如何在打字稿开关中正确使用枚举

Question

我在一个文件上有这个：

export module  Utils {
    export enum DataSources {
        SharepointList = "SharepointList",
        JsonData = "JsonData"
    };
}

在另一个文件上我有这个：

import CustomerDAO from "./ICustomerDAO";
import SharepointListDAOFactory from "./SharepointListDAOFactory";
import JsonDAOFactory from "./JsonDAOFactory";
import {Utils} from "./DatasourcesEnum";


export default abstract class DAOFactory{

    public static SHAREPOINTLIST: number = 1;
    public static REMOTEJSON : number = 2;

    public abstract getCustomerDAO(): CustomerDAO;

    public  static getDAOFactory(whichFactory: Utils.DataSources): DAOFactory {   
      switch (whichFactory) {
        case whichFactory.SharepointList: 
            return new SharepointListDAOFactory();
        case whichFactory.JsonData: 
            return new JsonDAOFactory();      
        default  : 
            return null;
      }
    }
}

但我收到这些错误：

Property 'SharepointList' does not exist on type 'DataSources'.

Answer 1

我不太确定你得到的错误是什么意思。不过，您似乎对枚举犯了一个错误。您在 switch 语句中使用分配的值而不是枚举本身。

public  static getDAOFactory(whichFactory: Utils.DataSources): DAOFactory {   
   switch (whichFactory) {
     case Utils.DataSources.SharepointList: 
       return new SharepointListDAOFactory();
     case Utils.DataSources.JsonData: 
       return new JsonDAOFactory();      
     default  : 
       return null;
   }
 }

whichFactory 标识符将具有一些反映在 Utils.DataSources 中的值，您希望将数据与枚举本身进行比较。该值本身不会包含其他数据源枚举。