.NET Core 2.0如何生成图片验证码完整实例

前言

图片验证码在我们日常开发中是必不可少会遇见的一个功能，最近工作中就遇到了这个需求，所以下面将实现的方法分享给大家，话不多说了，来一起看看详细的介绍吧。

.net core 2.0生成图片验证码

nuget包引入：zkweb.system.drawing，如下所示：

代码实例如下：verifycodehelper

using system;
using system.drawingcore;
using system.drawingcore.drawing2d;
using system.drawingcore.imaging;
using system.io;
 
namespace common.helper
{
 public sealed class verifycodehelper
 {
  #region 单例模式
  //创建私有化静态obj锁 
  private static readonly object _objlock = new object();
  //创建私有静态字段，接收类的实例化对象 
  private static verifycodehelper _verifycodehelper = null;
  //构造函数私有化 
  private verifycodehelper() { }
  //创建单利对象资源并返回 
  public static verifycodehelper getsingleobj()
  {
   if (_verifycodehelper == null)
   {
    lock (_objlock)
    {
     if (_verifycodehelper == null)
      _verifycodehelper = new verifycodehelper();
    }
   }
   return _verifycodehelper;
  }
  #endregion
 
  #region 生产验证码
  public enum verifycodetype { numberverifycode, abcverifycode, mixverifycode };
 
  /// <summary>
  /// 1.数字验证码
  /// </summary>
  /// <param name="length"></param>
  /// <returns></returns>
  private string createnumberverifycode(int length)
  {
   int[] randmembers = new int[length];
   int[] validatenums = new int[length];
   string validatenumberstr = "";
   //生成起始序列值 
   int seekseek = unchecked((int)datetime.now.ticks);
   random seekrand = new random(seekseek);
   int beginseek = seekrand.next(0, int32.maxvalue - length * 10000);
   int[] seeks = new int[length];
   for (int i = 0; i < length; i++)
   {
    beginseek += 10000;
    seeks[i] = beginseek;
   }
   //生成随机数字 
   for (int i = 0; i < length; i++)
   {
    random rand = new random(seeks[i]);
    int pownum = 1 * (int)math.pow(10, length);
    randmembers[i] = rand.next(pownum, int32.maxvalue);
   }
   //抽取随机数字 
   for (int i = 0; i < length; i++)
   {
    string numstr = randmembers[i].tostring();
    int numlength = numstr.length;
    random rand = new random();
    int numposition = rand.next(0, numlength - 1);
    validatenums[i] = int32.parse(numstr.substring(numposition, 1));
   }
   //生成验证码 
   for (int i = 0; i < length; i++)
   {
    validatenumberstr += validatenums[i].tostring();
   }
   return validatenumberstr;
  }
 
  /// <summary>
  /// 2.字母验证码
  /// </summary>
  /// <param name="length">字符长度</param>
  /// <returns>验证码字符</returns>
  private string createabcverifycode(int length)
  {
   char[] verification = new char[length];
   char[] dictionary = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
   };
   random random = new random();
   for (int i = 0; i < length; i++)
   {
    verification[i] = dictionary[random.next(dictionary.length - 1)];
   }
   return new string(verification);
  }
 
  /// <summary>
  /// 3.混合验证码
  /// </summary>
  /// <param name="length">字符长度</param>
  /// <returns>验证码字符</returns>
  private string createmixverifycode(int length)
  {
   char[] verification = new char[length];
   char[] dictionary = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    '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', 'v', 'w', 'x', 'y', 'z'
   };
   random random = new random();
   for (int i = 0; i < length; i++)
   {
    verification[i] = dictionary[random.next(dictionary.length - 1)];
   }
   return new string(verification);
  }
 
  /// <summary>
  /// 产生验证码（随机产生4-6位）
  /// </summary>
  /// <param name="type">验证码类型：数字，字符，符合</param>
  /// <returns></returns>
  public string createverifycode(verifycodetype type)
  {
   string verifycode = string.empty;
   random random = new random();
   int length = random.next(4, 6);
   switch (type)
   {
    case verifycodetype.numberverifycode:
     verifycode = getsingleobj().createnumberverifycode(length);
     break;
    case verifycodetype.abcverifycode:
     verifycode = getsingleobj().createabcverifycode(length);
     break;
    case verifycodetype.mixverifycode:
     verifycode = getsingleobj().createmixverifycode(length);
     break;
   }
   return verifycode;
  }
  #endregion
 
  #region 验证码图片
  /// <summary>
  /// 验证码图片 => bitmap
  /// </summary>
  /// <param name="verifycode">验证码</param>
  /// <param name="width">宽</param>
  /// <param name="height">高</param>
  /// <returns>bitmap</returns>
  public bitmap createbitmapbyimgverifycode(string verifycode, int width, int height)
  {
   font font = new font("arial", 14, (fontstyle.bold | fontstyle.italic));
   brush brush;
   bitmap bitmap = new bitmap(width, height);
   graphics g = graphics.fromimage(bitmap);
   sizef totalsizef = g.measurestring(verifycode, font);
   sizef curcharsizef;
   pointf startpointf = new pointf(0, (height - totalsizef.height) / 2);
   random random = new random(); //随机数产生器
   g.clear(color.white); //清空图片背景色 
   for (int i = 0; i < verifycode.length; i++)
   {
    brush = new lineargradientbrush(new point(0, 0), new point(1, 1), color.fromargb(random.next(255), random.next(255), random.next(255)), color.fromargb(random.next(255), random.next(255), random.next(255)));
    g.drawstring(verifycode[i].tostring(), font, brush, startpointf);
    curcharsizef = g.measurestring(verifycode[i].tostring(), font);
    startpointf.x += curcharsizef.width;
   }
 
   //画图片的干扰线 
   for (int i = 0; i < 10; i++)
   {
    int x1 = random.next(bitmap.width);
    int x2 = random.next(bitmap.width);
    int y1 = random.next(bitmap.height);
    int y2 = random.next(bitmap.height);
    g.drawline(new pen(color.silver), x1, y1, x2, y2);
   }
 
   //画图片的前景干扰点 
   for (int i = 0; i < 100; i++)
   {
    int x = random.next(bitmap.width);
    int y = random.next(bitmap.height);
    bitmap.setpixel(x, y, color.fromargb(random.next()));
   }
 
   g.drawrectangle(new pen(color.silver), 0, 0, bitmap.width - 1, bitmap.height - 1); //画图片的边框线 
   g.dispose();
   return bitmap;
  }
 
  /// <summary>
  /// 验证码图片 => byte[]
  /// </summary>
  /// <param name="verifycode">验证码</param>
  /// <param name="width">宽</param>
  /// <param name="height">高</param>
  /// <returns>byte[]</returns>
  public byte[] createbytebyimgverifycode(string verifycode, int width, int height)
  {
   font font = new font("arial", 14, (fontstyle.bold | fontstyle.italic));
   brush brush;
   bitmap bitmap = new bitmap(width, height);
   graphics g = graphics.fromimage(bitmap);
   sizef totalsizef = g.measurestring(verifycode, font);
   sizef curcharsizef;
   pointf startpointf = new pointf(0, (height - totalsizef.height) / 2);
   random random = new random(); //随机数产生器
   g.clear(color.white); //清空图片背景色 
   for (int i = 0; i < verifycode.length; i++)
   {
    brush = new lineargradientbrush(new point(0, 0), new point(1, 1), color.fromargb(random.next(255), random.next(255), random.next(255)), color.fromargb(random.next(255), random.next(255), random.next(255)));
    g.drawstring(verifycode[i].tostring(), font, brush, startpointf);
    curcharsizef = g.measurestring(verifycode[i].tostring(), font);
    startpointf.x += curcharsizef.width;
   }
 
   //画图片的干扰线 
   for (int i = 0; i < 10; i++)
   {
    int x1 = random.next(bitmap.width);
    int x2 = random.next(bitmap.width);
    int y1 = random.next(bitmap.height);
    int y2 = random.next(bitmap.height);
    g.drawline(new pen(color.silver), x1, y1, x2, y2);
   }
 
   //画图片的前景干扰点 
   for (int i = 0; i < 100; i++)
   {
    int x = random.next(bitmap.width);
    int y = random.next(bitmap.height);
    bitmap.setpixel(x, y, color.fromargb(random.next()));
   }
 
   g.drawrectangle(new pen(color.silver), 0, 0, bitmap.width - 1, bitmap.height - 1); //画图片的边框线 
   g.dispose();
 
   //保存图片数据 
   memorystream stream = new memorystream();
   bitmap.save(stream, imageformat.jpeg);
   //输出图片流 
   return stream.toarray();
 
  }
  #endregion
 }
}

新建控制器：verifycodecontroller，

using system.drawingcore.imaging;
using system.io;
using common.helper;
using microsoft.aspnetcore.mvc;
 
namespace webapplicationapi.controllers
{
 public class verifycodecontroller : controller
 {
  public iactionresult index()
  {
   return view();
  }
 
  /// <summary>
  /// 数字验证码
  /// </summary>
  /// <returns></returns>
  public filecontentresult numberverifycode()
  {
   string code = verifycodehelper.getsingleobj().createverifycode(verifycodehelper.verifycodetype.numberverifycode);
   byte[] codeimage = verifycodehelper.getsingleobj().createbytebyimgverifycode(code, 100, 40);
   return file(codeimage, @"image/jpeg");
  }
 
  /// <summary>
  /// 字母验证码
  /// </summary>
  /// <returns></returns>
  public filecontentresult abcverifycode()
  {
   string code = verifycodehelper.getsingleobj().createverifycode(verifycodehelper.verifycodetype.abcverifycode);
   var bitmap = verifycodehelper.getsingleobj().createbitmapbyimgverifycode(code, 100, 40);
   memorystream stream = new memorystream();
   bitmap.save(stream, imageformat.png);
   return file(stream.toarray(), "image/png");
  }
 
  /// <summary>
  /// 混合验证码
  /// </summary>
  /// <returns></returns>
  public filecontentresult mixverifycode()
  {
   string code = verifycodehelper.getsingleobj().createverifycode(verifycodehelper.verifycodetype.mixverifycode);
   var bitmap = verifycodehelper.getsingleobj().createbitmapbyimgverifycode(code, 100, 40);
   memorystream stream = new memorystream();
   bitmap.save(stream, imageformat.gif);
   return file(stream.toarray(), "image/gif");
  }
 
 }
}

添加页面index.cshtml，如下代码：

@{
 layout = null;
}
<!doctype html>
<html>
<head>
 <meta name="viewport" content="width=device-width" />
 <title>index</title>
</head>
<body>
 <figure>
  <h3>图片验证码</h3>
  <fieldset>
   <legend>数字验证码</legend>
   <img id="nubimg" title="数字验证码" src="/verifycode/numberverifycode?random=" alt="vcode" onclick="refresh()" style="cursor:pointer;" />
  </fieldset>
  <fieldset>
   <legend>数字验证码</legend>
   <img id="abcimg" title="字母验证码" src="/verifycode/abcverifycode" alt="vcode" onclick="this.src=this.src+'?'" style="cursor:pointer;" />
  </fieldset>
  <fieldset>
   <legend>混合验证码</legend>
   <img id="miximg" title="数字字母混合验证码" src="/verifycode/mixverifycode" alt="vcode" onclick="this.src=this.src+'?'" style="cursor:pointer;" />
  </fieldset>
 </figure>
 
 <script type="text/javascript">
  function refresh() {
   var id = document.getelementbyid("nubimg");
   var str = "/verifycode/numberverifycode?random=" + math.random();
   id.setattribute("src", str);
  }
 </script>
 
</body>
</html>

生成验证码如下所示：

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对的支持。