以下是我做的图文验证码的代码,运行之后,发现图片始终是裂图状态,无法正确显示验证码,各位大神看一下这是什么回事
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Drawing;
namespace PhotoVerification
{
public partial class index : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
//生成随机字符串
protected string CreateRandomNum(int NumCount)
{
string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
string[] allCharArray = allChar.Split(','); //拆分成数组
string randomNum = "";
int temp = -1; //记录上次随机数的数值,尽量避免产生几个相同的随机数
Random rand = new Random(); //声明一个Random对象
for (int i = 0; i < NumCount; i++)
{
if (temp != -1)
{
rand = new Random(i * temp * ((int)DateTime.Now.Ticks));
}
int t = rand.Next(36); //由Next()方法获取随机数
if (temp == t)
{
return CreateRandomNum(NumCount);
}
temp = t;
randomNum += allCharArray[t]; //生成随机字符串
}
return randomNum; //返回生成的随机字符串
}
//生成图片
private void CreateImage(string validateNum)
{
if (validateNum == null || validateNum.Trim() == String.Empty)
return;
//生成bitmap图像
System.Drawing.Bitmap image = new System.Drawing.Bitmap(validateNum.Length * 12 + 10, 22);
Graphics g =Graphics.FromImage(image); //设置生成图像的格式
try
{
//生成随机生成器
Random random = new Random();
//清空图片背景色
g.Clear(Color.White);
//画图片的背景噪音线
for (int i=0;i<25;i++)
{
//确定背景噪音线的位置
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.Coral), x1, y1, x2, y2); //绘制背景噪音线
}
//设置背景字体样式
Font font = new System.Drawing.Font("Arial",12,(System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
System.Drawing.Drawing2D.LinearGradientBrush brush= new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0,0,image.Width,image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
g.DrawString(validateNum, font, brush ,2, 2);
//画图片的前景噪音点
for (int i=0;i<100;i++)
{
//确定前景噪音点的位置
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x,y,Color.FromArgb(random.Next()));//绘制前景噪音点
}
//画图片的边框线
g.DrawRectangle(new Pen(Color.Silver),0,0, image.Width - 1,image.Height - 1);
System.IO.MemoryStream ms = new System.IO.MemoryStream();
//将图片保存到指定的流
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif"; //设置保存图像的格式
Response.BinaryWrite(ms.ToArray()); //执行保存图像的操作
}
finally //无论代码中是否有错误,都执行Finally中的程序代码
{
g.Dispose(); //关闭g对象
image.Dispose(); //关闭image对象
}
}
}
}