Typescript类AjaxBookStringParams方法BuildGenieParams调用报错求助

调用AjaxBookStringParams类的BuildGenieParams方法时，出现以下错误：

BookGenieLoader.ts:47 Uncaught TypeError: ajaxString.BuildGenieParams is not a function

这是该类唯一的方法，推测是低级错误导致无法运行。

相关代码 #

AjaxBookStringParams类代码 #

export class AjaxBookStringParams {
AgeCandidates: string = ""; // AllocationCandidates by age to-from server
BookToDelete:  string = ""; // Used to delete an allocated book
AllocatedBooks:  string = "";;; // placeholder for to-from server - grid display
BookGenieParams: string = "";
Data: string = "";
ProductFilterParams:  string = "";
Request: string = "";

constructor(ajaxParams:AjaxBookGenieParams){
    this.AgeCandidates = JSON.stringify(ajaxParams.AgeCandidates);
    this.BookToDelete = JSON.stringify(ajaxParams.AgeCandidates);
    this.AllocatedBooks = JSON.stringify(ajaxParams.AllocatedBooks);
    this.BookGenieParams = JSON.stringify(ajaxParams.BookGenieParams);
    this.ProductFilterParams = JSON.stringify(ajaxParams.ProductFilterParams);
    this.Data = ajaxParams.Data;
    this.Request = ajaxParams.Request;
}

BuildGenieParams():AjaxBookGenieParams{
    const ajaxBookGenieParams:AjaxBookGenieParams  = new  AjaxBookGenieParams();
    if(this.AgeCandidates != ""){ajaxBookGenieParams.AgeCandidates = JSON.parse(this.AgeCandidates)}
    if(this.BookToDelete != ""){ajaxBookGenieParams.BookToDelete = JSON.parse(this.BookToDelete)}
    if(this.AllocatedBooks != ""){ajaxBookGenieParams.AllocatedBooks = JSON.parse(this.AllocatedBooks)}
    if(this.BookGenieParams != ""){ajaxBookGenieParams.BookGenieParams = JSON.parse(this.BookGenieParams)}
    if(this.ProductFilterParams != ""){ajaxBookGenieParams.ProductFilterParams = JSON.parse(this.BookGenieParams)}  
    ajaxBookGenieParams.Data = this.Data;
    ajaxBookGenieParams.Request = this.Request;
    return ajaxBookGenieParams;
}

getJsonString():string{
    const jsonString = JSON.stringify({ajaxBookStringParams: AjaxBookStringParams,}) ;
    return jsonString;
}}

调用代码 #

$(function () {
  // this is param load from initial page load - only used once
let element = document.getElementById("AjaxBookGenieParamsHold");
let htmlElement: HTMLElement = element as HTMLElement;
let tParam: string = htmlElement.innerHTML;
let ajaxString:AjaxBookStringParams = JSON.parse (tParam);
let ajaxBookGenieParams:AjaxBookGenieParams = ajaxString.BuildGenieParams();
BookGenieMethods.ajaxBookGenieParams = ajaxBookGenieParams; // initial load of values
});

相关引用类（部分核心结构） #

export class AjaxBookGenieParams {
AgeCandidates: AgeCandidate[] = [];
BookToDelete: Book = new Book();
AllocatedBooks: AllocatedBook[] = [];
BookGenieParams: BookGenieParams = new BookGenieParams();
Data: string = "";
ProductFilterParams: ProductFilterParams = new ProductFilterParams();
Request: string = "";}

// 其他关联类（如Book、AgeCandidate等结构略）

错误原因 #

1. 核心问题：JSON解析结果不是类实例
   JSON.parse()返回的是普通JavaScript对象，而非AjaxBookStringParams类的实例。你通过TypeScript类型标注强制将其赋值给AjaxBookStringParams类型变量，但运行时该对象并不包含类定义的BuildGenieParams方法，因此调用时触发错误。

2. 次要代码错误

• 构造函数中this.BookToDelete = JSON.stringify(ajaxParams.AgeCandidates);赋值错误，应该使用ajaxParams.BookToDelete而非AgeCandidates
• BuildGenieParams方法中ajaxBookGenieParams.ProductFilterParams = JSON.parse(this.BookGenieParams)解析错误，应该解析this.ProductFilterParams而非BookGenieParams
• AllocatedBooks: string = "";;;存在多余分号

修复方案 #

1. 修正实例化逻辑 #

将JSON解析后的普通对象传入AjaxBookStringParams构造函数，创建真正的类实例：

$(function () {
  // 页面初始加载参数，仅使用一次
  let element = document.getElementById("AjaxBookGenieParamsHold");
  let htmlElement: HTMLElement = element as HTMLElement;
  let tParam: string = htmlElement.innerHTML;
  // 先解析为普通对象，再通过构造函数生成类实例
  let parsedParams = JSON.parse(tParam);
  let ajaxString:AjaxBookStringParams = new AjaxBookStringParams(parsedParams);
  let ajaxBookGenieParams:AjaxBookGenieParams = ajaxString.BuildGenieParams();
  BookGenieMethods.ajaxBookGenieParams = ajaxBookGenieParams; // 初始化参数
});

2. 修正代码中的低级错误 #

• 修正构造函数赋值：

constructor(ajaxParams:AjaxBookGenieParams){
    this.AgeCandidates = JSON.stringify(ajaxParams.AgeCandidates);
    this.BookToDelete = JSON.stringify(ajaxParams.BookToDelete); // 改为BookToDelete
    this.AllocatedBooks = JSON.stringify(ajaxParams.AllocatedBooks);
    this.BookGenieParams = JSON.stringify(ajaxParams.BookGenieParams);
    this.ProductFilterParams = JSON.stringify(ajaxParams.ProductFilterParams);
    this.Data = ajaxParams.Data;
    this.Request = ajaxParams.Request;
}

• 修正BuildGenieParams方法解析逻辑：

BuildGenieParams():AjaxBookGenieParams{
    const ajaxBookGenieParams:AjaxBookGenieParams  = new  AjaxBookGenieParams();
    if(this.AgeCandidates != ""){ajaxBookGenieParams.AgeCandidates = JSON.parse(this.AgeCandidates)}
    if(this.BookToDelete != ""){ajaxBookGenieParams.BookToDelete = JSON.parse(this.BookToDelete)}
    if(this.AllocatedBooks != ""){ajaxBookGenieParams.AllocatedBooks = JSON.parse(this.AllocatedBooks)}
    if(this.BookGenieParams != ""){ajaxBookGenieParams.BookGenieParams = JSON.parse(this.BookGenieParams)}
    if(this.ProductFilterParams != ""){ajaxBookGenieParams.ProductFilterParams = JSON.parse(this.ProductFilterParams)}  // 改为ProductFilterParams
    ajaxBookGenieParams.Data = this.Data;
    ajaxBookGenieParams.Request = this.Request;
    return ajaxBookGenieParams;
}

• 修正多余分号：AllocatedBooks: string = "";

3. 可选优化：添加静态fromJSON方法 #

为了简化实例化流程，可以在AjaxBookStringParams类中添加静态方法：

export class AjaxBookStringParams {
    // ... 现有属性和方法 ...

    static fromJSON(jsonStr: string): AjaxBookStringParams {
        const parsed = JSON.parse(jsonStr);
        return new AjaxBookStringParams(parsed);
    }
}

调用时可简化为：

let ajaxString = AjaxBookStringParams.fromJSON(tParam);

内容的提问来源于stack exchange，提问作者BedfordNYGuy