C# ICollection筛选器错误转换类型

我已经过滤了我的收藏

这是我的密码

 public ICollectionView LogEntriesStoreView { get; set; }

  var collection = new ObservableCollection<Service>(this._model.GetService());

   this.LogEntriesStoreView = CollectionViewSource.GetDefaultView(collection);

            this.LogEntriesStoreView.Filter += new FilterEventHandler(ShowOnlyBargainsFilter);


private void ShowOnlyBargainsFilter(object sender, FilterEventArgs e)
        {
            AuctionItem product = e.Item as AuctionItem;
            if (product != null)
            {
                // Filter out products with price 25 or above
                if (product.CurrentPrice < 25)
                {
                    e.Accepted = true;
                }
                else
                {
                    e.Accepted = false;
                }
            }
        }

现在我得到了这个错误 System.Predicate中的隐式类型转换System.Windows.Data.Filter EventHandler不能为空

this._view = new TViewType();
            this._model = new ServiceModel();
            this.Service = new ObservableCollection<Service>(this._model.GetService());
            this.OkCommand = new RelayCommand(o => this.OKRun());
            this.LostFocusCommand = new RelayCommand(o => this.LostFocusOKRun());

            // в переменную получаем нашу коллекцию
            var collection = new ObservableCollection<Service>(this._model.GetService());
            // инициализируем поле типа ICollectionView нашей коллецией
            this.LogEntriesStoreView = CollectionViewSource.GetDefaultView(collection);

            this.LogEntriesStoreView.Filter = new Predicate<object>(Contains);

            this.LogEntriesStoreView.Filter += new FilterEventHandler(ShowOnlyBargainsFilter);


            this._view.SetDataContext(this);
            this._view.ShowIView();
        }

        private void OKRun()
        {
            MessageBox.Show("One Click");
        }

        private void LostFocusOKRun()
        {
            MessageBox.Show("LostFocus");
        }

        private void TextChanged()
        {

        }

        private void ShowOnlyBargainsFilter(object sender, FilterEventArgs e)
        {

        }

        public bool Contains(object de)
        {

            return true;
        }

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完整代码，我在我的代码中添加了一个谓词。例如，在msdn上生成的所有事件处理程序都应适用于CollectionViewSource LogEntriessStoreView

CollectionView和CollectionViewSource的过滤器实现之间存在差异

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我理解它，但我做的每件事都是举例说明，一定是一些语法错误导致了这一点。您能在这里添加相关代码吗？您是否遵循了每个步骤？检查是否已分配类似于myCollectionView.Filter=new PredicateContains；的内容；。