Asp.Net验证码2

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using System.IO;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;

public partial class user_Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string checkCode = CreateRandomCode(4);
        GetImgWithValidateCode(checkCode, 132, 35,20);
    }
    ///<summary>
    /// 生成随机字符串
    ///</summary>
    ///<param name="codeCount">字符数量</param>
    ///<returns>随机字符串</returns>
    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 = -1;
        Random rand = new Random();
        for (int i = 0; i < codeCount; i++)
        {
            if (temp != -1)
            {
                rand = new Random(i * temp * ((int)DateTime.Now.Ticks));
            }
            int t = rand.Next(35);
            if (temp == t)
            {
                return CreateRandomCode(codeCount);
            }
            temp = t;
            randomCode += allCharArray[t];
        }
        return randomCode;
    }

    ///<summary>
    /// 创建验证码图片
    ///</summary>
    ///<param name="code">字符串</param>
    ///<param name="width">宽</param>
    ///<param name="height">高</param>
    ///<param name="fontSize">字号</param>
    public void GetImgWithValidateCode(string code, int width, int height, int fontSize)
    {
        Color bgcolor = GetControllableColor(150);
        Color color = GetControllableColor(100);

        int charNum = code.Length;
        Bitmap bitMap = null;
        Graphics gph = null;
        //创建内存流 
        MemoryStream memStream = new MemoryStream();
        Random random = new Random();

        //创建位图对象
        bitMap = new Bitmap(width, height);
        //根据上面创建的位图对象创建绘图图面
        gph = Graphics.FromImage(bitMap);
        //设定验证码图片背景色
        gph.Clear(bgcolor);
        //产生随机干扰线条 
        for (int i = 0; i < 1; i++)
        {
            Pen backPen = new Pen(color, 2);
            int x = 0;
            int y = height / 2;
            int x2 = width;
            int y2 = random.Next(height);
            gph.DrawLine(backPen, x, y, x2, y2);
        }

        SolidBrush sb = new SolidBrush(color);
        PointF Cpoint1 = new PointF(5, 5);
        Random rnd1 = new Random();
        int x1 = 0, y1 = 0;
        //通过循环,绘制每个字符,
        for (int i = 0; i < code.Length; i++)
        {
            x1 = rnd1.Next(2) + ((width - 10) / code.Length) * i;
            y1 = rnd1.Next(bitMap.Height / 4);
            Cpoint1 = new PointF(x1, y1);
            Font textFont = new Font("Arial", fontSize, FontStyle.Bold);//字体随机,字号大小30,加粗

            //随机倾斜字符
            Matrix transform = gph.Transform;
            transform.Shear(Convert.ToSingle(rnd1.NextDouble() - 0.5), 0.001f);
            gph.Transform = transform;
            gph.DrawString(code.Substring(i, 1), textFont, sb, Cpoint1);
            gph.ResetTransform();
        }

        //画图片的前景噪音点
        for (int i = 0; i < 10; i++)
        {
            int x = random.Next(bitMap.Width);
            int y = random.Next(bitMap.Height);
            bitMap.SetPixel(x, y, Color.White);
        }
        //画图片的边框线
        gph.DrawRectangle(new Pen(Color.Black, 2), 0, 0, bitMap.Width - 1, bitMap.Height - 1);
        try
        {
            bitMap.Save(memStream, ImageFormat.Gif);
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
        bitMap.Dispose();
        System.Drawing.Image img = System.Drawing.Image.FromStream(memStream);

        gph.DrawImage(img, 50, 20, width, height);
        //img.Save(@"D:	est.jpg", ImageFormat.Jpeg);

        //如果是asp.net 用下面的输出图片

        System.IO.MemoryStream ms = new System.IO.MemoryStream();
        img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
        Response.ClearContent();
        Response.ContentType = "image/Jpeg";
        Response.BinaryWrite(ms.ToArray());
        gph.Dispose();
        img.Dispose();
    }

    ///<summary> 
    /// 产生一种 R,G,B 均大于 colorBase 随机颜色，以确保颜色不会过深 
    ///</summary> 
    ///<param name="colorBase">The color base.</param> 
    ///<returns>Color</returns>
    public Color GetControllableColor(int colorBase)
    {
        Color color = Color.Black;
        if (colorBase > 200)
        {
            return color;
        }
        Random random = new Random();
        color = Color.FromArgb(random.Next(56) + colorBase, random.Next(56) + colorBase, random.Next(56) + colorBase);
        return color;
    }
}

验证码效果：

还有2种验证码请看我博客

http://www.cnblogs.com/webapi/p/5725576.html

http://www.cnblogs.com/webapi/p/5726498.html