protected void Page_Load(object sender, EventArgs e)
{
//获取GB2312编码页（表）
/**//**
* 生成中文验证验码所要使用的方法
* 注，生成中文验证码时要改变一下生成验证码图片的宽度
* var imageCode = new System.Drawing.Bitmap((int)Math.Ceiling((code.Length * 22.5)), 23); //定义图片的宽度和高度
**/
//var gb = Encoding.GetEncoding("gb2312");
/**/////调用函数产生4个随机中文汉字编码
//object[] bytes = CreateRegionCode(4);
/**/////根据汉字编码的字节数组解码出中文汉字
//var sbCode = new StringBuilder().Append(gb.GetString((byte[])Convert.ChangeType(bytes[0], typeof(byte[]))))
// .Append(gb.GetString((byte[])Convert.ChangeType(bytes[1], typeof(byte[]))))
// .Append(gb.GetString((byte[])Convert.ChangeType(bytes[2], typeof(byte[]))))
// .Append(gb.GetString((byte[])Convert.ChangeType(bytes[3], typeof(byte[]))));
//CreateCheckCodeImage(sbCode.ToString());
CreateCheckCodeImage(GenerateCheckCode()); //生成数字英文所要使用的方法
}
生成汉字验证码#region 生成汉字验证码
/**//// <summary>
/// 此函数在汉字编码范围内随机创建含两个元素的十六进制字节数组，每个字节数组代表一个汉字，并将四个字节数组存储在object数组中。
/// </summary>
/// <param name="strLength">代表需要产生的汉字个数</param>
/// <returns></returns>
static object[] CreateRegionCode(int strLength)
{
var rBase = new[]
{
"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"
};
var random = new Random();
var bytes = new object[strLength];
/**//*每循环一次产生一个含两个元素的十六进制字节数组，并将其放入bject数组中
每个汉字有四个区位码组成
区位码第1位和区位码第2位作为字节数组第一个元素
区位码第3位和区位码第4位作为字节数组第二个元素
*/
for (int i = 0; i < strLength; i++)
{
//区位码第1位
var r1 = random.Next(11, 14);
var str_r1 = rBase[r1].Trim();
random = new Random(r1 * unchecked((int)DateTime.Now.Ticks) + i); //更换随机数发生器的种子避免产生重复值
var r2 = 0;
if (r1 == 13)
r2 = random.Next(0, 7);
else
r2 = random.Next(0, 16);
var str_r2 = rBase[r2].Trim();
//区位码第3位
random = new Random(r2 * unchecked((int)DateTime.Now.Ticks) + i);
var r3 = random.Next(10, 16);
var str_r3 = rBase[r3].Trim();
//区位码第4位
random = new Random(r3 * unchecked((int)DateTime.Now.Ticks) + i);
var r4 = 0;
if (r3 == 10)
r4 = random.Next(1, 16);
else if (r3 == 15)
r4 = random.Next(0, 15);
else
r4 = random.Next(0, 16);
var str_r4 = rBase[r4].Trim();
var byte1 = Convert.ToByte(str_r1 + str_r2, 16);
var byte2 = Convert.ToByte(str_r3 + str_r4, 16);
//将两个字节变量存储在字节数组中
var str_r = new[] { byte1, byte2 };
//将产生的一个汉字的字节数组放入object数组中
bytes.SetValue(str_r, i);
}
return bytes;
}
#endregion
生成图片#region 生成图片
void CreateCheckCodeImage(string code)
{
var imageCode = new System.Drawing.Bitmap((int)Math.Ceiling((code.Length * 12.5)), 23); //定义图片的宽度和高度
var g = Graphics.FromImage(imageCode); //加载图片到画布上
try
{
var random = new Random();
g.Clear(Color.White); //清空图片背景色
//画图片的背景噪音线
for (int i = 0; i < 25; i++)
{
var x1 = random.Next(imageCode.Width);
var x2 = random.Next(imageCode.Width);
var y1 = random.Next(imageCode.Height);
var y2 = random.Next(imageCode.Height);
g.DrawLine(new Pen(Color.Silver), new Point(x1, y1), new Point(x2, y2));
}
var font = new System.Drawing.Font("Arial", 12F, System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic);
var brush = new System.Drawing.Drawing2D.LinearGradientBrush(
new Rectangle(0, 0, imageCode.Width, imageCode.Height),
Color.Blue, Color.DarkRed, 1.2F, true);
g.DrawString(code, font, brush, 2, 2);
//画图片的前景噪音点
for (int i = 0; i < 100; i++)
{
var x = random.Next(imageCode.Width);
var y = random.Next(imageCode.Height);
imageCode.SetPixel(x, y, Color.FromArgb(random.Next()));
}
//画图片的边框线
g.DrawRectangle(new Pen(Color.Silver), 0, 0, imageCode.Width - 1, imageCode.Height - 1);
var ms = new System.IO.MemoryStream();
imageCode.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/Jpeg";
Response.BinaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
imageCode.Dispose();
}
}
#endregion
生成数据验证码#region 生成数据验证码
private string GenerateCheckCode()
{
int number;
char code;
string checkCode = String.Empty;
var random = new Random();
for (int i = 0; i < 5; i++)
{
number = random.Next();
if (number % 2 == 0)
code = (char)('0' + (char)(number % 10));
else
code = (char)('A' + (char)(number % 26));
checkCode += code.ToString();
}
return checkCode;
}
#endregion

<form id="formCode" runat="server">
<div>
<img src="CheckCode.aspx" src="CheckCode.aspx" alt="验证码" />
</div>
</form>