图形验证码
新建一个.cs文件用来写生成图形验证码的方法，返回一个MemoryStream的参数。在Default.aspx中接收输出就可以了。
1.下面是.cs的代码
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
/// <summary>
///BitmapImage 的摘要说明
/// </summary>
public class BitmapImage
{
public static MemoryStream ImageCheck()
{
Random random = new Random();
//随机产生4位随机数
string checkCode = random.Next(1000, 9999).ToString();
//Bitmap是用来指定初始化时文本的大小
Bitmap image = new Bitmap((int)Math.Ceiling((checkCode.Length * 20.5)), 22);
Graphics g = Graphics.FromImage(image);
try
{
g.Clear(Color.White);//清空图片背景色
//画图片的背景噪音线这里是4条线
for (int i = 0; i < 4; 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.Black), x1, x2, y1, y2);
}
Font font = new Font("Arial", 12, FontStyle.Bold);
//设置颜色，起始位置等参数
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()));
}
//画图片噪音线
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
MemoryStream ms = new MemoryStream();
image.Save(ms, ImageFormat.Gif);
return ms;
}
finally
{
g.Dispose();
image.Dispose();
}
}
}
2.以下是Default.aspx.cs中的代码
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
public partial class _Default : System.Web.UI.Page
{PRotected void Page_Load(object sender, EventArgs e)
{
MemoryStream ms= BitmapImage.ImageCheck();
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
}
3.截图
[flash=500,400]http://s1.knowsky.com/20160211/gpxwta1tmwv42.png[/flash]