angular - 无法设置 Angular 未定义错误的属性 'nUserId'

Question

当我的表单复选框切换时，我试图调用一个 ReST API。当我调用调用 api 的方法时，我收到类似

的错误

Cannot set property 'nUserId' of undefined at

我的 html 文件包含以下代码，

<div>
  <button mat-raised-button color="primary" (click)="getUserPermisionsByUsernameSearch()">
    Search</button>
</div>
<br /> <br><br />
<div *ngIf="userPermissionObj">
  <div><label for="pl">Permission Level:</label> {{userPermissionObj.sPermLevel}} </div>
  <label for="pm">Permissions:</label>
  <div *ngFor="let pt of permissionType">
    <label>
      <input type="checkbox" [value]="pt.id" [checked]="userPermissionObj.sPermissionType == pt.name ? true : false"
        (change)="updateUserPermisionsByUsername(userPermissionObj,pt)" />
      {{pt.name}} -- {{userPermissionObj.nUserId}}
    </label>

我的ts文件包含以下代码，

export class ModifyuserpermissionsComponent implements OnInit {
    selectedUser: string;
    selectedInstitution: string;
    filtertext: string;
    public status: boolean = false;
    public data = new Array();

    institutionalUsers: any;
    userNameDetails: any;
    userPermissionObj: any;
    permissionRequestUser: any;
    modificationObj: any;
    userObj: any;
    permision: any;


    dataSource = new MatTableDataSource();
    selection = new SelectionModel<Element>(true, []);
    displayedColumns = ['UserId', 'PermissionId', 'PermissionLevel', 'PermissionType'];


    constructor(public dialog: MatDialog,
        public manageuserService: ManageuserService) { }

    ngOnInit() {

        this.manageuserService.loadUserListApiMethod()
            .subscribe((data: any) => { this.institutionalUsers = data });
    }
    loadUserForSearchPermission(event: any, obj: any) {
        if (event.isUserInput) {
            this.permissionRequestUser = obj.sUsername;
        }
    }

    permissionType = [
        { id: 1, name: 'R' },
        { id: 2, name: 'W' }
    ];

    getUserPermisionsByUsernameSearch() {
        var param: string = this.permissionRequestUser;
        this.manageuserService.getUserPermissionApiMethod(param)
            .subscribe((data: any) => { this.userPermissionObj = data });
    }

    updateUserPermisionsByUsername(userObj, permision) {
        this.modificationObj.nUserId = userObj.nUserId;
        this.modificationObj.name = permision.name;
        this.manageuserService.modifyUserPermissionApiMethod(this.userObj)
            .subscribe((data: any) => { this.institutionalUsers = data });
    }

}

有人可以指导我在这里找到错误的实现吗？

Answer 1

你是否初始化了modificationObj？

您正在尝试设置 undefined 对象的属性。它应该如下所示:

updateUserPermisionsByUsername(userObj, permision) {
  // this.modificationObj.nUserId = userObj.nUserId;
  // this.modificationObj.name = permision.name;

  this.modificationObj = {
    nUserId: userObj.nUserId,
    name: permision.name
  }
}