c#动态产生验证码

//窗体登录事件产生验证码

//验证码的数值记录在number变量里面

//PictureBox1控件用来放验证码

using System;

using System.Collections.Generic;

using ponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Drawing.Drawing2D;

using 实体类库_Model_;

using 业务逻辑层_BLL_;

namespace course5

{

public partial class loginform : Form

{

public static string number;

public loginform()

{

InitializeComponent();

}

//产生验证字符串、、、、

private string checkcode()

{

int num; // 保存产生的随机数

char code; // 保存随机数转换的字符

string check = "";//保存验证码

Random random = new Random();//随机数产生器

for (int i = 0; i < 4; i++)

{

num = random.Next();

if (num % 2 == 0)

code = (char)('0' + (char)(num % 10));

else

code = (char)('A' + (char)(num % 26));

check += "" + code.ToString();

}

return check;

}

private void codeimage(string checkcode)

{

if (checkcode == null || checkcode == "")

return;//产生位图参数：长度高度

Bitmap image = new Bitmap((int)Math.Ceiling(checkcode.Length * 12.5), 21);

Graphics g = Graphics.FromImage(image);

try

{

Random random = new Random();

g.Clear(Color.White);//白色背景

for (int i = 0; i <=5; i++)

{//画背景的黑色线

g.DrawLine(new Pen(Color.Black), random.Next(image.Width), random.Next(image.Width), random.Next(image.Height), random.Next(image.Height));

}

for (int i = 0; i <= 3; i++)

{//画背景的红色线

g.DrawLine(new Pen(Color.Red), random.Next(image.Width), random.Next(image.Width), random.Next(image.Height), random.Next(image.Height));

}

Font font = new Font("宋体", 12);

//验证码写到图片上

for (int i = 0; i < checkcode.Length; i++)

{

SizeF f = g.MeasureString(checkcode[i].ToString(), font);

//g.TranslateTransform(0.01f, 0);

Matrix m = g.Transform;

m.Shear(0.4f, 0.0f);

g.Transform = m;

g.DrawString(checkcode[i].ToString(), font, new SolidBrush(Color.Red), (f.Width - 8) * i - 5, 2);

} for (int i = 0; i < 100; i++)

{// 画噪黑色音点

image.SetPixel(random.Next(image.Width), random.Next(image.Height), Color.Black);

}

for (int i = 0; i < 80; i++)

{// 画噪红色音点

image.SetPixel(random.Next(image.Width), random.Next(image.Height), Color.Red);

}

// 截成矩形

g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

this.pictureBox1.Height = image.Height;

this.pictureBox1.Width = image.Width;

this.pictureBox1.BackgroundImage = image;

}

catch

{

}

}

private void loginform_Load(object sender, EventArgs e)

{

//验证码

number = checkcode();

codeimage(number);

}

}

}