C#驗證碼的建立和使用
阿新 • • 發佈：2018-12-18
先新增一個驗證碼類ValidateCode
using System; using System.Drawing; using System.Drawing.Drawing2D; using System.Drawing.Imaging; using System.IO; using System.Web; namespace 驗證碼生成和使用 { public class ValidateCode { public ValidateCode() { } /// <summary> /// 驗證碼的最大長度 /// </summary> public int MaxLength { get { return 10; } } /// <summary> /// 驗證碼的最小長度 /// </summary> public int MinLength { get { return 1; } } /// <summary> /// 生成驗證碼 /// </summary> /// <param name="length">指定驗證碼的長度</param> /// <returns></returns> public string CreateValidateCode(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 = (int)seekRand.Next(0, Int32.MaxValue - length * 10000); int[] seeks = new int[length]; for (int i = 0; i < length; i++) { beginSeek += 10000; seeks[i] = beginSeek; } //生成隨機數字 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); } //抽取隨機數字 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)); } //生成驗證碼 for (int i = 0; i < length; i++) { validateNumberStr += validateNums[i].ToString(); } return validateNumberStr; } /// <summary> /// 建立驗證碼的圖片 /// </summary> /// <param name="context">要輸出到的page物件</param> /// <param name="validateNum">驗證碼</param> public void CreateValidateGraphic(string validateCode, HttpContext context) { Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22); Graphics g = Graphics.FromImage(image); try { //生成隨機生成器 Random random = new Random(); //清空圖片背景色 g.Clear(Color.White); //畫圖片的干擾線 for (int i = 0; i < 25; 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.Silver), x1, y1, x2, y2); } Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic)); LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); g.DrawString(validateCode, font, brush, 3, 2); //畫圖片的前景干擾點 for (int i = 0; i < 100; i++) { int x = random.Next(image.Width); int y = random.Next(image.Height); image.SetPixel(x, y, Color.FromArgb(random.Next())); } //畫圖片的邊框線 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); //儲存圖片資料 MemoryStream stream = new MemoryStream(); image.Save(stream, ImageFormat.Jpeg); //輸出圖片流 context.Response.Clear(); context.Response.ContentType = "image/jpeg"; context.Response.BinaryWrite(stream.ToArray()); } finally { g.Dispose(); image.Dispose(); } } /// <summary> /// 得到驗證碼圖片的長度 /// </summary> /// <param name="validateNumLength">驗證碼的長度</param> /// <returns></returns> public static int GetImageWidth(int validateNumLength) { return (int)(validateNumLength * 12.0); } /// <summary> /// 得到驗證碼的高度 /// </summary> /// <returns></returns> public static double GetImageHeight() { return 22.5; } /// <summary> /// 建立驗證碼的圖片 /// </summary> /// <param name="containsPage">要輸出到的page物件</param> /// <param name="validateNum">驗證碼</param> public byte[] CreateValidateGraphic(string validateCode) { Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22); Graphics g = Graphics.FromImage(image); try { //生成隨機生成器 Random random = new Random(); //清空圖片背景色 g.Clear(Color.White); //畫圖片的干擾線 for (int i = 0; i < 25; 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.Silver), x1, y1, x2, y2); } Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic)); LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); g.DrawString(validateCode, font, brush, 3, 2); //畫圖片的前景干擾點 for (int i = 0; i < 100; i++) { int x = random.Next(image.Width); int y = random.Next(image.Height); image.SetPixel(x, y, Color.FromArgb(random.Next())); } //畫圖片的邊框線 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); //儲存圖片資料 MemoryStream stream = new MemoryStream(); image.Save(stream, ImageFormat.Jpeg); //輸出圖片流 return stream.ToArray(); } finally { g.Dispose(); image.Dispose(); } } } }
注意一點是，需要引用名稱空間：
using System.Drawing; using System.Drawing.Drawing2D; using System.Drawing.Imaging; using System.IO; using System.Web;------這個需要先在新增引用裡面的程式集裡引用到
上面是生成驗證碼的類，下面是使用驗證碼的窗體：
如下四個控制元件
private System.Windows.Forms.TextBox textBox1; private System.Windows.Forms.PictureBox pictureBox1; private System.Windows.Forms.Button btnLogin; private System.Windows.Forms.Label label1;
窗體的程式碼：
using System; using System.Drawing; using System.IO; using System.Windows.Forms; namespace 驗證碼生成和使用 { public partial class frmMain : Form { ValidateCode code = new ValidateCode();//例項化生成驗證碼的類 private string vcode = string.Empty;//宣告儲存驗證碼的字串變數 public frmMain() { InitializeComponent(); ShowCode();//呼叫生成驗證碼的方法 } //生成驗證碼的方法 private void ShowCode() { vcode = code.CreateValidateCode(4);//把生成的驗證碼賦值給變數 byte[] buffer = code.CreateValidateGraphic(vcode);//把字串轉成位元組流 pictureBox1.Image = ByteToImage(buffer);//把位元組流轉成圖片顯示在窗體中的pictureBox1控制元件 } /// <summary> /// 位元組流轉成圖片 /// </summary> /// <param name="buffer">需要轉換的位元組流</param> /// <returns>返回生成圖片</returns> private Image ByteToImage(byte[] buffer) { MemoryStream ms = new MemoryStream(buffer); return Image.FromStream(ms, true); } //登入按鈕驗證輸入的驗證碼是否正確 private void btnLogin_Click(object sender, EventArgs e) { if (textBox1.Text.Trim() != vcode) { this.Text = "驗證碼錯誤"; textBox1.Focus();//輸入錯誤，輸入框獲取焦點 } else { this.Text = "驗證碼正確"; } } //看不清換一張，重新呼叫一下生成驗證碼的方法 private void label1_Click(object sender, EventArgs e) { ShowCode(); } } }
每步都有註釋，主要點在於位元組流轉換成圖片的方法