C#winform 实现登录验证码源码 最详细使用教程
需求
在登录系统的时候，我们想要实现以下效果，登录前先输入验证码，点击验证码可以刷新验证码的功能，下面就贴出实现源码
实现
首先创建Captcha.cs文件,粘贴以下代码内容（记得修改namespace），然后接着往下看
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.IO;
//生成验证码工具 定做课设，就找学长敲代码，baidu搜索学长敲代码，或者浏览器输入www.codeying.top
namespace MyAutoApp
{
class Captcha
{
#region 定做课设，就找学长敲代码，baidu搜索学长敲代码，或者浏览器输入www.codeying.top,快速定做C#课设！
private const double PI = 3.1415926535897932384626433832795;
private const double PI2 = 6.283185307179586476925286766559;
//private readonly int _wordsLen = 4;
private int _len;
private CodeType _codetype;
private readonly Single _jianju = (float)18.0;
private readonly Single _height = (float)24.0;
private string _checkCode;
#endregion
#region Public Property
public string CheckCode
{
get
{
return _checkCode;
}
}
#endregion
#region Constructors
///
/// public constructors
///
/// 验证码长度
/// 验证码类型：字母、数字、字母+ 数字
public Captcha(int len, CodeType ctype)
{
this._len = len;
this._codetype = ctype;
}
#endregion
#region Public Field
public enum CodeType { Words, Numbers, Characters, Alphas }
#endregion
#region Private Methods
private string GenerateNumbers()
{
string strOut = "";
System.Random random = new Random();
for (int i = 0; i < _len; i++)
{
string num = Convert.ToString(random.Next(10000) % 10);
strOut += num;
}
return strOut.Trim();
}
private string GenerateCharacters()
{
string strOut = "";
System.Random random = new Random();
for (int i = 0; i < _len; i++)
{
string num = Convert.ToString((char)(65 + random.Next(10000) % 26));
strOut += num;
}
return strOut.Trim();
}
//
private string GenerateAlphas()
{
string strOut = "";
string num = "";
System.Random random = new Random();
for (int i = 0; i < _len; i++)
{
if (random.Next(500) % 2 == 0)
{
num = Convert.ToString(random.Next(10000) % 10);
}
else
{
num = Convert.ToString((char)(65 + random.Next(10000) % 26));
}
strOut += num;
}
return strOut.Trim();
}
private System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
// 将位图背景填充为白色
System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);
graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);
graph.Dispose();
double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;
for (int i = 0; i < destBmp.Width; i++)
{
for (int j = 0; j < destBmp.Height; j++)
{
double dx = 0;
dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);
// 取得当前点的颜色
int nOldX = 0, nOldY = 0;
nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
nOldY = bXDir ? j : j + (int)(dy * dMultValue);
System.Drawing.Color color = srcBmp.GetPixel(i, j);
if (nOldX >= 0 && nOldX < destBmp.Width
&& nOldY >= 0 && nOldY < destBmp.Height)
{
destBmp.SetPixel(nOldX, nOldY, color);
}
}
}
return destBmp;
}
#endregion
#region Public Methods
public Stream CreateCheckCodeImage()
{
string checkCode;
switch (_codetype)
{
case CodeType.Alphas:
checkCode = GenerateAlphas();
break;
case CodeType.Numbers:
checkCode = GenerateNumbers();
break;
case CodeType.Characters:
checkCode = GenerateCharacters();
break;
default:
checkCode = GenerateAlphas();
break;
}
this._checkCode = checkCode;
MemoryStream ms = null;
//
if (checkCode == null || checkCode.Trim() == String.Empty)
return null;
Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * _jianju)), (int)_height);
Graphics g = Graphics.FromImage(image);
try
{
Random random = new Random();
g.Clear(Color.White);
// 画图片的背景噪音线
for (int i = 0; i < 18; 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.FromArgb(random.Next()), 1), x1, y1, x2, y2);
}
Font font = new System.Drawing.Font("Times New Roman", 14, System.Drawing.FontStyle.Bold);
LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
if (_codetype != CodeType.Words)
{
for (int i = 0; i < checkCode.Length; i++)
{
g.DrawString(checkCode.Substring(i, 1), font, brush, 2 + i * _jianju, 1);
}
}
else
{
g.DrawString(checkCode, font, brush, 2, 2);
}
// 画图片的前景噪音点
for (int i = 0; i < 150; i++)
{
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
// 画图片的波形滤镜效果
if (_codetype != CodeType.Words)
{
image = TwistImage(image, true, 3, 1);
}
// 画图片的边框线
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
}
finally
{
g.Dispose();
image.Dispose();
}
return ms;
}
#endregion
}
}
在登录界面添加验证码输入框captchaTb 和
PictureBox captchaPb
以下为示例代码，你可以参考我的逻辑
- 1.首先创建Captcha captcha实例
- 2.然后在窗体构造函数中调用captchaPb.Image = Bitmap.FromStream(captcha.CreateCheckCodeImage()); 这样启动页面就会有验证码显示了
- 3.在以上设计页面双击PictureBox进入二维码图片点击事件，填入代码：captchaPb.Image = Bitmap.FromStream(captcha.CreateCheckCodeImage());，使得点击二维码可以刷新内容
- 4.点击登录的时候先校验验证码
//登录窗体
public partial class LoginForm : Form
{
#region 定做课设，就找学长敲代码，baidu搜索学长敲代码，或者浏览器输入www.codeying.top,快速定做C#课设！
#endregion
/// 第一个参数表示验证码长度
/// 第二个参数表示验证码类型：字母、数字、字母+ 数字 ，我这里选择的是全数字
Captcha captcha = new Captcha(4, Captcha.CodeType.Numbers);
public LoginForm()
{
InitializeComponent();
//在窗体构造函数中调用 启动页面就会有验证码显示了
captchaPb.Image = Bitmap.FromStream(captcha.CreateCheckCodeImage());
}
//点击刷新验证码
private void captchaPb_Click(object sender, EventArgs e)
{
captchaPb.Image = Bitmap.FromStream(captcha.CreateCheckCodeImage());
}
//点击登陆按钮
private void btnLogin_Click(object sender, EventArgs e)
{
if (!captchaTb.Text.Equals(captcha.CheckCode))
{
MessageBox.Show("验证码错误！");
return;
}
....你的登录逻辑
}
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