一般驗證碼的產生方法都是相同的,主要的步驟都有兩步
第一步:隨機出一系統驗證碼的數字或字母,順便把隨機生成的數字或字母寫入Cookies 或者 Session。
第二步:用第一步隨機出來的數字或字母來合成圖片。
可以看出來驗證碼的複雜度主要是第二步來完成,你可以根據自己所要的複雜度來設定。
我們一起來看看:
第一步:隨機產生數字或字母的方法
/// <summary> /// 生成验证码的随机数 /// </summary> /// <returns>返回五位随机数</returns> private string GenerateCheckCode() { int number; char code; string checkCode = String.Empty; Random random = new Random(); for (int i = 0; i < 5; i++)//可以任意设定生成验证码的位数 { number = random.Next(); if (number % 2 == 0) code = (char)('0' + (char)(number % 10)); else code = (char)('A' + (char)(number % 26)); checkCode += code.ToString(); } Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));//写入COOKIS Session["CheckCode"] = checkCode; //写入Session,可以任意选一下 return checkCode; }
第二步:產生圖片
/// <summary> /// 生成验证码图片 /// </summary> /// <param name="checkCode"></param> private void CreateCheckCodeImage(string checkCode) { if (checkCode == null || checkCode.Trim() == String.Empty) return; Bitmap image = new Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22); Graphics g = Graphics.FromImage(image); try { //生成随机生成器 Random random = new Random(); //清空图片背景色 g.Clear(Color.White); //画图片的背景噪音线 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 System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic)); LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); g.DrawString(checkCode, font, brush, 2, 2); //画图片的前景噪音点 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())); } //画图片的边框线 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); MemoryStream ms = new MemoryStream(); image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); Response.ClearContent(); Response.ContentType = "image/Gif"; Response.BinaryWrite(ms.ToArray()); } finally {//释放对象资源 g.Dispose(); image.Dispose(); }
*完整程式
先在裡面VS2005裡面的項目裡面加上一個加一個.aspx文件,在checkCode.aspx.cs 程式碼檔案中加入以下完整程式碼
using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.Drawing; using System.IO; using System.Drawing.Drawing2D; public partial class checkCode : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { CreateCheckCodeImage(GenerateCheckCode());//调用下面两个方法; } /// <summary> /// 生成验证码的随机数 /// </summary> /// <returns>返回五位随机数</returns> private string GenerateCheckCode() { int number; char code; string checkCode = String.Empty; Random random = new Random(); for (int i = 0; i < 5; i++)//可以任意设定生成验证码的位数 { number = random.Next(); if (number % 2 == 0) code = (char)('0' + (char)(number % 10)); else code = (char)('A' + (char)(number % 26)); checkCode += code.ToString(); } Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));//写入COOKIS Session["CheckCode"] = checkCode; //写入Session,可以任意选一下 return checkCode; } /// <summary> /// 生成验证码图片 /// </summary> /// <param name="checkCode"></param> private void CreateCheckCodeImage(string checkCode) { if (checkCode == null || checkCode.Trim() == String.Empty) return; Bitmap image = new Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22); Graphics g = Graphics.FromImage(image); try { //生成随机生成器 Random random = new Random(); //清空图片背景色 g.Clear(Color.White); //画图片的背景噪音线 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 System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic)); LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); g.DrawString(checkCode, font, brush, 2, 2); //画图片的前景噪音点 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())); } //画图片的边框线 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); MemoryStream ms = new MemoryStream(); image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); Response.ClearContent(); Response.ContentType = "image/Gif"; Response.BinaryWrite(ms.ToArray()); } finally {//释放对象资源 g.Dispose(); image.Dispose(); } } }
上面產生驗證碼的頁面都做好了,我們來呼叫看看:
在你需要用到驗證碼的地方加了Image控件
這樣驗證碼就會顯示到Image控制項上面了!
顯示弄好了,當然我們要判斷一下使用者的輸入是否正確!
只要我們取得使用者輸入的值跟Cookis或Session比較就OK了
取Cookies的值Request.Cookies["CheckCode"].Value
取Session的值Session["CheckCode"].Value
取Session的值Session["CheckCode"].Value
似乎)最好先判斷Session是否空)如果不要區分大小寫的話,就把用戶輸入的值和Cookies或Session的值都轉成大寫或都小寫 附用法protected void Button1_Click(object sender, EventArgs e) { if (Request.Cookies["CheckCode"].Value == TextBox1.Text.Trim().ToString()) { Response.Write("Cookies is right"); } else { Response.Write("Cookies is wrong"); } if (Session["CheckCode"] != null) { if (Session["CheckCode"].ToString().ToUpper() == TextBox1.Text.Trim().ToString().ToUpper()) //这样写可以不能区分大小写 { Response.Write("Session is right"); } else { Response.Write("Session is wrong"); } } }以上就是本文的全部內容,教大家如何製作ASP.NET驗證碼,希望大家會喜歡。 🎜🎜更多詳解ASP.NET驗證碼的生成方法相關文章請關注PHP中文網! 🎜