Question

我正在使用离子2

这是我的模板代码

 <div class="messagesholder" *ngFor="let chat of chatval | orderby:'[date]'; let last = last">
           {{last ? callFunction() : ''}}  

         <div *ngIf="chat.sender == currentuser || chat.receiver == currentuser">
                   <p *ngIf="msgdate === undefined"  class="chat-date" #ChatDate id="ChatDate" >{{chat.date | amDateFormat:'LL'}}</p>
                   {{checkdate(chat.date)}}
         </div> 

         <div class="message" *ngIf="chat.sender == currentuser || chat.receiver == currentuser" [ngClass]="{'me': currentuser == chat.sender}">
                <div class='image' *ngIf="chat.path" >
                  <img *ngIf="chat.path" [src]="chat.path" imageViewer/><br>
                  <span *ngIf="chat.path_text">{{chat.path_text}}</span>
                  <span style="font-size:9px;">{{chat.date | amDateFormat:'hh:mmA'}}</span>
                </div> 
                 <div *ngIf="chat.message_text">
                 <span>{{chat.message_text}}</span>
                 <span style="font-size:9px;">{{chat.date | amDateFormat:'hh:mmA'}}</span>
                 </div>
          </div>
     </div>

这是我的功能

checkdate(i)
  {
    console.log("date");
    console.log(i);
    this.msgdate=i;
  }

我需要相同的日期值不重复。因为我使用此函数获取输入元素值{{checkdate（chat.date）}}。

但我得错了。

Error in ./ChatPage class ChatPage - caused by: Expression has changed after it was checked. Previous value: 'true'. Current value: 'false'.

我该如何解决这个问题......

请建议我，

由于

Answer 1

您收到以下错误，因为您正在尝试修改在循环语句中执行后端处理的对象。

Error in ./ChatPage class ChatPage - caused by: Expression has changed after it was checked. Previous value: 'true'. Current value: 'false'.

如果您想获得唯一日期，那么您可以尝试以下示例，它将为您提供来自您的收藏集的唯一chatDate：

let Values = this.chatval.map(function (item) { return item["date"]; }).filter(this.OnlyUnique);

OnlyUnique(value, index, self): any {
    return self.indexOf(value) === index;
}

Ionic 2聊天页面重复相同的值

1 个答案: