javascript - 如何使用 Dart 在 Angular 2 中创建动态组件？

Question

我想动态切换 Angular 2/Dart 组件使用的 templateUrl。

我发现解决方法是动态创建一个新组件来放置 templateUrl。有几个示例说明如何使用 Angular 2 ComponentResolver 和 TypeScript 来实现此目的，for example this one ，但我一直未能将它们转换为 Dart。

基本上我失败的是从函数传递一个新组件:

createComponentFactory(ComponentResolver resolver,
        ComponentMetadata metadata) {
    final cmpClass = class DynamicComponent {};
    final decoratedCmp = Component(metadata)(cmpClass);
    return resolver.resolveComponent(decoratedCmp);
}

此方法以及 Dart 的其他类似方法的问题在于，我无法将 class DynamicComponent {}; 设置为变量或从函数返回它，而不会出现如下构建错误:

[DirectiveProcessor]:
  Failed with 5 errors
Error 1: line 37, column 22 of lib/projects/project_component.dart and parts: Expected an identifier
    final cmpClass = class DynamicComponent {};
                     ^^^^^
Error 2: line 37, column 22 of lib/projects/project_component.dart and parts: Expected to find ';'
    final cmpClass = class DynamicComponent {};
                     ^^^^^
Error 3: line 37, column 22 of lib/projects/project_component.dart and parts: Expected a statement
    final cmpClass = class DynamicComponent {};
                     ^^^^^
Error 4: line 37, column 22 of lib/projects/project_component.dart and parts: Unexpected token 'class'
    final cmpClass = class DynamicComponent {};
                     ^^^^^
Error 5: line 37, column 28 of lib/projects/project_component.dart and parts: Expected to find ';'
    final cmpClass = class DynamicComponent {};
                           ^^^^^^^^^^^^^^^^

在遵循我见过的创建动态组件的任何示例时，创建这样的新组件是我常见的障碍。有谁知道如何使用 Dart 实现这一目标吗？

Answer 1

您无法在 Dart 中声明内联类。

这应该可以达到你想要的效果

class DynamicComponent {}

createComponentFactory(ComponentResolver resolver,
        ComponentMetadata metadata) {
    final cmpClass = DynamicComponent;
    final decoratedCmp = Component(metadata)(cmpClass);
    return resolver.resolveComponent(decoratedCmp);
}

如果您能让它发挥作用，我会很高兴看到完整的解决方案。