设置当前课程的属性：currentLesson。很明显，它将保存所选课程的"编号"。每次单击按钮时，将currentLesson值设置为"编号"/按钮顺序，即第一个按钮为" 1 "，第二个按钮为" 2 "，依此类推。如果currentLesson与其顺序不同，则可以使用[disabled]属性禁用每个按钮。

• • 超文本标记语言**

<button  (click)="currentLesson = '1'"
         [disabled]="currentLesson !== '1'" class="primair">
           Start lesson</button>
  <button (click)="currentLesson = '2'"
         [disabled]="currentLesson !== '2'" class="primair">
           Start lesson</button>
 .....//so on

• • typescript **

currentLesson:string;

  classes = [
{
  name: 'string',
  level: 'string',
  code: 'number',
  currentLesson: '1'
}]

constructor(){
  this.currentLesson=this.classes[0].currentLesson
}

DEMO
将所有内容放入循环中：

• • 超文本标记语言**

<div *ngFor="let class of classes; let i = index">
   <button [disabled]="currentLesson !== i + 1" class="primair">
           Start lesson {{i +  1}}</button>
</div>

• • typescript **

currentLesson:string;

classes = [
{
  name: 'Lesson1',
  level: 1,
  code: 1,
},{
  name: 'Lesson2',
  level: 1,
  code: 2,
},
{
  name: 'Lesson3',
  level: 2,
  code: 3,
}]

DEMO

my.component.html:

<button [disabled]="isSubmitBtnDisabled" (click)="addGame()">Send</button>

my.component.ts:

export class My implements OnInit {
  isSubmitBtnDisabled: boolean= false;

   private someMethodYouCalled() {
      this.isSubmitBtnDisabled = true;   //Controls if button is disabled
   }
}

export class ClassComponent implements OnInit {
  classes = [
{
  name: 'string',
  level: 'string',
  code: 'number',
  currentLesson: '1'
}]

checkCurrentLession(current){

 this.classes.forEach((obj)=>{
    if(obj.currentLession == current){
      return true;
    }

  });
  return false;
}

<ul class="table lessonOverview">
        <li>
          <p>Lesson 1</p>
          <button [routerLink]="['/lesson1']" 
             [disabled]="checkCurrentLession(1)" class="primair">
               Start lesson</button>
        </li>
        <li>
          <p>Lesson 2</p>
          <button [routerLink]="['/lesson2']" 
             [disabled]="!checkCurrentLession(2)" class="primair">
               Start lesson</button>
        </li>
     </ul>

<div class="col-md-12">
      <p style="color: #28a745; font-weight: bold; font-size:25px; text-align: right " >Total Productos a pagar= {{ getTotal() }} {{ getResult() | currency }}
      <button class="btn btn-success" type="submit" [disabled]="!getResult()" (click)="onSubmit()">
        Ver Pedido
      </button>
     </p>
    </div>