linq to sql实现无限递归查询
转:http://topic.csdn.net/u/20120628/17/cedc4661-39b6-42c9-9ba1-a1d8e3244142.html
CREATE TABLE [dbo].[Tim_LinqTable]( [Id] int PRIMARY KEY IDENTITY(1,1) NOT NULL, [Name] [varchar](50) NOT NULL, [Parent] int NOT NULL, ) GO INSERT INTO [Tim_LinqTable] SELECT 'A',0 UNION ALL SELECT 'A1',1 UNION ALL SELECT 'A2',1 UNION ALL SELECT 'B1',2 UNION ALL SELECT 'B2',3 UNION ALL SELECT 'C1',4 UNION ALL SELECT 'C2',4 UNION ALL SELECT 'D1',5 UNION ALL SELECT 'D2',5 UNION ALL SELECT 'D3',5 GO WITH temp AS ( SELECT * FROM [Tim_LinqTable] WHERE Parent = 3 UNION ALL SELECT m.* FROM [Tim_LinqTable] AS m INNER JOIN temp AS child ON m.Parent = child.Id ) SELECT * FROM temp GO --查询 Parent=3 的所有子数据结果如下: Id Name Parent ----------- -------------------------------------------------- ----------- 5 B2 3 8 D1 5 9 D2 5 10 D3 5 (4 row(s) affected)
void Main() { var query=GetClassID(3); Console.WriteLine("Id\tName\tParent"); query.ToList().ForEach(q=>Console.WriteLine("{0}\t{1}\t{2}",q.Id,q.Name,q.Parent)); /* Id Name Parent 5 B2 3 8 D1 5 9 D2 5 10 D3 5 */ } public IEnumerable<Tim_LinqTable> GetClassID(int p_id) { var query =from c inthis.Tim_LinqTables where c.Parent == p_id select c; return query.ToList().Concat(query.ToList().SelectMany(t => GetClassID(t.Id))); }
可用于角色和权限的管理方面