Window Form 中制作验证码

Question

请问在c#窗体中如何制作验证码呢？

Answer 1

原理和web上差不多，不一样的是，你需要用图片控件显示出来；

注意：验证码的生成，验证都是要提交服务器完成。

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family as water

Answer 2

 这段代码会生成一个图片，将图片bmpBytes放到picture box中显示出来

 Bitmap bmpOut = new Bitmap(200, 50);

        Graphics g = Graphics.FromImage(bmpOut);

        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

        g.FillRectangle(Brushes.Black, 0, 0, 200, 50);

        g.DrawString(context.Session["Captcha"].ToString(), new Font("Verdana", 18), new SolidBrush(Color.White), 0, 0);

        MemoryStream ms = new MemoryStream();

        bmpOut.Save(ms, System.Drawing.Imaging.ImageFormat.Png);

        byte[] bmpBytes = ms.GetBuffer();

        bmpOut.Dispose();

        ms.Close();

其它的参考例子

https://www.c-sharpcorner.com/UploadFile/6f0898/simple-logic-to-generate-human-verification-captcha-code-in/

 Random random = new Random (); // get a random instance

            value = random.Next(10000, 99999); // get a random value between any range

            var image = new Bitmap(this.pictureBox1.Width, this.pictureBox1.Height); // Get a bitmap

            var font = new Font("TimesNewRoman", 25, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Pixel); // Get a font

            var graphics = Graphics.FromImage(image); // Get a graphics with the bitmap image

            graphics.DrawString(value.ToString (), font, Brushes.Red, new PointF(0, 0)); // Add the value in the graphics

            Pen p = new Pen(Brushes.Orange, 2.0f); // get pen width

            graphics.DrawLine(p, new PointF(0,this.pictureBox1 .Height), new Point(this.pictureBox1.Width,0)); // draw a diagonal line

            graphics.DrawLine(p, new PointF(0,0), new Point(this.pictureBox1.Width , this.pictureBox1.Height)); // draw another diagonal line

            p.Dispose(); // dispose the pen to avoid memory leak

            graphics.SmoothingMode = SmoothingMode.AntiAlias; // Smoothing the pixel

            graphics.TextRenderingHint = TextRenderingHint.AntiAlias; // Smoothing the text rendering because stem width may differ

            this.pictureBox1.Image = image; // load the image in the picturebox

https://www.codeproject.com/Articles/99148/Simple-CAPTCHA-Create-your-own-in-C

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专注于.NET ERP/CRM开发框架，C/S架构，SQL Server + ORM(LLBL Gen Pro) + Infragistics WinForms

Answer 3

请问在c#窗体中如何制作验证码呢？

Hi,

下面是一个简单的例子，你可以参考下：

    public partial class FrmVerificationCode : Form
    {
        public FrmVerificationCode()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            CodeImage(CheckCode());
        }

        private string CheckCode()
        {
            #region//生成随机数
            int number;
            char code;
            string checkcode = string.Empty;//声明变量存储随机生成的4位英文或数字
            Random random = new Random();//生成随机数
            for (int i = 0; i < 4; i++)
            {
                number = random.Next();//返回非负随机数
                if (number % 2 == 0)//判断数字是否为偶数
                    code = (char)('0' + (char)(number % 10));
                else    //如果不是偶数
                    code = (char)('A' + (char)(number % 26));
                checkcode += "" + code.ToString();   //累加字符串
            }
            return checkcode;//返回生成的字符串
            #endregion
        }
        private void CodeImage(string checkcode)
        {
            #region//生成背景图
            if (checkcode == null || checkcode.Trim() == string.Empty)
                return;
            System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkcode.Length * 12.5)), 22);//可以控制显示验证码的区域
            Graphics g = Graphics.FromImage(image);//创建Graphics对象
            try
            {
                Random random = new Random();//生成随机生成器
                g.Clear(Color.White);//清空图片背景色
                for (int i = 0; i < 5; i++)//画图片的背景噪音线
                {
                    int x1 = random.Next(image.Width);
                    int x2 = random.Next(image.Width);
                    int y1 = random.Next(image.Height);
                    int y2 = random.Next(image.Height);
                    g.DrawLine(new Pen(Color.Black), x1, y1, x2, y2);//把两点坐标用线连接起来
                }
                Font font = new Font("Arial", 12, (System.Drawing.FontStyle.Bold));//指定字体大小和样式
                g.DrawString(checkcode, font, new SolidBrush(Color.Red), 2, 2);//绘制文本字符串
                for (int i = 0; i < 150; i++)//画图片的前景噪点
                {
                    int x = random.Next(image.Width);
                    int y = random.Next(image.Height);
                    image.SetPixel(x, y, Color.FromArgb(random.Next()));//设置像素
                }
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);//绘制矩形
                this.pictureBox1.Width = image.Width;//设置pictureBox1的宽度
                this.pictureBox1.Height = image.Height;//设置pictureBox1的高度
                this.pictureBox1.BackgroundImage = image;//设置pictureBox1的背景图像
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            #endregion
        }

        private void button1_Click(object sender, EventArgs e)
        {
            CodeImage(CheckCode());
        }
    }

参考：http://blog.sina.com.cn/s/blog_6a7eff27010102fh.html

Regards,

Frankie

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