为BindingList添加Sort

最近在优化WPF性能时， 发现在特定条件下BindingList比ObservableCollection性能更高， 因为它提供Disable/Enable 更改通知的方法。这样我们可以不需要很频繁的通知UI去更新， 而是等所有操作都做完后再通知。

然而， 默认的BindingList不支持Sort， 需要我们实现。

 public class SortableBindingList<T> : BindingList<T>
    {
        // Fields
        private bool isSorted;
        private ListSortDirection listSortDirection;
        private PropertyDescriptor propertyDescriptor;
 
        // Methods
        public SortableBindingList()
        {
        }
 
        public SortableBindingList(IList<T> list)
            : this()
        {
            base.Items.Clear();
            foreach (T local in list)
            {
                base.Add(local);
            }
        }
 
        protected override void ApplySortCore(PropertyDescriptor prop, ListSortDirection direction)
        {
            (base.Items as List<T>).Sort(this.GetComparisionDelegate(prop, direction));
        }
 
        private Comparison<T> GetComparisionDelegate(PropertyDescriptor propertyDescriptor, ListSortDirection direction)
        {
            return delegate(T t1, T t2)
            {
                int num2;
                ((SortableBindingList<T>)this).propertyDescriptor = propertyDescriptor;
                ((SortableBindingList<T>)this).listSortDirection = direction;
                ((SortableBindingList<T>)this).isSorted = true;
                int num = (direction == ListSortDirection.Ascending) ? 1 : -1;
                if (propertyDescriptor.PropertyType == typeof(string))
                {
                    num2 = StringComparer.CurrentCulture.Compare(propertyDescriptor.GetValue(t1), propertyDescriptor.GetValue(t2));
                }
                else
                {
                    num2 = Comparer.Default.Compare(propertyDescriptor.GetValue(t1), propertyDescriptor.GetValue(t2));
                }
                return (num * num2);
            };
        }
 
        protected override void RemoveSortCore()
        {
            this.isSorted = false;
            this.propertyDescriptor = base.SortPropertyCore;
            this.listSortDirection = base.SortDirectionCore;
        }
 
        // Properties
        protected override bool IsSortedCore
        {
            get
            {
                return this.isSorted;
            }
        }
 
        protected override ListSortDirection SortDirectionCore
        {
            get
            {
                return this.listSortDirection;
            }
        }
 
        protected override PropertyDescriptor SortPropertyCore
        {
            get
            {
                return this.propertyDescriptor;
            }
        }
 
        protected override bool SupportsSortingCore
        {
            get
            {
                return true;
            }
        }
    }

调用RaiseListChangedEvents = false 或者RaiseListChangedEvents = true来控制更改通知， 

调用ResetBindings（）来全部更新， 或者ResetItem（index）来更新指定索引