public interface IRandomTextGenerator

{

/// <summary>

/// Gets or sets the settings.

/// </summary>

/// <value>The settings.</value>

RandomTextGeneratorSettings Settings { get; set; }

/// <summary>

/// Generates this instance.

/// </summary>

/// <returns></returns>

string Generate();

}

/// <summary>

/// Settings for the random text generator.

/// </summary>

public class RandomTextGeneratorSettings

{

/// <summary>

/// Gets or sets the length of random charachters to generate

/// </summary>

/// <value>The length.</value>

public int Length { get; set; }

/// <summary>

/// Gets or sets the allowed chars.

/// </summary>

/// <value>The allowed chars.</value>

public string AllowedChars { get; set; }

}

 

 

 

 

 

public class RandomTextGenerator : IRandomTextGenerator

{

/// <summary>

/// Initializes a new instance of the <see cref="RandomTextGenerator"/> class.

/// </summary>

public RandomTextGenerator()

{

Settings = new RandomTextGeneratorSettings();

Settings.Length = 5;

Settings.AllowedChars = "ABCDEFGHJKLMNPRSTUVWXY3456789";

}

#region IRandomTextGenerator Members

/// <summary>

/// Gets or sets the settings.

/// </summary>

/// <value>The settings.</value>

public RandomTextGeneratorSettings Settings { get; set; }

/// <summary>

/// Generate the random text.

/// </summary>

/// <returns></returns>

public string Generate()

{

Byte[] randomBytes = new Byte[Settings.Length];

RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();

rng.GetBytes(randomBytes);

char[] chars = new char[Settings.Length];

int allowedCharCount = Settings.AllowedChars.Length;

string allowedChars = Settings.AllowedChars;

for (int i = 0; i < Settings.Length; i++)

{

chars[i] = allowedChars[(int)randomBytes[i] % allowedCharCount];

}

return new string(chars);

}

#endregion

}

 

 

 

public class CaptchaImageActionResult : ActionResult

{

public string RandomWord { get; set; }

public override void ExecuteResult(ControllerContext context)

{

System.Drawing.Bitmap bmp = new System.Drawing.Bitmap((int)Math.Ceiling((RandomWord.Length * 14.5)), 22);

Graphics graphics = Graphics.FromImage(bmp);

Random random = new Random();

graphics.Clear(Color.White);

for (int i = 0; i < 20; i++)

{

int x1 = random.Next(bmp.Width);

int x2 = random.Next(bmp.Width);

int y1 = random.Next(bmp.Height);

int y2 = random.Next(bmp.Height);

if (i / 2 == 0)

{

graphics.DrawLine(new Pen(Color.DarkCyan), x1, y1, x2, y2);

}

else

{

graphics.DrawLine(new Pen(Color.Chocolate), x1, y1, x2, y2);

}

graphics.Flush();

}

Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));

System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, bmp.Width, bmp.Height), Color.Blue, Color.DarkRed, 1.2f, true);

graphics.DrawString(RandomWord, font, brush, 2, 2);

for (int i = 0; i < 5; i++)

{

int x = random.Next(bmp.Width);

int y = random.Next(bmp.Height);

bmp.SetPixel(x, y, Color.FromArgb(random.Next()));

}

graphics.DrawRectangle(new Pen(Color.Silver), 0, 0, bmp.Width - 1, bmp.Height - 1);

context.HttpContext.Response.ContentType = "image/gif";

bmp.Save(context.HttpContext.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Gif);

font.Dispose();

graphics.Dispose();

bmp.Dispose();

}

}

 

 

public CaptchaImageActionResult CaptchaImage()

{

var setting = new Framework.Utility.Captcha.RandomTextGenerator();

setting.Settings.Length = 4;

string strRandom = setting.Generate();

HttpContext.Session["RandomText"] = strRandom;

return new CaptchaImageActionResult() { RandomWord = strRandom };

}

 

 

验证码

<input value="" type="text" name="CaptchaImage" id="CaptchaImage" style="width: 60px;" />

<img style="cursor:pointer; vertical-align:middle" title="看不清楚请刷新!" id="valiCode" style="cursor: pointer;" src="/login/CaptchaImage" alt="" οnclick="this.src='/login/CaptchaImage?dt='+ new Date().getTime()"/>

<span class="Types" style="color: Red">*</span>