很多人写的博客大家看了会一知半解，不知道怎么用，应该引用什么类库或者代码不全，这样很多小白很是头疼，尤其是尝新技术更是如此。我们这边不止告诉你步骤，而且还提供开源demo。随着时间的推移，我们的demo库会日益强大请及时收藏GitHub。
1.首先你需要Nuget引用类库
Install-Package ZKWeb.System.Drawing -Version 4.0.1
2.创建公共类VerifyCodeHelper和CommonHelper
（1）CommonHelper中添加图形处理方法
#region 验证码 public static byte[] Bitmap2Byte(Bitmap bitmap) { using (MemoryStream stream = new MemoryStream()) { bitmap.Save(stream, ImageFormat.Jpeg); byte[] data = new byte[stream.Length]; stream.Seek(0, SeekOrigin.Begin); stream.Read(data, 0, Convert.ToInt32(stream.Length)); return data; } } #endregion public static string CodeJson(string code, string msg) { return "{\"code\":\"" + code + "\",\"msg\":\"" + msg + "\"}"; }
（2）VerifyCodeHelper添加图形处理方法
public 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 }; ////// 1.数字验证码 /// /// /// 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; } /// /// 2.字母验证码 /// /// 字符长度 /// 验证码字符 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); } /// /// 3.混合验证码 /// /// 字符长度 /// 验证码字符 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); } /// /// 产生验证码（随机产生4-6位） /// /// 验证码类型：数字，字符，符合 /// 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 /// /// 验证码图片 => Bitmap /// /// 验证码 /// 宽 /// 高 /// Bitmap 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; } /// /// 验证码图片 => byte[] /// /// 验证码 /// 宽 /// 高 /// byte[] 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
3.后台控制器根据请求返回相应图形数据
#region 验证码 #region 混合验证码 [HttpGet] public string MixVerifyCodeJson() { string code = VerifyCodeHelper.GetSingleObj().CreateVerifyCode(VerifyCodeHelper.VerifyCodeType.MixVerifyCode); var bitmap = VerifyCodeHelper.GetSingleObj().CreateBitmapByImgVerifyCode(code, 100, 40); byte[] imgBt = CommonHelper.Bitmap2Byte(bitmap); string uuid = Guid.NewGuid().ToString(); return CommonHelper.CodeJson(uuid, Convert.ToBase64String(imgBt)); } [HttpGet] public IActionResult 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.Png); return File(stream.ToArray(), "image/png"); } #endregion #region 数字验证码 [HttpGet] public string NumberVerifyCodeJson() { string code = VerifyCodeHelper.GetSingleObj().CreateVerifyCode(VerifyCodeHelper.VerifyCodeType.NumberVerifyCode); var bitmap = VerifyCodeHelper.GetSingleObj().CreateBitmapByImgVerifyCode(code, 100, 40); byte[] imgBt = CommonHelper.Bitmap2Byte(bitmap); string uuid = Guid.NewGuid().ToString(); return CommonHelper.CodeJson(uuid, Convert.ToBase64String(imgBt)); } [HttpGet] public IActionResult NumberVerifyCode() { string code = VerifyCodeHelper.GetSingleObj().CreateVerifyCode(VerifyCodeHelper.VerifyCodeType.NumberVerifyCode); var bitmap = VerifyCodeHelper.GetSingleObj().CreateBitmapByImgVerifyCode(code, 100, 40); MemoryStream stream = new MemoryStream(); bitmap.Save(stream, ImageFormat.Png); return File(stream.ToArray(), "image/png"); } #endregion #region 字母验证码 [HttpGet] public IActionResult 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"); } [HttpGet] public string AbcVerifyCodeJson() { string code = VerifyCodeHelper.GetSingleObj().CreateVerifyCode(VerifyCodeHelper.VerifyCodeType.AbcVerifyCode); var bitmap = VerifyCodeHelper.GetSingleObj().CreateBitmapByImgVerifyCode(code, 100, 40); byte[] imgBt = CommonHelper.Bitmap2Byte(bitmap); string uuid = Guid.NewGuid().ToString(); return CommonHelper.CodeJson(uuid, Convert.ToBase64String(imgBt)); } #endregion #endregion
4.前端请求分为直接请求文件或json图形数据并渲染至Img标签
图形数字验证码
"numImgJson" title="数字验证码Json获取" alt="vcode" style="cursor:pointer;" onclick="refreshNumJson()" /> "javascript:void(0);" onclick="refreshNumJson()">看不清，换一张
"numImg" title="数字验证码" src="/Verify/NumberVerifyCode?random=1994" alt="vcode" style="cursor:pointer;" onclick="refreshNum()" /> "javascript:void(0);" onclick="refreshNum()">看不清，换一张
图形字母验证码
"abcImgJson" title="图形字母验证码Json获取" alt="vcode" style="cursor:pointer;" onclick="refreshAbcJson()" /> "javascript:void(0);" onclick="refreshAbcJson()">看不清，换一张
"abcImg" title="图形字母验证码" src="/Verify/AbcVerifyCode?random=1994" alt="vcode" style="cursor:pointer;" onclick="refreshAbc()" /> "javascript:void(0);" onclick="refreshAbc()">看不清，换一张
图形混合验证码
"mixImgJson" title="图形混合验证码Json获取" alt="vcode" style="cursor:pointer;" onclick="refreshMixJson()" /> "javascript:void(0);" onclick="refreshMixJson()">看不清，换一张
"mixImg" title="图形混合验证码" src="/Verify/MixVerifyCode?random=1994" alt="vcode" style="cursor:pointer;" onclick="refreshMix()" /> "javascript:void(0);" onclick="refreshMix()">看不清，换一张
5.效果如图
开源地址 动动小手，点个推荐吧！
注意：我们机遇屋该项目将长期为大家提供asp.net core各种好用demo，旨在帮助.net开发者提升竞争力和开发速度，建议尽早收藏该模板集合项目。