ASP.NET中文验证码详解
汉字验证码技术:它比字母跟数字混合技术更先进。主要用过生成汉字的区位码将其转换为汉字，区位码是汉字一一对应的编码。用4为数字表示，前面两位从01到94成为区码，同理后面两位成为位码。懒得打字就贴出出要的程序，如有问题请联系我QQ:1264373.
CheckCode.aspx.cs:
CheckCode.aspx.cs:
1
public partial class _Default : System.Web.UI.Page
2
{
3
protected void Page_Load(object sender, EventArgs e)
4
{
5GraphicsImage(4); //调用方法生成四位汉字验证码
6
}
7
8private object[] CreateString(int strlength)
9{
10//定义一个数组存储汉字编码的组成元素
11string[] str = new string[16] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",
12"e", "f" };
13
14Random ran = new Random(); //定义一个随机数对象
15object[] bytes = new object[strlength];
16for (int i = 0; i < strlength; i++)
17{
18//获取区位码第一位
19int ran1 = ran.Next(11, 14);
20string str1 = str[ran1].Trim();
21
22//获取区位码第二位并防止数据重复
23ran = new Random(ran1 * unchecked((int)DateTime.Now.Ticks) + i);
24int ran2;
25if (ran1 == 13)
26{
27ran2 = ran.Next(0, 7);
28}
29else
30{
31ran2 = ran.Next(0, 16);
32}
33string str2 = str[ran2].Trim();
34
35//获取区位码第三位
36ran = new Random(ran2 * unchecked((int)DateTime.Now.Ticks) + i);
37int ran3 = ran.Next(10, 16);
38string str3 = str[ran3].Trim();
39
40//获取区位码第四位
41ran = new Random(ran3 * unchecked((int)DateTime.Now.Ticks) + i);
42int ran4;
43if (ran3 == 10)
44{
45ran4 = ran.Next(1, 16);
46}
47else if (ran3 == 15)
48{
49ran4 = ran.Next(0, 15);
50}
51else
52{
53ran4 = ran.Next(0, 16);
54}
55string str4 = str[ran4].Trim();
56
57//定义字节变量存储产生的随机汉字区位码
58byte byte1 = Convert.ToByte(str1 + str2, 16);
59byte byte2 = Convert.ToByte(str3 + str4, 16);
60
61byte[] stradd = new byte[] { byte1,byte2};
62//将产生的汉字字节放入数组
63bytes.SetValue(stradd, i);
64}
65return bytes;
66}
67
68private string GetString(int length)
69{
70Encoding gb = Encoding.GetEncoding("gb2312");
71object[] bytes = CreateString(length);
72
73//根据汉字字节解码出中文汉字
74string str1 = gb.GetString((byte[])Convert.ChangeType(bytes[0], typeof(byte[])));
75string str2 = gb.GetString((byte[])Convert.ChangeType(bytes[1], typeof(byte[])));
76string str3 = gb.GetString((byte[])Convert.ChangeType(bytes[2], typeof(byte[])));
77string str4 = gb.GetString((byte[])Convert.ChangeType(bytes[3], typeof(byte[])));
78
79string str = str1 + str2 + str3 + str4;
80Response.Cookies.Add(new HttpCookie("CheckCode", str));
81return str;
82}
83
84private void GraphicsImage(int length)
85{
86System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((GetString(length).Length *
8722.5)), 22);
88Graphics g = Graphics.FromImage(image); //创建画布
89
90try
91{
92//生成随机生成器
93Random random = new Random();
94
95//清空图片背景色
96g.Clear(Color.White);
97
98//画图片的背景噪音线
99for (int i = 0; i < 1; i++)
100{
101int x1 = random.Next(image.Width);
102int x2 = random.Next(image.Width);
103int y1 = random.Next(image.Height);
104int y2 = random.Next(image.Height);
105
106g.DrawLine(new Pen(Color.Black), x1, y1, x2, y2);
107}
108
109Font font = new System.Drawing.Font("Couriew New", 12, System.Drawing.FontStyle.Bold );
110System.Drawing.Drawing2D.LinearGradientBrush brush = new
111System.Drawing.Drawing2D.LinearGradientBrush
112(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
113g.DrawString(GetString(length), font, brush, 2, 2);
114
115//画图片的前景噪音点
116for (int i = 0; i < 50; i++)
117{
118int x = random.Next(image.Width);
119int y = random.Next(image.Height);
120
121image.SetPixel(x, y, Color.FromArgb(random.Next()));
122}
123
124//画图片的边框线
125g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
126System.IO.MemoryStream ms = new System.IO.MemoryStream();
127image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
128Response.ClearContent();
129Response.ContentType = "image/Gif";
130Response.BinaryWrite(ms.ToArray());
131}
132catch (Exception ms)
133{
134Response.Write(ms.Message);
135}
136}
137
}
138
引用文件：public partial class _Default : System.Web.UI.Page 2
{ 
3
protected void Page_Load(object sender, EventArgs e) 4
{ 
5
GraphicsImage(4); //调用方法生成四位汉字验证码 6
} 7
8
private object[] CreateString(int strlength) 9
{ 10
//定义一个数组存储汉字编码的组成元素 11
string[] str = new string[16] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", 12
"e", "f" }; 13
14
Random ran = new Random(); //定义一个随机数对象 15
object[] bytes = new object[strlength]; 16
for (int i = 0; i < strlength; i++) 17
{ 18
//获取区位码第一位 19
int ran1 = ran.Next(11, 14); 20
string str1 = str[ran1].Trim(); 21
22
//获取区位码第二位并防止数据重复 23
ran = new Random(ran1 * unchecked((int)DateTime.Now.Ticks) + i); 24
int ran2; 25
if (ran1 == 13) 26
{ 27
ran2 = ran.Next(0, 7); 28
} 29
else 30
{ 31
ran2 = ran.Next(0, 16); 32
} 33
string str2 = str[ran2].Trim(); 34
35
//获取区位码第三位 36
ran = new Random(ran2 * unchecked((int)DateTime.Now.Ticks) + i); 37
int ran3 = ran.Next(10, 16); 38
string str3 = str[ran3].Trim(); 39
40
//获取区位码第四位 41
ran = new Random(ran3 * unchecked((int)DateTime.Now.Ticks) + i); 42
int ran4; 43
if (ran3 == 10) 44
{ 45
ran4 = ran.Next(1, 16); 46
} 47
else if (ran3 == 15) 48
{ 49
ran4 = ran.Next(0, 15); 50
} 51
else 52
{ 53
ran4 = ran.Next(0, 16); 54
} 55
string str4 = str[ran4].Trim(); 56
57
//定义字节变量存储产生的随机汉字区位码 58
byte byte1 = Convert.ToByte(str1 + str2, 16); 59
byte byte2 = Convert.ToByte(str3 + str4, 16); 60
61
byte[] stradd = new byte[] { byte1,byte2}; 62
//将产生的汉字字节放入数组 63
bytes.SetValue(stradd, i); 64
} 65
return bytes; 66
} 67
68
private string GetString(int length) 69
{ 70
Encoding gb = Encoding.GetEncoding("gb2312"); 71
object[] bytes = CreateString(length); 72
73
//根据汉字字节解码出中文汉字 74
string str1 = gb.GetString((byte[])Convert.ChangeType(bytes[0], typeof(byte[]))); 75
string str2 = gb.GetString((byte[])Convert.ChangeType(bytes[1], typeof(byte[]))); 76
string str3 = gb.GetString((byte[])Convert.ChangeType(bytes[2], typeof(byte[]))); 77
string str4 = gb.GetString((byte[])Convert.ChangeType(bytes[3], typeof(byte[]))); 78
79
string str = str1 + str2 + str3 + str4; 80
Response.Cookies.Add(new HttpCookie("CheckCode", str)); 81
return str; 82
} 83
84
private void GraphicsImage(int length) 85
{ 86
System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((GetString(length).Length * 87
22.5)), 22); 88
Graphics g = Graphics.FromImage(image); //创建画布 89
90
try 91
{ 92
//生成随机生成器 93
Random random = new Random(); 94
95
//清空图片背景色 96
g.Clear(Color.White); 97
98
//画图片的背景噪音线 99
for (int i = 0; i < 1; i++) 100
{ 101
int x1 = random.Next(image.Width); 102
int x2 = random.Next(image.Width); 103
int y1 = random.Next(image.Height); 104
int y2 = random.Next(image.Height); 105
106
g.DrawLine(new Pen(Color.Black), x1, y1, x2, y2); 107
} 108
109
Font font = new System.Drawing.Font("Couriew New", 12, System.Drawing.FontStyle.Bold ); 110
System.Drawing.Drawing2D.LinearGradientBrush brush = new 111
System.Drawing.Drawing2D.LinearGradientBrush 112
(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); 113
g.DrawString(GetString(length), font, brush, 2, 2); 114
115
//画图片的前景噪音点 116
for (int i = 0; i < 50; i++) 117
{ 118
int x = random.Next(image.Width); 119
int y = random.Next(image.Height); 120
121
image.SetPixel(x, y, Color.FromArgb(random.Next())); 122
} 123
124
//画图片的边框线 125
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); 126
System.IO.MemoryStream ms = new System.IO.MemoryStream(); 127
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); 128
Response.ClearContent(); 129
Response.ContentType = "image/Gif"; 130
Response.BinaryWrite(ms.ToArray()); 131
} 132
catch (Exception ms) 133
{ 134
Response.Write(ms.Message); 135
} 136
} 137
}138
1 protected void Button1_Click(object sender, EventArgs e)
2 {
3 HttpCookie cookie = Request.Cookies["CheckCode"];
4 if (cookie.Value == this.TextBox3.Text.Trim())
5 {
6 Response.Write("<script>alert('验证码正确！')</script>");
7 }
8 else
9 {
10 Response.Write("<script>alert('验证码错误！')</script>");
11 }
12 }
protected void Button1_Click(object sender, EventArgs e)2
{3
HttpCookie cookie = Request.Cookies["CheckCode"];4
if (cookie.Value == this.TextBox3.Text.Trim())5
{6
Response.Write("<script>alert('验证码正确！')</script>");7
}8
else9
{10
Response.Write("<script>alert('验证码错误！')</script>");11
}12
}
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