ASPX页面添加验证码
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack){
CreateCheckCodeImage(GenerateCheckCode());//调用下面两个方法;
}
}
/// <summary>
/// 生成验证码的随机数
/// </summary>
/// <returns>返回五位随机数</returns>
private string GenerateCheckCode()
{
int number;
char code;
string checkCode = String.Empty;
Random random = new Random();
for (int i = 0; i < 5; i++)//可以任意设定生成验证码的位数
{
number = random.Next();
if (number % 2 == 0)
code = (char)('0' + (char)(number % 10));
else
code = (char)('A' + (char)(number % 26));
checkCode += code.ToString();
}
Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));//写入COOKIS
Session["CheckCode"] = checkCode; //写入Session,可以任意选一下
return checkCode;
}
/// <summary>
/// 生成验证码图片
/// </summary>
/// <param name="checkCode"></param>
private void CreateCheckCodeImage(string checkCode)
{
if (checkCode == null || checkCode.Trim() == String.Empty)
return;
Bitmap image = new Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
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 < 25; 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.Silver), x1, y1, x2, y2);
}
Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
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);
MemoryStream ms = new MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
finally
{//释放对象资源
g.Dispose();
image.Dispose();
}
}
前台页面: <asp:Image ID="Image1" runat="server" src="ImgPng.aspx" style="cursor:pointer" onclick="this.src=this.src+'?'" align="middle" alt="看不清楚,点击换一张!" />
判断用session: if (Session["CheckCode"].ToString().Trim().Equals(TextBox3.Text.Trim().ToUpper()))