something else. Already compiled code would then be incorrect.

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