title: Concat values of two dropdowns and show in input (Angular)
body: <p>I have 2 dropdowns. Here is html code of component.</p>
  
  <pre><code>&lt;div class="form-group"&gt;
        &lt;label&gt;{{l("RoomType")}}&lt;/label&gt;
       &lt;p-dropdown [disabled] = "!roomTypes.length"  [options]="roomTypes" autoWidth="false"  [style]="{'width':'100%'}" name="roomTypes" [autoWidth]="true" [(ngModel)]="room.roomTypeId"&gt;&lt;/p-dropdown&gt;
  &lt;/div&gt;
  
  &lt;div class="form-group"&gt;
          &lt;label&gt;{{l("RoomNumber")}}&lt;/label&gt;
          &lt;p-dropdown [disabled] = "!roomNumbers.length"  [options]="roomNumbers" autoWidth="false"  [style]="{'width':'100%'}" name="numberRoom" [autoWidth]="true" [(ngModel)]="room.roomNumber"&gt;&lt;/p-dropdown&gt;
  &lt;/div&gt;  
  </code></pre>
  
  <p>Here is how they populated in ts</p>
  
  <pre><code>getRoomTypes(): void {
      this._roomTypeService.getRoomTypesDropdownValues().subscribe(r =&gt; {
          r.items.forEach((value) =&gt; {
              this.roomTypes.push({label: value.name, value: value.id});
          });
      });
  }
  
  getRoomNumber(): void {
      for (let i = 1; i &lt;= 10; i++) {
          this.roomNumbers.push({label: i.toString(), value: i});
      }
  }
  </code></pre>
  
  <p>after those dropdowns, I have an input field, which I need  to populate with the concat label of 1 + 2 dropdown.</p>
  
  <p>Here is this input field</p>
  
  <pre><code>&lt;div class="form-group"&gt; 
                      &lt;label&gt;{{l("RoomName")}}&lt;/label&gt;
                      &lt;input #roomNameInput="ngModel" class="form-control" type="text" name="roomName" [(ngModel)]="room.roomName"   maxlength="32"&gt;
                  &lt;/div&gt;
  </code></pre>
  
  <p>I tried to do this like this <code>(ngModelChange)="setRoomName(room.roomTypeId,room.roomNumber)"</code> on both dropdowns. But it just getting id of options.</p>
  
  <p>How I can concat those labels, correctly?</p>