学步园

最近拿Linq出來玩,看怎麼用它去查詢TreeView裡的東西,可以下查詢條件,找出TreeView底下的Nodes是否有符合的Text或是其它屬性,這次就試著用Linq來找看看~

 

比如說TreeView長的像下面這個樣子,要怎麼去找出符合我們輸入的關鍵字.

剛開始試的時候,就遇到一個問題,如果我用下面的寫法,那麼只會找該層的Nodes,子Nodes就不會去找.

view source

print?

1	var nodes = from TreeNode chi in treeView1.Nodes

2	where chi.Text.ToUpper().Contains(textBox1.Text.ToUpper())

3	select chi;

看樣子似乎沒辨法直接這麼去找,除非treeView1能夠一次return全部的Nodes,只好從邏輯面著手去完成.

view source

print?

01	private void button1_Click(object sender, EventArgs e)

02

{

03	if (textBox1.Text.Length == 0)

04

{

05	MessageBox.Show("請輸入查詢條件");

06	textBox1.Focus();

07

return;

08

}

09

10	this.Cursor = Cursors.WaitCursor;

11	treeView1.BeginUpdate();

12

13	treeView1.CollapseAll();

14	int Cnt = 0;

15	FindNode(treeView1.Nodes, ref Cnt);

16	treeView1.EndUpdate();

17

18	this.Cursor = Cursors.Default;

19

20	MessageBox.Show(string.Format("找到 {0} 筆", Cnt));

21

}

22

23	private void FindNode(TreeNodeCollection treeNodeCollection, ref int Count)

24

{

25	var undoRedNode = from TreeNode chi in treeNodeCollection

26	where chi.ForeColor == Color.Red

27	select chi;

28

29	foreach (TreeNode tn in undoRedNode)

30

{

31	tn.ForeColor = Color.Black;

32

}

33

34	var nodes = from TreeNode chi in treeNodeCollection

35	where chi.Text.ToUpper().Contains(textBox1.Text.ToUpper())

36	select chi;

37

38	foreach (TreeNode tn in nodes)

39

{

40	treeView1.SelectedNode = tn;

41	tn.Expand();

42

Count++;

43	tn.ForeColor = Color.Red;

44

}

45

46

47	foreach (TreeNode tn in treeNodeCollection)

48

{

49	if (tn.GetNodeCount(false) > 0)

50

{

51	FindNode(tn.Nodes, ref Count);

52

}

53

}

54

55

}

 

這麼一來,只要輸入查詢條件去查詢,就可以將符合條件的Node展開,並改為紅色的字.