C# winform登陆框验证码的实现方法
本文实例为大家分享了C# winform登陆框验证码的具体代码，供大家参考，具体内容如下
1、 新建一个简单的 windows 应用项目
在默认的 Form1 中添加如下控件：
1） Label ： text = “ 输入验证码 :”
2） TextBox ： name=” txtValidCode” 输入验证码的文本框
3） Image ： name=” picValidCode” 显示验证码的图片控件
4） Button ：单击事件进行验证码验证
2、 新建一个产生验证码的核心类，并构建其一个实例：
ValidCode validCode = new ValidCode (5,ValidCode .CodeType .Numbers)
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Drawing;
using System.Drawing.Drawing2D;
namespace BigHorseLib.Security
{
public class ValidCode
{
#region Private Fields
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
/// <summary>
/// public constructors
/// </summary>
/// <param name="len"> 验证码长度 </param>
/// <param name="ctype"> 验证码类型：字母、数字、字母+ 数字 </param>
public ValidCode(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
}
}
3、 图片加载验证码、验证码验证
// 图片加载验证码
picValidCode.Image = Bitmap .FromStream(validCode.CreateCheckCodeImage())
// 验证
if (!this .txtValidCode.Text.Equals(_validCode.CheckCode))
{
MessageBox .Show(" 请输入正确的验证码!" , this .Text);
this .txtValidCode.Focus();
return ;
}
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