簡單算術驗證碼

　　 /// <summary> /// 隨機獲取運算符 /// </summary> /// <returns></returns> PRivate string GetOperator() { string OperatorArray = "+,-,×,÷"; String[] VcArray = OperatorArray.Split(','); Random random = new Random(); int iNum = random.Next(VcArray.Length); return VcArray[iNum]; }

/// <summary> /// 隨機獲取數并添加到數組 /// </summary> /// <returns></returns> private int[] GetNumber(string oper) { int[] numList = new int[2]; string OperatorArray = "1,2,3,4,5,6,7,8,9,10,12,15,18,20"; String[] VcArray = OperatorArray.Split(','); Random random = new Random(); int iNum = random.Next(VcArray.Length); int iNum1 = random.Next(VcArray.Length); if (oper == "-" || oper == "÷") { numList[0] = Convert.ToInt32(VcArray[iNum]) >= Convert.ToInt32(VcArray[iNum1]) ? Convert.ToInt32(VcArray[iNum]) : Convert.ToInt32(VcArray[iNum1]); numList[1] = Convert.ToInt32(VcArray[iNum]) < Convert.ToInt32(VcArray[iNum1]) ? Convert.ToInt32(VcArray[iNum]) : Convert.ToInt32(VcArray[iNum1]); if (oper == "÷") { //必須整除 while (numList[0] % numList[1] > 0) { iNum = random.Next(VcArray.Length); iNum1 = random.Next(VcArray.Length); numList[0] = Convert.ToInt32(VcArray[iNum]) >= Convert.ToInt32(VcArray[iNum1]) ? Convert.ToInt32(VcArray[iNum]) : Convert.ToInt32(VcArray[iNum1]); numList[1] = Convert.ToInt32(VcArray[iNum]) < Convert.ToInt32(VcArray[iNum1]) ? Convert.ToInt32(VcArray[iNum]) : Convert.ToInt32(VcArray[iNum1]); } } } else { numList[0] = Convert.ToInt32(VcArray[iNum]); numList[1] = Convert.ToInt32(VcArray[iNum1]); } return numList; }

/// <summary> /// 獲取運算結果 /// </summary> /// <param name="firstNum"></param> /// <param name="secondNum"></param> /// <param name="oper"></param> /// <returns></returns> private int GetResult(int firstNum, int secondNum, string oper) { int result = 0; switch (oper) { case "+": result = firstNum + secondNum; break; case "-": result = firstNum - secondNum; break; case "×": result = firstNum * secondNum; break; case "÷": result = firstNum / secondNum; break; } return result; }

/// <summary> /// 根據產生的隨機數生成圖象 /// </summary> /// <param name="strCode"></param> private void CreateImg(string strCode, HttpContext context) { //也可以不用指定的圖片，而是畫一個背景圖片 Bitmap bitMapImage = new Bitmap(60, 25); Graphics graphicImage = Graphics.FromImage(bitMapImage); graphicImage.FillRectangle(new SolidBrush(Color.White), 0, 0, 60, 25); //設置畫筆的輸出模式 graphicImage.SmoothingMode = SmoothingMode.HighSpeed; //添加文本字符串 graphicImage.DrawString(strCode, new Font("Arial", 15, FontStyle.Italic), SystemBrushes.WindowText, new Point(0, 0)); //畫圖片的前景噪音點 Random randomPixel = new Random(); for (int i = 0; i < 220; i++) { int x = randomPixel.Next(bitMapImage.Width); int y = randomPixel.Next(bitMapImage.Height); bitMapImage.SetPixel(x, y, Color.FromArgb(randomPixel.Next(0, 255), randomPixel.Next(0, 255), randomPixel.Next(0, 255))); } //設置圖像輸出的格式 context.Response.ContentType = "image/jpeg"; //保存數據流 bitMapImage.Save(context.Response.OutputStream, ImageFormat.Jpeg); //釋放占用的資源 graphicImage.Dispose(); bitMapImage.Dispose(); }

　　　/// <summary> /// 調用 /// </summary>

public void ProcessRequest(HttpContext context) { try { string strCode = string.Empty; var oper = GetOperator(); var firstNum = GetNumber(oper)[0]; var secondNum = GetNumber(oper)[1]; var resultNum = GetResult(firstNum, secondNum, oper); strCode = firstNum.ToString() + oper + secondNum.ToString() + "="; CreateImg(strCode, context); } catch (Exception) { throw; } }