样式一：
验证码样式一
1 protected void Page_Load(object sender, EventArgs e)
2 {
3 if (!Page.IsPostBack)
4 {
5 this.GenImg(this.GenCode(4));
6 }
7 }
8 private string GenCode(int num)
9 {
10 string[] source ={"1","2","3","4","5","6","7","8","9",
11 "A","B","C","D","E","F","G","H","I","J","K","L","M","N",
12 "P","Q","R","S","T","U","V","W","X","Y","Z"};
13 string code = "";
14 Random rd = new Random();
15 for (int i = 0; i < num; i++)
16 {
17 code += source[rd.Next(0, source.Length)];
18 }
19 return code;
20 }
21
22 //生成图片
23 private void GenImg(string code)
24 {
25 Bitmap myPalette = new Bitmap(40, 18);
26
27 Graphics gh = Graphics.FromImage(myPalette);
28
29 Rectangle rc = new Rectangle(0, 0, 40, 18);
30
31 gh.FillRectangle(new SolidBrush(Color.Gray), rc);
32 gh.DrawString(code, new Font("宋体", 12), new SolidBrush(Color.White), rc);
33
34 myPalette.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
35
36 Session["ValidateCode"] = code;
37
38 gh.Dispose();
39 myPalette.Dispose();
40 }
样式二：
验证码样式二
1 protected void Page_Load(object sender, EventArgs e)
2 {
3 CreateCheckCodeImage(GenerateCheckCode());
4 }
5
6 //随机生成验证码
7 private string GenerateCheckCode()
8 {
9 int number;
10 char code;
11 string checkCode = String.Empty;
12 System.Random random = new Random();
13 for (int i = 0; i < 5; i++)
14 {
15 number = random.Next();
16 if (number % 2 == 0)
17 code = (char)('0' + (char)(number % 10));
18 else
19 code = (char)('A' + (char)(number % 26));
20 checkCode += code.ToString();
21 }
22 Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
23 return checkCode;
24 }
25
26 //生成验证码图片
27 private void CreateCheckCodeImage(string checkCode)
28 {
29 if (checkCode == null || checkCode.Trim() == String.Empty)
30 return;
31 System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
32 Graphics g = Graphics.FromImage(image);
33 try
34 {
35 Random random = new Random();
36 g.Clear(Color.White);
37 for (int i = 0; i < 25; i++)
38 {
39 int x1 = random.Next(image.Width);
40 int x2 = random.Next(image.Width);
41 int y1 = random.Next(image.Height);
42 int y2 = random.Next(image.Height);
43 g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
44 }
45
46 Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
47 System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
48 g.DrawString(checkCode, font, brush, 2, 2);
49 for (int i = 0; i < 100; i++)
50 {
51 int x = random.Next(image.Width);
52 int y = random.Next(image.Height);
53
54 image.SetPixel(x, y, Color.FromArgb(random.Next()));
55 }
56 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
57 System.IO.MemoryStream ms = new System.IO.MemoryStream();
58 image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
59 Response.ClearContent();
60 Response.ContentType = "image/Gif";
61 Response.BinaryWrite(ms.ToArray());
62 }
63 finally
64 {
65 g.Dispose();
66 image.Dispose();
67 }
68 }
样式三：
验证码样式三
1 private static Random rnd = new Random();
2
3 protected void Page_Load(object sender, EventArgs e)
4 {
5 int width = 60;
6 int height = 20;
7 Bitmap img = new Bitmap(width, height);
8 Graphics g = Graphics.FromImage(img);
9 Brush b;
10 b = new SolidBrush(Color.FromArgb(rnd.Next(200, 250), rnd.Next(200, 250), rnd.Next(200, 250)));
11 g.FillRectangle(b, 0, 0, width, height);
12 Pen p = new Pen(Color.FromArgb(rnd.Next(160, 200), rnd.Next(160, 200), rnd.Next(160, 200)));
13 for (int i = 0; i < 100; i++)
14 {
15 int x1 = rnd.Next(width);
16 int y1 = rnd.Next(height);
17 int x2 = x1 + rnd.Next(12);
18 int y2 = y1 + rnd.Next(12);
19 g.DrawLine(p, x1, y1, x2, y2);
20 }
21 Font f = new Font("Courier New", 16, FontStyle.Bold);
22 PointF pf;
23 StringBuilder sb = new StringBuilder();
24 for (int i = 0; i < 4; i++)
25 {
26 string s = rnd.Next(10).ToString();
27 sb.Append(s);
28 b = new SolidBrush(Color.FromArgb(rnd.Next(20, 130), rnd.Next(20, 130), rnd.Next(20, 130)));
29 pf = new PointF(13 * i, -1);
30 g.DrawString(s, f, b, pf);
31 }
32 Session["Captcha"] = sb.ToString();
33 Response.ContentType = "image/pjpeg";
34 img.Save(Response.OutputStream, ImageFormat.Jpeg);
35 b.Dispose();
36 g.Dispose();
37 img.Dispose();
38 }
样式四：
验证码样式四
1 protected void Page_Load(object sender, EventArgs e)
2 {
3 System.Random rand = new Random();
4 int len = rand.Next(4, 6);
5 char[] chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
6 System.Text.StringBuilder myStr = new System.Text.StringBuilder();
7 for (int iCount = 0; iCount < len; iCount++)
8 {
9 myStr.Append(chars[rand.Next(chars.Length)]);
10 }
11 string text = myStr.ToString();
12 this.Session["checkcode"] = text;
13 Size ImageSize = Size.Empty;
14 Font myFont = new Font("MS Sans Serif", 12);
15 using (Bitmap bmp = new Bitmap(10, 10))
16 {
17 using (Graphics g = Graphics.FromImage(bmp))
18 {
19 SizeF size = g.MeasureString(text, myFont, 5000);
20 ImageSize.Width = (int)size.Width + 1;
21 ImageSize.Height = (int)size.Height + 1;
22 }
23 }
24 using (Bitmap bmp = new Bitmap(ImageSize.Width, ImageSize.Height))
25 {
26 using (Graphics g = Graphics.FromImage(bmp))
27 {
28 g.Clear(Color.White);
29 using (StringFormat f = new StringFormat())
30 {
31 f.Alignment = StringAlignment.Near;
32 f.LineAlignment = StringAlignment.Center;
33 f.FormatFlags = StringFormatFlags.NoWrap;
34 g.DrawString(
35 text,
36 myFont,
37 Brushes.Black,
38 new RectangleF(
39 0,
40 0,
41 ImageSize.Width,
42 ImageSize.Height),
43 f);
44 }
45 }
46 int num = ImageSize.Width * ImageSize.Height * 30 / 100;
47 for (int iCount = 0; iCount < num; iCount++)
48 {
49 int x = rand.Next(ImageSize.Width);
50 int y = rand.Next(ImageSize.Height);
51 int r = rand.Next(255);
52 int g = rand.Next(255);
53 int b = rand.Next(255);
54 Color c = Color.FromArgb(r, g, b);
55 bmp.SetPixel(x, y, c);
56 }
57 System.IO.MemoryStream ms = new System.IO.MemoryStream();
58 bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
59 this.Response.ContentType = "image/png";
60 ms.WriteTo(this.Response.OutputStream);
61 ms.Close();
62 }
63 myFont.Dispose();
64 }
样式五：
验证码样式五
1 static string[] FontItems = new string[]
2 {
3 "Arial",
4 "Helvetica",
5 "Geneva",
6 "sans-serif",
7 "Verdana"
8 };
9 static Brush[] BrushItems = new Brush[]
10 {
11 Brushes.OliveDrab,
12 Brushes.ForestGreen,
13 Brushes.DarkCyan,
14 Brushes.LightSlateGray,
15 Brushes.RoyalBlue,
16 Brushes.SlateBlue,
17 Brushes.DarkViolet,
18 Brushes.MediumVioletRed,
19 Brushes.IndianRed,
20 Brushes.Firebrick,
21 Brushes.Chocolate,
22 Brushes.Peru,
23 Brushes.Goldenrod
24 };
25 static string[] BrushName = new string[]
26 {
27 "OliveDrab",
28 "ForestGreen",
29 "DarkCyan",
30 "LightSlateGray",
31 "RoyalBlue",
32 "SlateBlue",
33 "DarkViolet",
34 "MediumVioletRed",
35 "IndianRed",
36 "Firebrick",
37 "Chocolate",
38 "Peru",
39 "Goldenrod"
40 };
41 private static Color BackColor = Color.White;
42 private static Pen BorderColor = Pens.DarkGray;
43 private static int Width = 50;
44 private static int Height = 20;
45 private Random _random;
46 private string _code;
47 private int _brushNameIndex;
48
49 public void Page_Load(object sender, System.EventArgs e)
50 {
51 if (!IsPostBack)
52 {
53 // TODO : initialize
54 this._random = new Random();
55 this._code = GetRandomCode();
56
57 // TODO : use Session["code"] save the VerifyCode
58 Session["code"] = this._code;
59
60 // TODO : output Image
61 this.SetPageNoCache();
62 this.OnPaint();
63 }
64 }
65
66 //设置页面不被缓存
67 private void SetPageNoCache()
68 {
69 Response.Buffer = true;
70 Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1);
71 Response.Expires = 0;
72 Response.CacheControl = "no-cache";
73 Response.AppendHeader("Pragma", "No-Cache");
74 }
75
76 //取得一个 4 位的随机码
77 private string GetRandomCode()
78 {
79 return Guid.NewGuid().ToString().Substring(0, 4);
80 }
81
82 //随机取一个字体
83 private Font GetFont()
84 {
85 int fontIndex = _random.Next(0, FontItems.Length);
86 FontStyle fontStyle = GetFontStyle(_random.Next(0, 2));
87 return new Font(FontItems[fontIndex], 12, fontStyle);
88 }
89
90 //取一个字体的样式
91 private FontStyle GetFontStyle(int index)
92 {
93 switch (index)
94 {
95 case 0:
96 return FontStyle.Bold;
97 case 1:
98 return FontStyle.Italic;
99 default:
100 return FontStyle.Regular;
101 }
102 }
103
104 //随机取一个笔刷
105 private Brush GetBrush()
106 {
107 int brushIndex = _random.Next(0, BrushItems.Length);
108 _brushNameIndex = brushIndex;
109 return BrushItems[brushIndex];
110 }
111
112
113 //绘画事件
114 private void OnPaint()
115 {
116 Bitmap objBitmap = null;
117 Graphics g = null;
118 try
119 {
120 objBitmap = new Bitmap(Width, Height);
121 g = Graphics.FromImage(objBitmap);
122 Paint_Background(g);
123 Paint_Text(g);
124 Paint_TextStain(objBitmap);
125 Paint_Border(g);
126 objBitmap.Save(Response.OutputStream, ImageFormat.Gif);
127 Response.ContentType = "image/gif";
128 }
129 catch { }
130 finally
131 {
132 if (null != objBitmap)
133 objBitmap.Dispose();
134 if (null != g)
135 g.Dispose();
136 }
137 }
138
139
140 //绘画背景颜色
141 private void Paint_Background(Graphics g)
142 {
143 g.Clear(BackColor);
144 }
145
146 //绘画边框
147 private void Paint_Border(Graphics g)
148 {
149 g.DrawRectangle(BorderColor, 0, 0, Width - 1, Height - 1);
150 }
151
152 //绘画文字
153 private void Paint_Text(Graphics g)
154 {
155 g.DrawString(_code, GetFont(), GetBrush(), 3, 1);
156 }
157
158 //绘画文字噪音点
159 private void Paint_TextStain(Bitmap b)
160 {
161 for (int n = 0; n < 30; n++)
162 {
163 int x = _random.Next(Width);
164 int y = _random.Next(Height);
165 b.SetPixel(x, y, Color.FromName(BrushName[_brushNameIndex]));
166 }
167 }