DataGridView 绑定List 时 排序问题的解决

public class SortableBindingList <T> : BindingList <T>
{
private bool isSortedCore = true;
private ListSortDirection sortDirectionCore = ListSortDirection.Ascending;
private PropertyDescriptor sortPropertyCore = null;
private string defaultSortItem;

public SortableBindingList() : base() { }

public SortableBindingList(IList <T> list) : base(list) { }

protected override bool SupportsSortingCore
{
get { return true; }
}

protected override bool SupportsSearchingCore
{
get { return true; }
}

protected override bool IsSortedCore
{
get { return isSortedCore; }
}

protected override ListSortDirection SortDirectionCore
{
get { return sortDirectionCore; }
}

protected override PropertyDescriptor SortPropertyCore
{
get { return sortPropertyCore; }
}

protected override int FindCore(PropertyDescriptor prop, object key)
{
for (int i = 0; i < this.Count; i++)
{
if (Equals(prop.GetValue(this[i]), key)) return i;
}
return -1;
}

protected override void ApplySortCore(PropertyDescriptor prop, ListSortDirection direction)
{
isSortedCore = true;
sortPropertyCore = prop;
sortDirectionCore = direction;
Sort();
}

protected override void RemoveSortCore()
{
if (isSortedCore)
{
isSortedCore = false;
sortPropertyCore = null;
sortDirectionCore = ListSortDirection.Ascending;
Sort();
}
}

public string DefaultSortItem
{
get { return defaultSortItem; }
set
{
if (defaultSortItem != value)
{
defaultSortItem = value;
Sort();
}
}
}

private void Sort()
{
List <T> list = (this.Items as List <T> );
list.Sort(CompareCore);
ResetBindings();
}

private int CompareCore(T o1, T o2)
{
int ret = 0;
if (SortPropertyCore != null)
{
ret = CompareValue(SortPropertyCore.GetValue(o1), SortPropertyCore.GetValue(o2), SortPropertyCore.PropertyType);
}
if (ret == 0 && DefaultSortItem != null)
{
PropertyInfo property = typeof(T).GetProperty(DefaultSortItem, BindingFlags.Public | BindingFlags.GetProperty | BindingFlags.Instance | BindingFlags.IgnoreCase, null, null, new Type[0], null);
if (property != null)
{
ret = CompareValue(property.GetValue(o1, null), property.GetValue(o2, null), property.PropertyType);
}
}
if (SortDirectionCore == ListSortDirection.Descending) ret = -ret;
return ret;
}

private static int CompareValue(object o1, object o2, Type type)
{
//这里改成自己定义的比较
if(o1 == null)return o2==null ? 0 : -1;
else if(o2 == null) return 1;
else if (type.IsPrimitive || type.IsEnum) return Convert.ToDouble(o1).CompareTo(Convert.ToDouble(o2));
else if (type == typeof(DateTime)) return Convert.ToDateTime(o1).CompareTo(o2);
else return String.Compare(o1.ToString().Trim(), o2.ToString().Trim());
}
}