angular - pagination ngx bootstrap for angular2 -

i have probleme pagination first have 21 objects in database when them want show them pagination , things works think pagination module has number of row display default took 10 row per page , not 4 per page

export class groupcomponent implements oninit {   public maxsize:number = 5;   bigtotalitems:number = 175;   bigcurrentpage:number = 1;   numpages:number = 0;   itemsperpage = 4;   groups : any;    myvar:boolean=false;   constructor(private groupeservice:dataserviceservice) {      parent.displaygroupeicon();   }    ngoninit() {     this.getlistgroups();   }  getlistgroups(){    this.groupeservice.getgroupsbypageandsize(this.bigcurrentpage-1,this.itemsperpage).subscribe(groups => {   this.groups=groups;   this.numpages=groups.totalpages;   this.bigtotalitems=groups.totalelements;   this.myvar = true;              });  } 

and template

   <table class="table table-striped">            <thead>             <tr>              <th >identifiant </th>               <th >nom </th>                 <th >image</th>                  <th ></th>                 <th ></th>             </tr>            </thead>            <tbody *ngif="myvar">             <tr *ngfor="let groupe of groups.content" >            <td >{{groupe.idgroupe}} </td>            <td >{{groupe.nom}} </td>            <td >{{groupe.imageurl}}</td>      <td ><button  class="btn btn-warning" >update <i class="fa fa-cog" aria-hidden="true"></i></button></td>             <td ><button  class="btn ink-reaction btn-danger">delete <i class="fa fa-trash-o" aria-hidden="true"></i></button></td>             </tr>            </tbody>         </table>    <div class="col-md-6">   <pagination [totalitems]="bigtotalitems" [(ngmodel)]="bigcurrentpage" [maxsize]="maxsize" class="pagination-sm"               [boundarylinks]="true" [rotate]="false"  (click)="getlistgroups()"></pagination> </div> bigtotalitems : {{bigtotalitems| json}}  numpages : {{numpages|json}} 

heeelp pleaseee , in advice.

i resolv adding [itemsperpage]="itemsperpage" directive in selector of pagination