GDI+ 小破孩动画

无聊写个动画程序，GDI+ 双缓存，无法去除背景色，不知道为什么?

知道的，麻烦告诉我一下

 1 namespace Animation
 2 {
 3     public partial class Form1 : Form
 4     {
 5         private Rectangle drawArea;
 6         private Bitmap currentShape;
 7         private static Graphics buffScreenGraphics, onScreenGraphics;
 8         private static int currentShapeIndex = 0;
 9         private static Bitmap buffScreenBitmap;
10 
11         public Form1()
12         {
13             InitializeComponent();
14             Init();
15         }
16 
17         private void Init()
18         {
19             this.Visible = true;
20             drawArea = new Rectangle(0, 0, 150, 130);
21             onScreenGraphics = this.CreateGraphics();
22             buffScreenBitmap = new Bitmap(drawArea.Width, drawArea.Height);
23             buffScreenGraphics = Graphics.FromImage(buffScreenBitmap);
24             buffScreenGraphics.Clear(Color.Green);
25 
26             SpriteList.Instance.LoadSprites();
27 
28             currentShape = SpriteList.Instance.Sprites[currentShapeIndex];
29             buffScreenGraphics.DrawImage(currentShape,0,0,currentShape.Width,currentShape.Height);
30         }
31 
32         protected override void  OnPaint(PaintEventArgs e)
33         {
34             onScreenGraphics.DrawImage(buffScreenBitmap, drawArea);
35              base.OnPaint(e);
36         }
37 
38         private void ReDraw()
39         {
40             onScreenGraphics.DrawImage(buffScreenBitmap, drawArea);
41         }
42 
43         private void DoNextShape()
44         {
45             currentShapeIndex = currentShapeIndex == 7 ? 0 : currentShapeIndex + 1;
46             buffScreenBitmap = SpriteList.Instance.Sprites[currentShapeIndex];
47         }
48 
49         private void timer1_Tick(object sender, EventArgs e)
50         {
51             DoNextShape();
52             ReDraw();
53             this.Left -= 10;
54              if (this.Left < -this.Width)
55                  this.Left = Screen.PrimaryScreen.Bounds.Width;
56         }
57 
58         private void Form1_KeyPress(object sender, KeyPressEventArgs e)
59         {
60              if (e.KeyChar == 27)
61                  this.Dispose();
62         }
63     }
64 }

源文件