我已经定义了一个这样的接口:
interface IModal {
content: string;
form: string;
href: string;
$form: JQuery;
$message: JQuery;
$modal: JQuery;
$submits: JQuery;
}
我这样定义一个变量:
var modal: IModal;
然而，当我尝试设置modal属性时，它会给我一个消息说
"cannot set property content of undefined"
是否可以使用接口来描述我的模态对象，如果是这样，我应该如何创建它?
当前回答
使用你的界面就可以做到
class Modal() {
constructor(public iModal: IModal) {
//You now have access to all your interface variables using this.iModal object,
//you don't need to define the properties at all, constructor does it for you.
}
}
其他回答
使用你的界面就可以做到
class Modal() {
constructor(public iModal: IModal) {
//You now have access to all your interface variables using this.iModal object,
//you don't need to define the properties at all, constructor does it for you.
}
}
您可以使用Class设置默认值。
没有类构造函数:
interface IModal {
content: string;
form: string;
href: string;
isPopup: boolean;
};
class Modal implements IModal {
content = "";
form = "";
href: string; // will not be added to object
isPopup = true;
}
const myModal = new Modal();
console.log(myModal); // output: {content: "", form: "", isPopup: true}
使用类构造函数
interface IModal {
content: string;
form: string;
href: string;
isPopup: boolean;
}
class Modal implements IModal {
constructor() {
this.content = "";
this.form = "";
this.isPopup = true;
}
content: string;
form: string;
href: string; // not part of constructor so will not be added to object
isPopup: boolean;
}
const myModal = new Modal();
console.log(myModal); // output: {content: "", form: "", isPopup: true}
你可以这样做
var modal = {} as IModal
该界面有5种使用方式。
interface IStudent {
Id: number;
name: string;
}
Method 1. all fields must assign data.
const obj1: IStudent = { Id: 1, name: 'Naveed' };
Method 2. my favorite one
const obj2 = { name: 'Naveed' } as IStudent ;
Method 3.
const obj3 = <IStudent >{name: 'Naveed'};
Method 4. use partial interface if all fields not required.
const obj4: Partial<IStudent > = { name: 'Naveed' };
Method 5. use ? Mark with interface fields if all fields not required.
const obj5: IStudent = { name: 'Naveed' };
目前发布的许多解决方案都使用类型断言，因此如果在实现中遗漏了所需的接口属性，也不会抛出编译错误。
对于那些对其他健壮、紧凑的解决方案感兴趣的人:
选项1:实例化一个实现接口的匿名类:
new class implements MyInterface {
nameFirst = 'John';
nameFamily = 'Smith';
}();
选项2:创建一个实用函数:
export function impl<I>(i: I) { return i; }
impl<MyInterface>({
nameFirst: 'John';
nameFamily: 'Smith';
})
