角度2的警报信息

Question

登录凭据错误时，我无法显示警告消息。它不显示在else范围内，但是当我在if范围中输入消息时，它会显示？有人能帮我吗？

 message:string;

    //login user credentials to authenticate
    submitForm() {


        this.service.login(this.login.username, this.login.password)
            .subscribe(data => {
                if(data == true){


                }else {
                    this.message = "Username or Password Invalid";

                }
            });


}

// HTML

  <div *ngIf="message" class="alert alert-danger text-center " style="width: 40%; font-size: 16px" >{{message}}</div>

Answer 1

您必须更改作业：

if (data === true)  is the solution

更好的解决方案是

if ( data ) 

Answer 2

试试这个

message:string;
submitForm() {
    this.service.login(this.login.username, this.login.password)
        .subscribe(data => {
            if(!data){
                this.message = "Username or Password Invalid";
            }
        });
}