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訂閱前後完整能否請您回答評論等待HTTP請求執行下一行angular2
class TextComp
{
result: string;
constructor() {
this.getdata().subscribe(result => {
console.log("result received");
this.result = result;
});
console.log("called before result received " + this.result);
//this.result is NULL/UNDEFINED because this line executed before data received
// So how we can eliminate this situation??? or
// Is there any way to make synchronus call to http in angular 2
}
getdata() {
return http.get('test.json')
.map(response => response.json());
}
}
質疑那麼我們如何能夠消除這種情況???或 有沒有什麼辦法讓SYNCHRONUS調用HTTP在角2
您不希望它是同步的,因爲這會讓您的應用程序在等待響應時掛起。無論您需要對結果做什麼,您都必須在訂閱回調中執行操作。 –