public partial class ValidateImg : System.Web.UI.Page |
{ |
protected void Page_Load( object sender, EventArgs e) |
{ |
char [] chars = "0123456789abcdefghijklmnopqrstuvwxyz" .ToCharArray(); |
System.Random random = new Random(); |
|
string validateCode = string .Empty; |
for ( int i = 0; i < 4; i++) |
{ |
char rc = chars[random.Next(0, chars.Length)]; |
if (validateCode.IndexOf(rc) > -1) |
{ |
i--; |
continue ; |
} |
validateCode += rc; |
} |
Session[ "ValidateCode" ] = validateCode; |
CreateImage(validateCode); |
} |
|
/// <summary> |
/// 创建图片 |
/// </summary> |
/// <param name="checkCode"></param> |
private void CreateImage( string checkCode) |
{ |
int iwidth = ( int )(checkCode.Length * 11); |
System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 19); |
Graphics g = Graphics.FromImage(image); |
g.Clear(Color.White); |
//定义颜色 |
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Chocolate, Color.Brown, Color.DarkCyan, Color.Purple }; |
Random rand = new Random(); |
|
//输出不同字体和颜色的验证码字符 |
for ( int i = 0; i < checkCode.Length; i++) |
{ |
int cindex = rand.Next(7); |
Font f = new System.Drawing.Font( "Microsoft Sans Serif" , 11); |
Brush b = new System.Drawing.SolidBrush(c[cindex]); |
g.DrawString(checkCode.Substring(i, 1), f, b, (i * 10) + 1, 0, StringFormat.GenericDefault); |
} |
//画一个边框 |
g.DrawRectangle( new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1); |
|
//输出到浏览器 |
System.IO.MemoryStream ms = new System.IO.MemoryStream(); |
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); |
Response.ClearContent(); |
Response.ContentType = "image/Jpeg" ; |
Response.BinaryWrite(ms.ToArray()); |
g.Dispose(); |
image.Dispose(); |
} |
} |