C#教程之深入c#绘制验证码的详解

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C#教程之深入c#绘制验证码的详解

1.使用一个PictureBox空间，使用一个按钮，以刷新验证码。
2.首先定义CheckCode()方法，以生成4为英文及数字组成的字符串序列：

复制代码代码如下:

	
	private string CheckCode()

	        {

	            int number;

	            char code;

	            string checkCode = String.Empty;

	            Random random = new Random();

	            for (int i = 0; i < 4; i++)

	            {

	                number=random.Next();

	                if(number%2==0)

	                    code=(char)('0'+(char)(number%10));

	                else

	                    code=(char)('A'+(char)(number%26));

	                checkCode += " " + code.ToString();

	            }

	            return checkCode;

	        }

3.自定义CodeImage()方法，将CheckCode()方法生成的序列转化为图片并显示：

复制代码代码如下:

	
	        private void CodeImage(string checkCode)

	        {

	            if (checkCode == null || checkCode.Trim() == String.Empty)

	            {

	                return;

	            }

	            System.Drawing.Bitmap image=new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length*50.0)),50);

	            Graphics g=Graphics.FromImage(image);

	            try

	            {

	                Random random = new Random();

	                g.Clear(Color.White);

	                for (int i = 0; i < 3; i++)

	                {

	                    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);

	                }

	                Font font = new System.Drawing.Font("Arial", 30, (System.Drawing.FontStyle.Bold));

	                g.DrawString(checkCode, font, new SolidBrush(Color.Red), 2, 2);

	                for (int i = 0; i < 200; i++)

	                {

	                    int x = random.Next(image.Width);

	                    int y = random.Next(image.Height);

	                    image.SetPixel(x, y, Color.FromArgb(random.Next()));

	                }

	                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

	                this.pictureBox1.Width = image.Width;

	                this.pictureBox1.Height = image.Height;

	                this.pictureBox1.BackgroundImage = image;

	            }

	            catch

	            {

	            }

	        }

复制代码代码如下:

	
	        private void Form1_Load(object sender, EventArgs e)

	        {

	            CodeImage(CheckCode());

	        }

	        private void button1_Click(object sender, EventArgs e)

	        {

	            CodeImage(CheckCode());

	        }

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