Question

我无法从来自API的JSON响应对象填充下拉列表。.

component.ts代码

for (let k in keys) {
        this.form.controls['id'].setValue(data[k].name);
        console.log(data[k].name);
    }
});

component.html代码

<mat-form-field>
    <mat-label>Select a User</mat-label>
    <mat-select formControlName="id">
        <mat-option *ngFor="let opt of options" [value]="opt.data" >
            {{ opt.data.name}}
        </mat-option>
    </mat-select>
</mat-form-field>

console.log（data）

0: {id: 1, name: "User1"}
1: {id: 2, name: "User2"}
2: {id: 3, name: "User3"}
3: {id: 4, name: "User4"}
...

console.log（data [k] .name）; //这是我在下拉菜单中需要的数据
```
  User1
  User2
  User3
  User4
  ...
```

console.log数据显示每个对象的索引。我的JSON对象非常简单。
看起来像：

[
 {
    "id": 1,
    "name": "User1"
 },
 {
    "id": 2,
    "name": "User2"
 },...
]

请让我知道我在做什么错。谢谢。

编辑
来了 Stackblitz Example

Answer 1

如果我正确理解了该问题，则您的API响应是一个列表，因此只需使用for循环将其绑定到Mat-Option。

HTML代码：

<mat-card>
    <form [formGroup]="form" (submit)="add()">
        <mat-form-field>
            <mat-label>Select a User</mat-label>
            <mat-select formControlName="id">
                                               \/\/
                <mat-option *ngFor="let key of users" [value]="key">
                    {{ key.name }}
                </mat-option>
            </mat-select>
        </mat-form-field>
        <br/>
            <div fxLayout>
                <div>
                    <button
                    mat-raised-button
                    color="accent" [disabled] = "form.invalid">Save
                </button>
            </div>
        </div>
    </form>
</mat-card>

TS代码：

getUsers(): void {
  this.usersService.getUsers().subscribe(users => {
        this.users = users;
        console.log(this.users)
  });
}

Forked_Stackblitz

Answer 2

尝试一下：

<mat-form-field>
    <mat-label>Select a User</mat-label>
    <mat-select formControlName="id">
            <mat-option *ngFor="let item of list" [value]="item" >
                {{ item.name }}
            </mat-option>
        </mat-select>
</mat-form-field>

根据此修改TS文件：

list:any=[];
 getUsers(): void {
        this.usersService.getUsers()
        .subscribe(users => {

            this.users = users;
            const data: User[] = this.users;
            console.log('data',data)
            console.log("object",Object.keys(data));
            const keys: number[] = Object.keys(data) as any;
            console.log("keys",keys);
            console.log("users",this.users);
            for (let k in keys) {
                this.form.controls['id'].setValue(data[k].name);
                console.log(data[k]);
                this.list.push(data[k]);
            }
        });
    }

将数据从JSON对象绑定到<mat-select>时遇到的问题

2 个答案: