Not getting complete data in ssrs Report

I have created a SSRS  report in which It shows few items not complete I have tried a lot but not getting the issue 

In visual studio i used Matrix Report 

It should have to show 20 Items against ItemGroupId but it Shows only 4 items ,

what should be the possible error 

here is DP class

private void insertTmpTable()
{
    QueryRun queryrun = new QueryRun(this.parmQuery());


    InventTrans inventTrans;
    InventTable  inventTable;
    PurchLine  purchLine;
    InventItemGroupItem  inventItemGroupItem ;

     ProcCategoryCommodityCodesContract  contract = this.parmDataContract() as ProcCategoryCommodityCodesContract;



    while (queryrun.next())
    {
        inventTable    =   queryrun.get(tableNum(inventTable));
        inventTrans    =   queryrun.get(tableNum(InventTrans));
        purchLine      =   queryrun.get(tableNum(purchLine));


         purchaseCategoryTmp.FromDate = fromDate;
        purchaseCategoryTmp.ToDate = toDate;



            //purchaseCategoryTmp.ItemId         = inventTrans.ItemId;
            purchaseCategoryTmp.ItemId         =inventTable.ItemId;
            purchaseCategoryTmp.ItemName       = inventTable::find(purchaseCategoryTmp.ItemId).itemName();
            purchaseCategoryTmp.PurchPrice     = purchLine.PurchPrice;
            purchaseCategoryTmp.HigestPrice    = this.HigestPrice(purchaseCategoryTmp.ItemId);
            purchaseCategoryTmp.LowestPrice    = this.LowestPrice(purchaseCategoryTmp.ItemId);
            purchaseCategoryTmp.Qty            = this.TotalQty(purchaseCategoryTmp.ItemId);
            purchaseCategoryTmp.ItemGroupId    = InventItemGroupItem::findByItemIdLegalEntity(purchaseCategoryTmp.ItemId).ItemGroupId;

            purchaseCategoryTmp.insert();
    }
}

Please guide me