JAVA高级面试进阶训练营视频教程

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帮助类：

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

        public SortBindingHelper() : base() { }

        public SortBindingHelper(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), 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)
        {
            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());
        }
    }

使用方式：

 private void NewMethod()
        {
            List<StudentInfo> list = new List<StudentInfo>();
            for (int i = 1; i <= 50; i++)
            {
                StudentInfo stu = new StudentInfo();
                stu.NameA = "学生aaaaaaaa" + i;
                string str = i.ToString().PadLeft(3, '0');//001
                stu.Age = str;
                list.Add(stu);
            }

            SortBindingHelper<StudentInfo> temp = new SortBindingHelper<StudentInfo>();
            foreach (StudentInfo item in list)
            {
                temp.Add(item);
            }

            this.dgvList.DataSource = temp;
        }