微軟官方論壇無解：自繪ListBox的onPaint事件後滚动条好像不起做用了

lertulo 2009-03-26 08:20:26



//本来想重绘一个 ListBox，用来显示两行文字，可是继承 ListBox重写了OnPaint事件后，

//滚动条好像不起做用了，无论拉到哪里，都是从第一个向后显示。也就是说OnPaint好像有问题。   

  

//代码如下：   

  

  

1 using System;      

2 using System.Collections.Generic;      

3 using System.Text;      

4 using System.Windows.Forms;      

5 using System.Drawing;      

6 using System.Collections;      

7      

8      

9 namespace HappyFarmDotNet      

10 {      

11     class ListBoxEx : System.Windows.Forms.ListBox      

12     {      

13         public ListBoxEx()      

14         {      

15             ItemHeight = 65;      

16      

17             this.SetStyle(ControlStyles.UserPaint, true);      

18      

19             Click += new EventHandler(OnClick);      

20         }      

21         protected override void OnPaint(PaintEventArgs e)      

22         {      

23      

24             for (int i = 0; i < Items.Count; i++)      

25             {      

26                 if (SelectedIndex == i)      

27                 {      

28                     DrawSelectedItems(e, i);      

29                 }      

30                 else     

31                 {      

32                     DrawNomalItems(e,i);      

33                 }      

34             }      

35             base.OnPaint(e);      

36         }      

37      

38         private void OnClick(object sender, EventArgs e)      

39         {      

40             this.Refresh();      

41         }      

42         private void DrawNomalItems(PaintEventArgs e, int x)      

43         {      

44        //     e.Graphics.TranslateTransform(this.AutoScrollOffset.X, this.AutoScrollOffset.Y);      

45             e.Graphics.DrawRectangle(Pens.Beige, 1, (x * 65 + 1), 

               e.ClipRectangle.Width - 3, 45);      

46             e.Graphics.DrawString(Items[x].ToString(), 

                Font, Brushes.SkyBlue, 65, (x * 65) + 8);      

47         }      

48      

49         private void DrawSelectedItems(PaintEventArgs e, int x)      

50         {      

51             //画边框      

52             e.Graphics.DrawRectangle(Pens.Beige, 1, (x * 65 + 1), 

                e.ClipRectangle.Width - 3, 45);      

53             //填充选中Item背景      

54             e.Graphics.FillRectangle(Brushes.RoyalBlue, 1 + 1, (x * 65 + 1 + 1), 

                e.ClipRectangle.Width - 3 - 1, 45 - 1);      

55             //定义虚线画笔并绘边框      

56             Pen Line = new Pen(Color.Black, 1);      

57             Line.DashStyle = System.Drawing.Drawing2D.DashStyle.Dot;      

58      

59             e.Graphics.DrawRectangle(Line, 1, (x * 65 + 1), 

                e.ClipRectangle.Width - 3, 45);      

60             //画文字      

61             e.Graphics.DrawString(Items[x].ToString(), Font, Brushes.SkyBlue,

                 65, (x * 65) + 8);      

62      

63         }      

64     }      

65 }      

66      

  

//请高手指点。谢谢