TypeScript类函数不可用 [英] TypeScript class function not available

问题描述

我正在尝试调用TypeScript类的实例方法（在ASP.NET MVC项目中）。但是，在运行时我得到的异常如 0x800a01b6 - JavaScript运行时错误：对象不支持属性或方法'checkString'。

I'm trying to call a instance method of a TypeScript class (in an ASP.NET MVC project). However, at Runtime I get exceptions like 0x800a01b6 - JavaScript runtime error: Object doesn't support property or method 'checkString'.

我将生成的JavaScript复制到 jsfiddle 这个方法似乎有用。

我不是一个真正的JavaScript人，所以非常感谢任何帮助！

I copied the generated JavaScript in a jsfiddle where the method seems to work.
I'm not really a JavaScript guy, so any help is much appreciated!

东西到目前为止我已尝试过：

1. 不同的浏览器（Chrome：未捕获TypeError：undefined不是function ，FF： TypeError：this.checkString不是函数）


2. 清除浏览器缓存


3. 删除IIS Express的临时文件


4. 清理并重建解决方案


5. 不使用私有修饰符


6. 在另一台机器上启动项目


7. 用假人替换underscore.js调用以验证这不是问题


8. 检查实例成员是否已正确设置

1. different browsers (Chrome: Uncaught TypeError: undefined is not a function, FF: TypeError: this.checkString is not a function)
2. clearing browser caches
3. deleting the temporary files of IIS Express
4. cleaning and rebuilding the solution
5. not using the private modifier
6. starting the project on another machine
7. replacing the underscore.js call with a dummy to verfiy that's not the problem
8. checked that the instance members are correctly set

这是TypeScript代码：

class FormData {
    BlogName: string;
    CacheTimeOut: number;
    CopyrightHolder: string;
    NavBarTitle: string;
    MarkdownExtra: boolean;
    MarkdownSanitize: boolean;
    RatingActive: boolean;
    HtmlEditor: boolean;

    constructor(blogName: string, cacheTimeOut: number, copyrightHolder: string, navBarTitle: string, markdownExtra: boolean, markdownSanitize: boolean, ratingActive: boolean, htmlEditor: boolean) {
        this.BlogName = blogName;
        this.CacheTimeOut = cacheTimeOut;
        this.CopyrightHolder = copyrightHolder;
        this.NavBarTitle = navBarTitle;
        this.MarkdownExtra = markdownExtra;
        this.MarkdownSanitize = markdownSanitize;
        this.RatingActive = ratingActive;
        this.HtmlEditor = htmlEditor;
    }

    private checkString(value: string): boolean {
        return _.isString(value) && value !== '';
    }

    validate(): boolean {
        return (this.checkString(this.BlogName) && this.checkString(this.CopyrightHolder) && this.checkString(this.NavBarTitle) && _.isNumber(this.CacheTimeOut) && !_.isNull(this.MarkdownExtra) && !_.isNull(this.MarkdownSanitize) && !_.isNull(this.RatingActive));
    }       
}

//I'm calling the validate function like that (from within the same module)
var form = getFormData(); //returns a FormData instance
if (!form.validate()) {
    //foo
}

这里生成的JavaScript：

var FormData = (function () {
    function FormData(blogName, cacheTimeOut, copyrightHolder, navBarTitle, markdownExtra, markdownSanitize, ratingActive, htmlEditor) {
        this.BlogName = blogName;
        this.CacheTimeOut = cacheTimeOut;
        this.CopyrightHolder = copyrightHolder;
        this.NavBarTitle = navBarTitle;
        this.MarkdownExtra = markdownExtra;
        this.MarkdownSanitize = markdownSanitize;
        this.RatingActive = ratingActive;
        this.HtmlEditor = htmlEditor;
    }
    FormData.prototype.checkString = function (value) {
        return _.isString(value) && value !== '';
    };

    FormData.prototype.validate = function () {
        return (this.checkString(this.BlogName) && this.checkString(this.CopyrightHolder) && this.checkString(this.NavBarTitle) && _.isNumber(this.CacheTimeOut) && !_.isNull(this.MarkdownExtra) && !_.isNull(this.MarkdownSanitize) && !_.isNull(this.RatingActive));
    };
    return FormData;
})();

推荐答案

这可能是因为错误的这个在运行时。您可以使用lambda函数（）=> {} 而不是函数来确保此在生成的JavaScript中具有词法范围：

This is probably because of the wrong this at runtime. You can use a lambda function ()=>{} instead of function to make sure that the this is lexically scoped in the generated JavaScript:

validate = (): boolean => {
        return (this.checkString(this.BlogName) && this.checkString(this.CopyrightHolder) && this.checkString(this.NavBarTitle) && _.isNumber(this.CacheTimeOut) && !_.isNull(this.MarkdownExtra) && !_.isNull(this.MarkdownSanitize) && !_.isNull(this.RatingActive));
    } 

请搜索此在javascript和typescript中表示了解更多信息。

Please search for what this means in javascript and typescript to learn more.

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