Foreach循环渲染，数据源改变时的重复渲染

@Observed 
export default class stu { 
  name : string; 
  age : number; 
  id : string; 
  
  constructor(name:string,age:number,id:string) { 
    this.name = name; 
    this.age = age; 
    this.id = id; 
  } 
}

import stu from '../common/bean/stu'; 
  
@Entry 
@Component 
struct fivePage { 
  @State simpleList: Array<stu> = [ 
    new stu('赵',10,'00001'), 
    new stu('钱',11,'00002'), 
    new stu('孙',12,'00003'), 
    new stu('李',13,'00004'), 
  ]; 
  
  build() { 
    Row() { 
      Column() { 
        ForEach(this.simpleList, (item : stu,index : number) => { 
          if (index % 2 === 0) { 
            ChildItem({student : item}) 
          } else { 
            ChildItemT({student : item}) 
          } 
        },(item : stu) => item.id)//这个key的定义需要具备唯一性，且不会发生改变 
      } 
    } 
  } 
} 
  
@Component 
struct ChildItem { 
  
  @ObjectLink student :stu; 
  
  build() { 
    Row() { 
      Column(){ 
        Text(this.student.id) 
      } 
      .width('30%') 
      Column(){ 
        Text(this.student.name) 
      } 
      .width('30%') 
      Column(){ 
        Text(this.student.age.toString()) 
      } 
      .width('40%') 
    } 
    .backgroundImage($r('app.media.startIcon')) 
    .onClick(()=>{ 
      this.student.age ++; 
    }) 
  } 
} 
  
@Component 
struct ChildItemT { 
  @ObjectLink student :stu; 
  
  build() { 
    Row() { 
      Column(){ 
        Text(this.student.id) 
      } 
      .width('30%') 
      Column(){ 
        Text(this.student.name) 
      } 
      .width('30%') 
      Column(){ 
        Text(this.student.age.toString()) 
      } 
      .width('40%') 
    } 
    .backgroundImage($r('app.media.icon')) 
    .onClick(()=>{ 
      this.student.age ++; 
    }) 
  } 
}