Question 353709 in Flutter Question posted in
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Flutter – Switch enum on attributes in dart

I am having this enum:

enum ContentError {
  e410('Exception: 410'),
  e411('Excetion: 411'),
  e412('Exception: 412'),
  e413('Exception: 413');

  const ContentError(this.name);

  final String name;
}

Now I get some String and I want to do a switch case on the names of the Enum.

switch (myString) {
  case ContentError.e410.name:
    // do something
  ...
}

but this does not work as it says The property 'name' can't be accessed on the type 'ContentError' in a constant expression.

How can I do a switch case on the Enum attriute name?

Tags:

2

Answers


  1. 0

    Try this!

    enum ContentError {
  e410,
  e411,
  e412,
  e413,
}

extension ContentErrorExtension on ContentError {
  String get name {
    switch (this) {
      case ContentError.e410:
        return 'Exception: 410';
      case ContentError.e411:
        return 'Exception: 411';
      case ContentError.e412:
        return 'Exception: 412';
      case ContentError.e413:
        return 'Exception: 413';
      default:
        return '';
    }
  }
}

void main() {
  String myString = 'Exception: 410';

  switch (myString) {
    case ContentError.e410.name:
      print('Handling Exception 410');
      break;
    case ContentError.e411.name:
      print('Handling Exception 411');
      break;
    case ContentError.e412.name:
      print('Handling Exception 412');
      break;
    case ContentError.e413.name:
      print('Handling Exception 413');
      break;
    default:
      print('Unhandled exception');
  }
}
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  2. 0

    You can change the switch case and define the action each case using map and returning the method to execute correct conditions, the step explained in the code below:

    // your input
final myString = ContentError.e410.name;

// define the action rule, like switch case
final rule = {
  ContentError.e410.name: () {
    print('do something e410');
  },
  ContentError.e411.name: () {
    print('do something e411');
  },
  ContentError.e412.name: () {
    print('do something e412');
  },
  ContentError.e413.name: () {
    print('do something e413');
  },
}[myString];

// default action, act like default 
// in the switch case
final def = () {
  print('default');
};

// execute the rule result
// if rule not contains the input
// then call default action
(rule ?? def)();

    And this is the results:

    enter image description here

    enter image description here

    enter image description here

    enter image description here

    Hopefully it can solve your problem, Thanks 😉

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