using System.Drawing; //添加引用
using System.Drawing.Drawing2D;
public partial class CheckCode : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//调用自定义方法绘制验证码
CreateCheckCodeImage(GenerateCheckCode());
//Session["CheckCode"] = GenerateCheckCode();//保存到变量中，在登录是判断验证码输入是否有误
}
private string GenerateCheckCode()//绘制验证码
{
/* 样式一：该段代码生成字母+数字的验证码(4位)
*string codeStr = "1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z";
string[] strArr = codeStr.Split(',');
string checkCode = String.Empty;//创建字符串变量并初始化为空
Random random = new Random();//创建Random对象
for (int i = 0; i < 4; i++)//使用For循环生成4个数字
{
checkCode += strArr[random.Next(0, strArr.Length)];
}*/
int number;//创建整型变量
char code;//创建字符型变量
string checkCode = String.Empty;//创建字符串变量并初始化为空
Random random = new Random();//创建Random对象
for (int i = 0; i < 4; i++)//使用For循环生成4个数字
{
number = random.Next();//生成一个随机数
code = (char)('0' + (char)(number % 10));//将数字转换成为字符型
checkCode += code.ToString();
}//样式二：该段生成数字式验证码(4位)
Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));//将生成的随机数添加到Cookies中
return checkCode;//返回字符串
}
private void CreateCheckCodeImage(string checkCode)
{
//判断字符串不等于空和null
if (checkCode == null || checkCode.Trim() == String.Empty)
{
return;
}
//创建一个位图对象
Bitmap image = new Bitmap((int)Math.Ceiling((checkCode.Length * 11.5)), 22);
//创建Graphics对象
Graphics g = Graphics.FromImage(image);
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 < 2; 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, y1, x2, y2);
}
Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));
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()));
}
//画图片的边框线
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
//将图片输出到页面上
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
}
备注：using System.Drawing; //添加引用 ！！！
在登录时判断验证码是否输入正确，如下：
//if (Session["CheckCode"].ToString() != txtCode.Text.Trim())//表示区分大小写
if (!Session["CheckCode"].ToString().Equals(txtCode.Text.Trim(), StringComparison.OrdinalIgnoreCase))//表示不区分大小写
{
Response.Write("<script>alter('验证码错误！')</script>");
return;
}
另外一种样式的验证码，代码如下：
protected void Page_Load(object sender, EventArgs e)
{
string checkCode = CreateCode(4);
Session["CheckCode"] = checkCode;
CreateImage(checkCode);
}
/*产生验证码*/
public string CreateCode(int codeLength)
{
string so = "1,2,3,4,5,6,7,8,9,0,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,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[] strArr = so.Split(',');
string code = "";
Random rand = new Random();
for (int i = 0; i < codeLength; i++)
{
code += strArr[rand.Next(0, strArr.Length)];
}
return code;
}
/*产生验证图片*/
public void CreateImage(string code)
{
Bitmap image = new Bitmap(60, 20);
Graphics g = Graphics.FromImage(image);
WebColorConverter ww = new WebColorConverter();
g.Clear((Color)ww.ConvertFromString("#FAE264"));
Random random = new Random();
//画图片的背景噪音线
for (int i = 0; i < 12; 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.LightGray), x1, y1, x2, y2);
}
Font font = new Font("Arial", 15, FontStyle.Bold | FontStyle.Italic);
System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(
new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.Gray, 1.2f, true);
g.DrawString(code, font, brush, 0, 0);
//画图片的前景噪音点
//for (int i = 0; i < 10; i++)
//{
// int x = random.Next(image.Width);
// int y = random.Next(image.Height);
// image.SetPixel(x, y, Color.White);
//}
//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();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
g.Dispose();
image.Dispose();
}