Angular 使用离子框架的角度未定义变量

我试图将JSON响应中的值设置为一些变量。但该值未设置，在尝试查看Console.log（）中的值时返回“undefined”

有人知道我做错了什么吗

public data: any;
carbs: string;
fat:any;
protein:any;

constructor(public navCtrl: NavController,public userprovider: UserProvider) {

    //returns json array
    this.user = this.userprovider.getUser(userid);

    this.user.toPromise().then(res => {

        this.carbs = res[0].carbs;
        this.fat = res[0].fat;
        this.protein = res[0].protein;

    });

    console.log(this.carbs);
   //pass the data here
     this.data = {"Macros":[{"Macros":"Prot","time":this.protein,"color":"#3fa9f5","hover":"#57c0f5"},{"Macros":"Carb","time":this.carbs,"color":"rgb(236, 240, 241)","hover":"rgb(236, 240, 241)"},{"Macros":"Fat","time":this.fat,"color":"rgb(52, 73, 94)","hover":"rgb(52, 73, 94)"}]};


}

---

这是因为

console.log（this.carbs）在
this.carbs=res[0]之前启动已完成。因此，与其在范围外调用函数，不如在范围内调用它

从以下位置调用函数：

 this.user.toPromise().then(res => {

        this.carbs = res[0].carbs;
        this.fat = res[0].fat;
        this.protein = res[0].protein;
        this.yourFunction(res[0].protein, res[0].carbs, res[0].fat );
    });

。
.

是否确定this.user未定义？此用户返回res=>中的json、console.log（res[0].carbs）并输出正确的值。ionViewDidLoad（）{}使用此函数。复制粘贴您的代码到其中，并检查发生了什么。此处也未定义。原因很可能是在此之前。carbs=res[0]。carbs；line console.log（this.carbs）；已启动。相同：错误类型错误：“this.data未定义”请前来聊天，除非stackoverflow将阻止评论
yourFunction(protein, carbs, fat){
 this.data = {"Macros":[{"Macros":"Prot","time":protein,"color":"#3fa9f5","hover":"#57c0f5"},{"Macros":"Carb","time":carbs,"color":"rgb(236, 240, 241)","hover":"rgb(236, 240, 241)"},{"Macros":"Fat","time":fat,"color":"rgb(52, 73, 94)","hover":"rgb(52, 73, 94)"}]};
}