我很难使用Angular2中的数据驱动方法来设置最大值。我想将输入的最大值设置为一个名为UserLimit的属性,我从Firebase获得。这是我的代码:
component.ts
import { Component, OnInit, AfterViewInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators, FormControl } from "@angular/forms";
import { FiredbService } from '../services/firedb.service';
import { AuthService } from '../services/auth.service';
import { AngularFireDatabase, FirebaseListObservable, FirebaseObjectObservable } from 'angularfire2/database';
@Component({
selector: 'my-dashboard',
styleUrls: ['./recibirpago.component.scss'],
templateUrl: './recibirpago.component.html'
})
export class RecibirpagoComponent implements OnInit, AfterViewInit {
myForm2: FormGroup;
uid: string;
userLimit: any;
constructor(private fb: FormBuilder,
private dbfr: FiredbService,
private db: AngularFireDatabase,
private authService: AuthService) {
this.myForm2 = this.fb.group({
email: ['', Validators.email],
clpmount: ['', [Validators.required, Validators.max(this.userLimit)]]
});
}
ngOnInit() {
this.uid = this.authService.getUserUid();
}
ngAfterViewInit() {
this.dbfr.getUserLimit(this.uid).subscribe(snapshot => {
this.userLimit = snapshot.val().accountLimit;
console.log(this.userLimit);
})
}
例如,如果我写的,例如validators.max(5000),它有效,但是如果我尝试从firebase获取数据不起作用。
感谢您的帮助!
问题是构造函数在 ngafterviewinit之前执行,因此您当时没有UserLimit的值。
而是在获取数据的订阅中使用setVAlidators
方法。
类似的东西:
构造函数
this.myForm2 = this.fb.group({
email: ['', Validators.email],
clpmount: ['', Validators.required] // <-- not here
});
ngafterviewinit
ngAfterViewInit() {
this.dbfr.getUserLimit(this.uid).subscribe(snapshot => {
this.userLimit = snapshot.val().accountLimit;
console.log(this.userLimit);
const clpControl = this.myForm2.get(`clpmount');
clpControl.setValidators(Validators.max(this.userLimit)); // <-- HERE
clpControl.updateValueAndValidity();
})
}
注意:未检查语法。