TypeScript的字符串枚举

本文介绍了TypeScript的字符串枚举-“类型...不可分配给类型..."的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我最近将TypeScript的版本从2.3.4升级到了2.4.0，希望使用字符串枚举.但是令我沮丧的是，我收到了以下错误消息:

I have recently upgraded the version of TypeScript from 2.3.4 to 2.4.0 hoping to use the string enums. To my dismay, however, I have been greeted with the error messages:

Severity Code Description Project File Line Suppression State Error TS2322 Type '"E"' is not assignable to type 'StepType'. ClientApp (tsconfig project) Z:\SMART\Smart\Smart\ClientApp\app\models\process.model.ts 17 Active Error TS2322 Type '"S"' is not assignable to type 'StepType'. ClientApp (tsconfig project) Z:\SMART\Smart\Smart\ClientApp\app\models\process.model.ts 14 Active Error TS2322 Type '"A"' is not assignable to type 'StepType'. ClientApp (tsconfig project) Z:\SMART\Smart\Smart\ClientApp\app\models\process.model.ts 15 Active Error TS2322 Type '"D"' is not assignable to type 'StepType'. ClientApp (tsconfig project) Z:\SMART\Smart\Smart\ClientApp\app\models\process.model.ts 16 Active

错误消息适用于以下代码段(带有行号):

The error messages apply to the following code snippet (with the line numbers):

13. export enum StepType { 14. Start = 'S', 15. Activity = 'A', 16. Decision = 'D', 17. End = 'E' 18. }

我正在使用Visual Studio 2017，它声称已安装TypeScript 2.4.0:

I am using Visual Studio 2017 which claims TypeScript 2.4.0 is installed:

我搜索了

解决此问题的方法是下载并安装 TypeScript 2.4 SDK ，然后从选项中选择较新的版本:

The way to resolve the issue was to download and install TypeScript 2.4 SDK and then select from the options the newer version: