WFA - 從SQL Server C＃和TreeView

Question

我一直在使用SQL Server和C＃填充在Windows應用程序中TreeView控件：

CREATE TABLE [dbo].[myTable] 
(
    [ID] [int] IDENTITY(1,1) NOT NULL, 
    [title] [varchar](255) NOT NULL, 
    [parentID] [int] NULL, 

    CONSTRAINT [PK_myTable] 
     PRIMARY KEY CLUSTERED ([ID] ASC) 
) 

插入一些分層數據

SET IDENTITY_INSERT myTable ON 
GO 

INSERT INTO myTable(ID, title, parentID) 
VALUES(1, 'Microsoft', NULL) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(2, 'C#', 1) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(3, 'VB.net', 1) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(4, 'Open Source', NULL) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(5, 'Python', 4) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(6, 'Ruby', 4) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(7, 'PHP', 4) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(8, 'Perl', 4) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(9, 'Java', 4) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(10, 'LinQ', 2) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(11, '5.2', 7) 

INSERT INTO myTable(ID, title, parentID) 
VALUES(12, '4.4', 7) 
GO 

SET IDENTITY_INSERT myTable OFF 
GO 

定義根值

CREATE PROCEDURE viewMyTable 
AS 
BEGIN 
    SELECT ID, title, ISNULL(parentID, 0) AS parentID 
    FROM myTable 
END 

添加同桌關鍵contraint。

ALTER TABLE [dbo].[myTable] WITH CHECK 
    ADD CONSTRAINT [FK_myTable_myTable] 
    FOREIGN KEY([parentID]) REFERENCES [dbo].[myTable] ([ID]) 
GO 

ALTER TABLE [dbo].[myTable] CHECK CONSTRAINT [FK_myTable_myTable] 

而樹視圖中沒有任何東西。誰能幫我？

enter image description here

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Answer 1

希望這有助於你。

WITH f(ID, Title, Level, Sort) 
AS(
    SELECT ID, Title, 0 AS Level, ROW_NUMBER() OVER(ORDER BY ID) AS Sort 
    FROM myTable 
    WHERE parentID IS NULL 

    UNION ALL 

    SELECT B.ID, B.Title, A.Level + 1, A.Sort 
    FROM f A, myTable B 
    WHERE A.Id = B.parentID 
) 
SELECT * 
FROM f 
ORDER BY Sort, Level