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angular - 如何在课堂上将数字转换为枚举打字稿

问题描述

我有这门课

export class InstructorEvent {
EventID: number;
EvaluationMethod: number;

get EvalMethodEnum(): EvaluationMethodEnum {
    return 
EvaluationMethodEnum[EvaluationMethodEnum[this.EvaluationMethod]];
     }

 }


export enum EvaluationMethodEnum {
    None = -1,
    Test = 0,
    AssessmentForm = 1,
    PassFailDecision = 2,
    ParticipantSelfDeclaration = 3,
    ActivityAccess = 4,
    GradeDecision = 5,
    Courseware = 6,
    SCORM = 7,
    Attendance = 8,
    ObjectiveEvaluationManualGrade = 9,
    ObjectiveEvaluationPassFail = 10,
    ObjectiveEvaluationNone = 11,
    ObjectiveEvaluationCustom = 12,
    ObjectiveEvaluationAutoGrade = 14
}

现在我从服务器获取所有数据如下

this._service.getInstructorEvaluations(this.InstructorID).then(result => {
  if (result) {
    console.log(result);
    this.Events = result;

this.Events.forEach(element => {
  console.log(element.EvalMethodEnum);
    });
  }
});

'Events' 属性包含 InstructorEvent 对象的列表...

但它返回“未定义”，知道我做错了什么吗？

标签： angulartypescriptenumsangular6

解决方案

当您设置this.Events = result时，其中的项目this.Events不会被识别为 InstructorEvents，如果您只是强制转换它们，则内部的属性不会被初始化。您需要定义一个构造函数并显式创建 InstructorEvents。您的 EvalMethodEnum 函数中还有一个小错字。

这应该有效：

this.Events.forEach((element) => {
    element = new InstructorEvent(element.EventId, element.EvaluationMethod);
    console.log(element.EvalMethodEnum);
});

export class InstructorEvent {
    EventId: number;
    EvaluationMethod: number;

    constructor(eventId: number, evaluationMethod: number) {
        this.EventID = eventID;
        this.EvaluationMethod = evaluationMethod;
    }

    get EvalMethodEnum(): EvaluationMethodEnum {
        return EvaluationMethodEnum[this.EvaluationMethod];
    }
}

或者对于更简单的方法，您可以消除 EvalMethodEnum 调用并改为执行此操作：

this.Events.forEach((element: InstructorEvent) => {
    console.log(EvaluationMethodEnum[element.EvaluationMethod]);
});

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