理解C#生成验证码的过程
作者：秋荷雨翔
这篇文章主要介绍了C#生成验证码的过程，通过实例分析C#验证码的生成原理，感兴趣的小伙伴们可以参考一下
本文实例为大家介绍了生成验证码的详细过程，供大家参考，具体内容如下
生成验证码的类：
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Text;
namespace Controllers.Core.Util
{
/// <summary>
/// 验证码
/// </summary>
public class VerifyCodeHelper : AdminBaseController
{
#region 变量
/// <summary>
/// 颜色表
/// </summary>
private static Color[] colors = new Color[]{
Color.FromArgb(220,20,60),
Color.FromArgb(128,0,128),
Color.FromArgb(65,105,225),
Color.FromArgb(70,130,180),
Color.FromArgb(46,139,87),
Color.FromArgb(184,134,11),
Color.FromArgb(255,140,0),
Color.FromArgb(139,69,19),
Color.FromArgb(0,191,255),
Color.FromArgb(95,158,160),
Color.FromArgb(255,20,147),
Color.FromArgb(255,165,0)};
/// <summary>
/// 字体表
/// </summary>
private static string[] fonts = new string[] {
"Arial",
"Verdana",
"Georgia",
"黑体" };
/// <summary>
/// 字体大小
/// </summary>
private static int fontSize = 22;
#endregion
#region 生成验证码图片
/// <summary>
/// 生成验证码图片
/// </summary>
public static Bitmap CreateVerifyCodeBmp(out string code)
{
int width = 120;
int height = 40;
Bitmap bmp = new Bitmap(width, height);
Graphics g = Graphics.FromImage(bmp);
Random rnd = new Random();
//背景色
g.FillRectangle(new SolidBrush(Color.White), new Rectangle(0, 0, width, height));
//文字
StringBuilder sbCode = new StringBuilder();
for (int i = 0; i < 4; i++)
{
string str = GetChar(rnd);
Font font = GetFont(rnd);
Color color = GetColor(rnd);
g.DrawString(str, font, new SolidBrush(color), new PointF((float)(i * width / 4.0), 0));
sbCode.Append(str);
}
code = sbCode.ToString();
//噪音线
for (int i = 0; i < 10; i++)
{
int x1 = rnd.Next(bmp.Width);
int x2 = rnd.Next(bmp.Width);
int y1 = rnd.Next(bmp.Height);
int y2 = rnd.Next(bmp.Height);
Pen p = new Pen(GetColor(rnd), 1);
g.DrawLine(p, x1, y1, x2, y2);
}
//扭曲
bmp = TwistImage(bmp, true, 3, rnd.NextDouble() * Math.PI * 2);
g = Graphics.FromImage(bmp);
//噪点
for (int i = 0; i < 100; i++)
{
int x1 = rnd.Next(bmp.Width);
int y1 = rnd.Next(bmp.Height);
Pen p = new Pen(GetColor(rnd), 1);
g.DrawRectangle(p, x1, y1, 1, 1);
}
//边框
g.DrawRectangle(new Pen(new SolidBrush(Color.FromArgb(153, 153, 153))), new Rectangle(0, 0, width - 1, height - 1));
return bmp;
}
#endregion
#region 获取随机字符
/// <summary>
/// 获取随机字符
/// </summary>
private static string GetChar(Random rnd)
{
int n = rnd.Next(0, 61);
if (n <= 9)
{
return ((char)(48 + n)).ToString();
}
else if (n <= 35)
{
return ((char)(65 + n - 10)).ToString();
}
else
{
return ((char)(97 + n - 36)).ToString();
}
}
#endregion
#region 获取随机字体
/// <summary>
/// 获取随机字体
/// </summary>
private static Font GetFont(Random rnd)
{
return new Font(fonts[rnd.Next(0, fonts.Length)], fontSize, FontStyle.Bold);
}
#endregion
#region 获取随机颜色
/// <summary>
/// 获取随机颜色
/// </summary>
private static Color GetColor(Random rnd)
{
return colors[rnd.Next(0, colors.Length)];
}
#endregion
#region 正弦曲线Wave扭曲图片
/// <summary>
/// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）
/// </summary>
/// <param name="srcBmp">图片路径</param>
/// <param name="bXDir">如果扭曲则选择为True</param>
/// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
/// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
private static System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
// 将位图背景填充为白色
System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);
graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);
graph.Dispose();
double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;
for (int i = 0; i < destBmp.Width; i++)
{
for (int j = 0; j < destBmp.Height; j++)
{
double dx = 0;
dx = bXDir ? (Math.PI * 2 * (double)j) / dBaseAxisLen : (Math.PI * 2 * (double)i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);
// 取得当前点的颜色
int nOldX = 0, nOldY = 0;
nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
nOldY = bXDir ? j : j + (int)(dy * dMultValue);
System.Drawing.Color color = srcBmp.GetPixel(i, j);
if (nOldX >= 0 && nOldX < destBmp.Width
&& nOldY >= 0 && nOldY < destBmp.Height)
{
destBmp.SetPixel(nOldX, nOldY, color);
}
}
}
return destBmp;
}
#endregion
}
}
验证码页面Action：
public ActionResult VerifyCode()
{
string code;
Bitmap bmp = VerifyCodeHelper.CreateVerifyCodeBmp(out code);
Bitmap newbmp = new Bitmap(bmp, 108, 36);
HttpContext.Session["VerifyCode"] = code;
Response.Clear();
Response.ContentType = "image/bmp";
newbmp.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Bmp);
return View();
}
说明：前台页面为空的cshtml页面，验证码的值放在Session中。
使用验证码的页面：
显示验证码的img：
<img id="verifyCode" src="" alt="验证码" style="vertical-align: middle;" />
页面加载完成后，显示验证码(注意，要加上时间戳，不然刷新页面时验证码不刷新)：
$(function () {
//刷新验证码
$("#refreshVerifyCode").click(function () {
refreshVerifyCode(); //刷新验证码
});
$("#verifyCode").click(function () {
refreshVerifyCode(); //刷新验证码
});
refreshVerifyCode();
});
刷新验证码：
//刷新验证码
function refreshVerifyCode() {
$("#verifyCode").attr("src", "VerifyCode?t=" + new Date().valueOf());
}
判断用户输入的文本是否与验证码相同的Action：
public ActionResult CheckVCode(string vcode)
{
if (HttpContext.Session["VerifyCode"].ToString().ToLower() == vcode.ToLower())
{
Dictionary<string, object> dic = new Dictionary<string, object>();
dic["ok"] = true;
return Content(JsonConvert.SerializeObject(dic));
}
else
{
Dictionary<string, object> dic = new Dictionary<string, object>();
dic["ok"] = false;
return Content(JsonConvert.SerializeObject(dic));
}
}
以上就是本文的全部内容，希望对大家学习C#生成验证码的方法有所帮助。