Angular 2 can not display list of item in html page

Question

it is me again.... I have problems displaying my array of items in the view, i always get this error. [Unhandled Promise rejection: Cannot set property 'stack' of undefined ; Zone: ; Task: Promise.then ; Value: TypeError: Cannot set property 'stack' of undefined]

Maybe i'm doing something wrong when it comes to the binding of the data in the html view.

   ngOnInit() : void{


        this._loadCoil.getAllCoils().subscribe(coils =>{ this.coils = coils;
            this.gridData = {
                data: this.coils.slice(this.currentPage, this.currentPage + this.displaySize),
                total: this.coils.length};

            for(let i = 0; i < this.coils.length; i++){
                let isFound = false;
                for (let j = 0; j < this.dropDownArray.length; j++){
                    if (this.dropDownArray[j] == this.coils[i].unit){
                        isFound = true;
                        break;
                    }
                }

                if(!isFound){
                    this.dropDownArray.push(this.coils[i].unit);
                }
            }
        }); 

    }

Basically i want to fill my array with unit names and display them on the website. (This part is working fine)

However, when i want to print the names on a page i get the before mentioned here. Here is my code snippet from the html page

  <div>
         <ul>
           <li *ngFor="let name in dropDownArray">{{name}}</li>
         </ul>

  </div>

Answer 1

而不是in ，它应该是of在迭代：

<li *ngFor="let name of dropDownArray">{{name}}</li>