Error CS0103 The name 'query' does not exist in the current context. 
Error CS0103 The name 'First' does not exist in the current context. 
Error CS0103 The name 'query.First' does not exist in the current context.
Error CS0161 'PurchaseOrderService.GetAllProductstatusdetails()': 
Error CS1519 Invalid token '(' in class, struct, or interface member declaration
Error CS1519 Invalid token '(' in class, struct, or interface member declaration
Error CS1519 Invalid token 'return' in class, struct, or interface member declaration
Error CS1513 } expected

This is my Purchaseorderservices.cs page.

using QFT_POMS_SVC.Domain.POMS;
using System.Collections.Generic;
using System.Linq;


namespace QFT_POMS_SVC.Services.POMS
{
    public class PurchaseOrderService : IPurchaseOrderService
    {
        ProductStatusEntities entities = new ProductStatusEntities();
        private DBMapper _dbContext;
        private Result _result;
        private object query;

        public PurchaseOrderService()
        {
            _dbContext = new DBMapper();
            _result = new Result();
        }
        public IList<Distributor> GetAllDistributorsOp()
        {
            var query = from d in _dbContext.DistributorRepository select d;
            return query.ToList();
        }
        public IList<PurchaseOrder> GetAllPOByDistributorIdOp(int DistributorId)
        {
            var query = from po in _dbContext.PurchaseOrderRepository
                        where po.DistributorId == DistributorId
                        select po;

            return query.ToList();
        }

        public PurchaseOrder GetPODetailsOp(int PurchaseOrderId)
        {
            var query = from po in _dbContext.PurchaseOrderRepository
                        where po.Id == PurchaseOrderId
                        select po;

            return query.First();
        }

        private void UpdatePurchaseOrderItems(int purchaseorderid, List<PurchaseOrderItem> items)
        {
            foreach (var item in items)
            {
                var _item = _dbContext.PurchaseOrderItemsRepository.Where(po => po.Id == item.Id).First();
                _item.QtyReceived = item.QtyReceived;
                _item.Received = item.Received;
                _item.UnitCostReceived = item.UnitCostReceived;
                _item.Discontinued = item.Discontinued;
            }
            _dbContext.SaveChanges();
        }

        public Result UpdatePurchaseOrderOp(PurchaseOrder po)
        {
            var _purchaseOrder = GetPODetailsOp(po.Id);
            _purchaseOrder.deleted = po.deleted;
            _purchaseOrder.InvoiceDate = po.InvoiceDate;
            _purchaseOrder.InvoiceDueDate = po.InvoiceDueDate;
            _purchaseOrder.InvoiceNumber = po.InvoiceNumber;
            //_purchaseOrder.items.Clear();

            //_purchaseOrder.items = po.items;
            _purchaseOrder.PORcvdAmount = po.PORcvdAmount;

            UpdatePurchaseOrderItems(po.Id, po.items);


            _dbContext.SaveChanges();
            return _result;
        }

        public List<ProductStatusEntities> GetAllProductstatusdetails()
        {
            var query = from orditem in _dbContext.OrderItemRepository
                        from p in _dbContext.ProductRepository
                        from dpm in _dbContext.DistributorProductMappingRepository
                        from pwi in _dbContext.ProductWarehouseInventoryRepository
                        where
                        p.ProductTypeId == orditem.ProductId &&
                        dpm.ProductId == pwi.ProductId &&
                        dpm.ProductId == orditem.ProductId &&
                        orditem.Order.OrderStatusId == 20
                        group new { orditem, p, dpm.Distributor, dpm, pwi } by new
                        {
                            orditem.ProductId,
                            orditem.OrderId,
                            p.Name,
                            p.ProductTypeId,
                            Column1 = dpm.Distributor.Name,
                            dpm.StockStatus,
                            dpm.UnitPrice,
                            pwi.StockQuantity,
                            Column2 = p.StockQuantity
                        } into g
                        select new
                        {
                            g.Key.OrderId,
                            g.Key.ProductId,
                            productname = g.Key.Name,
                            g.Key.UnitPrice,
                            Distributorname = g.Key.Column1,
                            orderquantity = (int?)g.Sum(p => p.orditem.Quantity),
                            TotalQuantity = (int?)g.Sum(p => p.pwi.StockQuantity + p.dpm.StockStatus + p.p.StockQuantity);
        }

return query.First();
}

}