在脚本类型数组 [英] Arrays in type script

问题描述

我发现很难在声明数组打字稿和访问它。

I am finding difficulty declaring array in typescript and accessing it.

下面是code为我工作

below is the code working for me

------------------------------------------------------
 class Book {
    public BookId: number;
    public Title: string;
    public Author: string;
    public Price: number;
    public Description: string;
}
class dataservice {
      getproducts() {
         var bk = new Book();
        bk.Author = "vamsee";
        bk.BookId = 1;
        var bks: Book[] = [bk,bk];

      return bks.length;
    }
}

var ds = new dataservice();
var button = document.createElement('button');

button.onclick = function () {

    alert(ds.getproducts().toString());
}

document.body.appendChild(button);
--------------------------------------------------------------

当我改变我的code如下试图值分配给数组项时失败。

when i change my code as below it fails when trying to assign value to array item.

 var bks: Book[] = new Book[2];
bks[0].Author = "vamsee";
        bks[0].BookId = 1;
      return bks.length;

我在循环中添加对象，我必须这样做，第二种方式。

for me to add object in a loop i have to do it the second way.

请建议....感谢

推荐答案

这是一个非常C $ C $的C＃类型：

This is a very c# type of code:

var bks: Book[] = new Book[2];

在使用Javascript /打字稿你不分配内存，前面那样，这意味着完全不同的东西。这是你会怎么做你想做的事：

In Javascript / Typescript you don't allocate memory up front like that, and that means something completely different. This is how you would do what you want to do:

var bks: Book[] = [];
bks.push(new Book());
bks[0].Author = "vamsee";
bks[0].BookId = 1;
return bks.length;

现在解释什么新集[2]; 意味着什么。这实际上意味着，调用新的运算符书[2]的数值。例如：

Now to explain what new Book[2]; would mean. This would actually mean that call the new operator on the value of Book[2]. e.g.:

Book[2] = function (){alert("hey");}
var foo = new Book[2]

，你应该看到哎。 <一href=\"http://www.typescriptlang.org/Playground/#src=class%20Book%20%7B%0A%20%20%20%20public%20BookId%3a%20number;%0A%20%20%20%20public%20Title%3a%20string;%0A%20%20%20%20public%20Author%3a%20string;%0A%20%20%20%20public%20Price%3a%20number;%0A%20%20%20%20public%20Description%3a%20string;%0A%7D%0A%0ABook%5B2%5D%20=%20function%20%28%29%7Balert%28%22hey%22%29;%7D%0Avar%20foo%20=%20new%20Book%5B2%5D%0A%20%20%20%20%20%20\">Try它

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