C#验证码使用 - 润新知

C#验证码使用
1、C#创建验证码

1.1 创建获取验证码页面（ValidateCode.aspx）
[html] view plain copy print ?
1. <html xmlns="http://www.w3.org/1999/xhtml">
2. <head runat="server">
3. <title>获取验证码</title>
4. </head>
5. <body>
6. <form id="form1" runat="server">
7. <div>获取验证码</div>
8. </form>
9. </body>
10. </html>
```
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>获取验证码</title>
</head>
<body>
    <form id="form1" runat="server">
        <div>获取验证码</div>
    </form>
</body>
</html>
```
1.2 编写获取验证码代码（ValidateCode.aspx.cs）
[csharp] view plain copy print ?
1. /// <summary>
2. /// 验证码类型(0-字母数字混合,1-数字,2-字母)
3. /// </summary>
4. private string validateCodeType = "0";
5. /// <summary>
6. /// 验证码字符个数
7. /// </summary>
8. private int validateCodeCount = 4;
9. /// <summary>
10. /// 验证码的字符集，去掉了一些容易混淆的字符
11. /// </summary>
12. char[] character = { '2', '3', '4', '5', '6', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };
14. protected void Page_Load(object sender, EventArgs e)
15. {
16. //取消缓存
17. Response.BufferOutput = true;
18. Response.Cache.SetExpires(DateTime.Now.AddMilliseconds(-1));
19. Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache);
20. Response.AppendHeader("Pragma", "No-Cache");
21. //获取设置参数
22. if (!string.IsNullOrEmpty(Request.QueryString["validateCodeType"]))
23. {
24. validateCodeType = Request.QueryString["validateCodeType"];
25. }
26. if (!string.IsNullOrEmpty(Request.QueryString["validateCodeCount"]))
27. {
28. int.TryParse(Request.QueryString["validateCodeCount"], out validateCodeCount);
29. }
30. //生成验证码
31. this.CreateCheckCodeImage(GenerateCheckCode());
32. }
34. private string GenerateCheckCode()
35. {
36. char code ;
37. string checkCode = String.Empty;
38. System.Random random = new Random();
40. for (int i = 0; i < validateCodeCount; i++)
41. {
42. code = character[random.Next(character.Length)];
44. // 要求全为数字或字母
45. if (validateCodeType == "1")
46. {
47. if ((int)code < 48 || (int)code > 57)
48. {
49. i--;
50. continue;
51. }
52. }
53. else if (validateCodeType == "2")
54. {
55. if ((int)code < 65 || (int)code > 90)
56. {
57. i--;
58. continue;
59. }
60. }
61. checkCode += code;
62. }
64. Response.Cookies.Add(new System.Web.HttpCookie("CheckCode", checkCode));
65. this.Session["CheckCode"] = checkCode;
66. return checkCode;
67. }
69. private void CreateCheckCodeImage(string checkCode)
70. {
71. if (checkCode == null || checkCode.Trim() == String.Empty)
72. return;
74. System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length*15.0+40)), 23);
75. System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
77. try
78. {
79. //生成随机生成器
80. Random random = new Random();
82. //清空图片背景色
83. g.Clear(System.Drawing.Color.White);
85. //画图片的背景噪音线
86. for (int i = 0; i < 25; i++)
87. {
88. int x1 = random.Next(image.Width);
89. int x2 = random.Next(image.Width);
90. int y1 = random.Next(image.Height);
91. int y2 = random.Next(image.Height);
93. g.DrawLine(new System.Drawing.Pen(System.Drawing.Color.Silver), x1, y1, x2, y2);
94. }
96. System.Drawing.Font font = new System.Drawing.Font("Arial", 14, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
97. System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new System.Drawing.Rectangle(0, 0, image.Width, image.Height), System.Drawing.Color.Blue, System.Drawing.Color.DarkRed, 1.2f, true);
99. int cySpace = 16;
100. for (int i = 0; i < validateCodeCount; i++)
101. {
102. g.DrawString(checkCode.Substring(i, 1), font, brush, (i + 1) * cySpace, 1);
103. }
105. //画图片的前景噪音点
106. for (int i = 0; i < 100; i++)
107. {
108. int x = random.Next(image.Width);
109. int y = random.Next(image.Height);
111. image.SetPixel(x, y, System.Drawing.Color.FromArgb(random.Next()));
112. }
114. //画图片的边框线
115. g.DrawRectangle(new System.Drawing.Pen(System.Drawing.Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
117. System.IO.MemoryStream ms = new System.IO.MemoryStream();
118. image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
119. Response.ClearContent();
120. Response.ContentType = "image/Gif";
121. Response.BinaryWrite(ms.ToArray());
122. }
123. finally
124. {
125. g.Dispose();
126. image.Dispose();
127. }
128. }
```
/// <summary>
/// 验证码类型(0-字母数字混合,1-数字,2-字母)
/// </summary>
private string validateCodeType = "0";
/// <summary>
/// 验证码字符个数
/// </summary>
private int validateCodeCount = 4;
/// <summary>
/// 验证码的字符集，去掉了一些容易混淆的字符
/// </summary>
char[] character = { '2', '3', '4', '5', '6', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };

protected void Page_Load(object sender, EventArgs e)
{
    //取消缓存
    Response.BufferOutput = true;
    Response.Cache.SetExpires(DateTime.Now.AddMilliseconds(-1));
    Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache);
    Response.AppendHeader("Pragma", "No-Cache");
    //获取设置参数
    if (!string.IsNullOrEmpty(Request.QueryString["validateCodeType"]))
    {
        validateCodeType = Request.QueryString["validateCodeType"];
    }
    if (!string.IsNullOrEmpty(Request.QueryString["validateCodeCount"]))
    {
        int.TryParse(Request.QueryString["validateCodeCount"], out validateCodeCount);
    }
    //生成验证码
    this.CreateCheckCodeImage(GenerateCheckCode());
}

private string GenerateCheckCode()
{
    char code ;
    string checkCode = String.Empty;
    System.Random random = new Random();

    for (int i = 0; i < validateCodeCount; i++)
    {
        code = character[random.Next(character.Length)];

        // 要求全为数字或字母
        if (validateCodeType == "1")
        {
            if ((int)code < 48 || (int)code > 57)
            {
                i--;
                continue;
            }
        }
        else if (validateCodeType == "2")
        {
            if ((int)code < 65 || (int)code > 90)
            {
                i--;
                continue;
            }
        }
        checkCode += code;
    }

    Response.Cookies.Add(new System.Web.HttpCookie("CheckCode", checkCode));
    this.Session["CheckCode"] = checkCode;
    return checkCode;
}

private void CreateCheckCodeImage(string checkCode)
{
    if (checkCode == null || checkCode.Trim() == String.Empty)
        return;

    System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length*15.0+40)), 23);
    System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);

    try
    {
        //生成随机生成器
        Random random = new Random();

        //清空图片背景色
        g.Clear(System.Drawing.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 System.Drawing.Pen(System.Drawing.Color.Silver), x1, y1, x2, y2);
        }

        System.Drawing.Font font = new System.Drawing.Font("Arial", 14, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
        System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new System.Drawing.Rectangle(0, 0, image.Width, image.Height), System.Drawing.Color.Blue, System.Drawing.Color.DarkRed, 1.2f, true);

        int cySpace = 16;
        for (int i = 0; i < validateCodeCount; i++)
        {
            g.DrawString(checkCode.Substring(i, 1), font, brush, (i + 1) * cySpace, 1);
        }

        //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, System.Drawing.Color.FromArgb(random.Next()));
        }

        //画图片的边框线
        g.DrawRectangle(new System.Drawing.Pen(System.Drawing.Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

        System.IO.MemoryStream ms = new System.IO.MemoryStream();
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
        Response.ClearContent();
        Response.ContentType = "image/Gif";
        Response.BinaryWrite(ms.ToArray());
    }
    finally
    {
        g.Dispose();
        image.Dispose();
    }
}
```
2、验证码的使用

2.1 验证码的前段显示代码
[html] view plain copy print ?
1. <img src="/ValidateCode.aspx?ValidateCodeType=1&0.011150883024061309" onclick="this.src='/ValidateCode.aspx?ValidateCodeType=1&'+Math.random();" id="imgValidateCode" alt="点击刷新验证码" title="点击刷新验证码" style="cursor: pointer;">
```
<img src="/ValidateCode.aspx?ValidateCodeType=1&0.011150883024061309" onclick="this.src='/ValidateCode.aspx?ValidateCodeType=1&'+Math.random();" id="imgValidateCode" alt="点击刷新验证码" title="点击刷新验证码" style="cursor: pointer;">
```
2.2 创建验证码测试页面（ValidateTest.aspx）
[html] view plain copy print ?
1. <html xmlns="http://www.w3.org/1999/xhtml">
2. <head runat="server">
3. <title>验证码测试</title>
4. </head>
5. <body>
6. <form id="form1" runat="server">
7. <div>
8. <input runat="server" id="txtValidate" />
9. <img src="/ValidateCode.aspx?ValidateCodeType=1&0.011150883024061309" onclick="this.src='/ValidateCode.aspx?ValidateCodeType=1&'+Math.random();" id="imgValidateCode" alt="点击刷新验证码" title="点击刷新验证码" style="cursor: pointer;">
10. <asp:Button runat="server" id="btnVal" Text="提交" onclick="btnVal_Click" />
11. </div>
12. </form>
13. </body>
14. </html>
```
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>验证码测试</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <input runat="server" id="txtValidate" />
        <img src="/ValidateCode.aspx?ValidateCodeType=1&0.011150883024061309" onclick="this.src='/ValidateCode.aspx?ValidateCodeType=1&'+Math.random();" id="imgValidateCode" alt="点击刷新验证码" title="点击刷新验证码" style="cursor: pointer;">
        <asp:Button runat="server" id="btnVal" Text="提交" onclick="btnVal_Click"  />
    </div>
    </form>
</body>
</html>
```
2.3 编写验证码测试的提交代码（ValidateTest.aspx.cs）
[csharp] view plain copy print ?
1. protected void btnVal_Click(object sender, EventArgs e)
2. {
3. bool result = false; //验证结果
4. string userCode = this.txtValidate.Value; //获取用户输入的验证码
5. if (String.IsNullOrEmpty(userCode))
6. {
7. //请输入验证码
8. return;
9. }
11. string validCode = this.Session["CheckCode"] as String; //获取系统生成的验证码
12. if (!string.IsNullOrEmpty(validCode))
13. {
14. if (userCode.ToLower() == validCode.ToLower())
15. {
16. //验证成功
17. result = true;
18. }
19. else
20. {
21. //验证失败
22. result = false;
23. }
24. }
25. }
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原文地址：https://www.cnblogs.com/wwwfj/p/3207441.html