Angular2/JavaScript-按1递增/递减(单击)
我想在用户按下add按钮时递增/递减,然后相应地更新amount值。我试过几次,但不幸的是我没有成功 代码如下:Angular2/JavaScript-按1递增/递减(单击),javascript,angular,Javascript,Angular,我想在用户按下add按钮时递增/递减,然后相应地更新amount值。我试过几次,但不幸的是我没有成功 代码如下: addToCart(){ this.amount = 1; } addItem(){ this.amount++; console.log('plus is : '+this.amount++) } removeItem(){ this.amount--; console.log('plus is : '+this.amount
addToCart(){
this.amount = 1;
}
addItem(){
this.amount++;
console.log('plus is : '+this.amount++)
}
removeItem(){
this.amount--;
console.log('plus is : '+this.amount--)
}
HTML:
添加
-
{{amount}}
+
错误在于使用++
export class HelloWorld {
public amount:number;
addToCart(){
this.amount = 1;
}
addItem(){
this.amount=this.amount+1;
console.log('plus is : '+this.amount)
}
removeItem(){
this.amount=this.amount-1;
console.log('plus is : '+this.amount)
}
}
您的JS代码是否在控制器中?您的控制器如何包含在视图中?是的!它不在构造函数()的范围内。顺便说一句,即使当前代码有效,它也会将数量增加/减少2,因为您在
console.log
之前使用的是post increment(即++
),也在console.log
语句中。如果我们有重复的按钮,您的解决方案将不起作用。。。它将同时递增/递减所有其他按钮
export class HelloWorld {
public amount:number;
addToCart(){
this.amount = 1;
}
addItem(){
this.amount=this.amount+1;
console.log('plus is : '+this.amount)
}
removeItem(){
this.amount=this.amount-1;
console.log('plus is : '+this.amount)
}
}