iterator - 如何实现与Angular Dart一起使用的迭代器

Question

我正在将Iterable功能添加到enyo的csvparser.dart的分支中，以便与Angular Dart一起使用。通过添加mixin，CsvParser可与for..in循环一起使用，但使ng-repeat失败，并带有“RangeError:value 0”。

我通过扩展Iterator和IterableMixin做错了，但是我被卡住了。

堆栈跟踪

RangeError: value 0

STACKTRACE:
#0      Iterator&IterableMixin.elementAt (dart:collection/iterable.dart:190)
#1      Scope.$watchCollection.<anonymous closure> (package:angular/core/scope.dart:397:60)
#2      relaxFnArgs2.<anonymous closure> (package:angular/utils.dart:49:47)
#3      Scope._digestHandleDirty (package:angular/core/scope.dart:613:24)
#4      Scope._digestComputeLastDirty (package:angular/core/scope.dart:564:36)
#5      Scope._digestWhileDirtyLoop (package:angular/core/scope.dart:489:52)
#6      Scope.$digest (package:angular/core/scope.dart:475:28)
#7      _autoDigestOnTurnDone (package:angular/core/scope.dart:153:14)
#8      _rootRun (dart:async/zone.dart:710)
#9      _ZoneDelegate.run (dart:async/zone.dart:440)
#10     NgZone._finishTurn (package:angular/core/zone.dart:91:21)
#11     NgZone._onRunBase (package:angular/core/zone.dart:56:43)
#12     _onRun (package:angular/core/zone.dart:61:15)
#13     _ZoneDelegate.run (dart:async/zone.dart:440)
#14     _CustomizedZone.run (dart:async/zone.dart:650)
#15     NgZone.run (package:angular/core/zone.dart:143:27)
#16     ngBootstrap (package:angular/bootstrap.dart:89:18)
#17     main (http://127.0.0.1:3030/staffing/web/main.dart:36:14)

csvparser.dart

class CsvParser extends Iterator with IterableMixin<CsvLineParser> {
  ...
  Iterator<CsvLineParser> get iterator => this;

主镖

    @NgController(
        selector: '[spreadsheet]',
        publishAs: 'ctrl')
    class SpreadsheetCtrl
    {
    //  "first_name","last_name","company_name","address","city","county","state","zip","phone1","phone2","email","web"

      String raw = '''
    "James","Butt","Benton, John B Jr","6649 N Blue Gum St","New Orleans","Orleans","LA",70116,"504-621-8927","504-845-1427","jbutt@gmail.com","http        ://www.bentonjohnbjr.com"
    "Josephine","Darakjy","Chanay, Jeffrey A Esq","4 B Blue Ridge Blvd","Brighton","Livingston","MI",48116,"810-292-9388","810-374-     9840","josephine_darakjy@darakjy.org","http://www.chanayjeffreyaesq.com"
    "Art","Venere","Chemel, James L Cpa","8 W Cerritos Ave #54","Bridgeport","Gloucester","NJ","08014","856-636-8749","856-264-4130","art@venere.       org","http://www.chemeljameslcpa.com"
    ''';
      CsvParser data;

      SpreadsheetCtrl()
      {
        data = new CsvParser(raw);
      }
    }

    class MyAppModule extends Module {
      MyAppModule() {
        type(SpreadsheetCtrl);
      }
    }

    void main() {
      ngBootstrap(module: new MyAppModule());
    }

index.html

    <div spreadsheet>
        <table>
          <tr ng-repeat="row in ctrl.data">
             <td ng-repeat="col in row">
              {{col}}
             </td>
          </tr>
        </table>
  ...
  <script type="application/dart" src="main.dart"></script>

测试 Dart

import 'web/csvparser.dart';

    main()
    {
      String raw = '''
    "first_name","last_name","company_name","address","city","county","state","zip","phone1","phone2","email","web"
    "James","Butt","Benton, John B Jr","6649 N Blue Gum St","New Orleans","Orleans","LA",70116,"504-621-8927","504-845-1427","jbutt@gmail.com","http://www.bentonjohnbjr.com"
    "Josephine","Darakjy","Chanay, Jeffrey A Esq","4 B Blue Ridge Blvd","Brighton","Livingston","MI",48116,"810-292-9388","810-374-9840","josephine_darakjy@darakjy.org","http://www.chanayjeffreyaesq.com"
    "Art","Venere","Chemel, James L Cpa","8 W Cerritos Ave #54","Bridgeport","Gloucester","NJ","08014","856-636-8749","856-264-4130","art@venere.org","http://www.chemeljameslcpa.com"
    ''';
      CsvParser data = new CsvParser(raw);
      for(var row in data)
      {
        for(var col in row)
        {
          print('${col}, ');
        }
      }
    }

Answer 1

如果集合和迭代器是同一类，这似乎不起作用(我不知道为什么)。

创建一个附加的CsvIterator类，并在CsvIterator的实现中返回CsvParser的实例，而不是this。

class CsvIterator extends Iterator<CsvLineParser> {
  CsvParser data;
  MyIterator(this.data);

  ... // implementation
}

class CsvParser extends Object with IterableMixin<CsvLineParser> {
  ...
  Iterator<CsvLineParser> get iterator => new CsvIterator(this);
}