1、复制下列代码，拷贝到控制器中。
#region 生成验证码图片
// [OutputCache(Location = OutputCacheLocation.None, Duration = 0, NoStore = false)]
public ActionResult SecurityCode()
{ string oldcode = Session["SecurityCode"] as string;
string code = CreateRandomCode();
Session["SecurityCode"] = code;
return File(CreateValidateGraphic(code), "image/Jpeg");
} private byte[] CreateImage(string checkCode)
{
int iwidth = (int)(checkCode.Length * );
System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, );
Graphics g = Graphics.FromImage(image);
Font f = new System.Drawing.Font("Arial", , System.Drawing.FontStyle.Bold);
Brush b = new System.Drawing.SolidBrush(Color.White);
g.Clear(Color.Blue);
g.DrawString(checkCode, f, b, , );
Pen blackPen = new Pen(Color.Black, );
Random rand = new Random();
for (int i = ; i < ; i++)
{
int x1 = rand.Next(image.Width);
int x2 = rand.Next(image.Width);
int y1 = rand.Next(image.Height);
int y2 = rand.Next(image.Height);
g.DrawLine(new Pen(Color.Silver, ), x1, y1, x2, y2);
}
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
return ms.ToArray();
} private string CreateRandomCode(int codeCount)
{
string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,W,X,Y,Z";
string[] allCharArray = allChar.Split(',');
string randomCode = "";
int temp = -;
Random rand = new Random();
for (int i = ; i < codeCount; i++)
{
if (temp != -)
{
rand = new Random(i * temp * ((int)DateTime.Now.Ticks));
}
int t = rand.Next();
if (temp == t)
{
return CreateRandomCode(codeCount);
}
temp = t;
randomCode += allCharArray[t];
}
return randomCode;
}
/// <summary>
/// 创建验证码的图片
/// </summary>
public byte[] CreateValidateGraphic(string validateCode)
{
Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 16.0), );
Graphics g = Graphics.FromImage(image);
try
{
//生成随机生成器
Random random = new Random();
//清空图片背景色
g.Clear(Color.White);
//画图片的干扰线
for (int i = ; i < ; i++)
{
int x1 = random.Next(image.Width);
int x2 = random.Next(image.Width);
int y1 = random.Next(image.Height);
int y2 = random.Next(image.Height);
g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
}
Font font = new Font("Arial", , (FontStyle.Bold | FontStyle.Italic));
LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(, , image.Width, image.Height),
Color.Blue, Color.DarkRed, 1.2f, true);
g.DrawString(validateCode, font, brush, , );
//画图片的前景干扰点
for (int i = ; i < ; i++)
{
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
//画图片的边框线
g.DrawRectangle(new Pen(Color.Silver), , , image.Width - , image.Height - );
//保存图片数据
MemoryStream stream = new MemoryStream();
image.Save(stream, ImageFormat.Jpeg);
//输出图片流
return stream.ToArray();
}
finally
{
g.Dispose();
image.Dispose();
}
}
#endregion
2、复制以下图片标记到视图中
<img src="/控制器的名字/SecurityCode" onclick="this.src+='?new Date()'" />
3、验证方式，使用 Session["SecurityCode"] 判断填写的是否相等，txtCode自己输入的验证码。
if (Session["SecurityCode"] .ToString().ToLower() != txtCode.ToLower())
{
Response.Write("<script>alert('验证码错误')</script>");
}
else
{ }