Write login Verification code in C # (asp.net)

public class ValidateCode:System.Web.UI.Page


{





private void Page_Load (object sender, System.EventArgs e)


　　{





this. Createcheckcodeimage (Generatecheckcode ());


　　}


#region The code generated by the Web Forms Designer override


protected void OnInit (EventArgs e)


　　{


　　　　//


//CodeGen: This call is required for the ASP.net Web forms Designer.


　　　　//





InitializeComponent ();


base. OnInit (e);


　　}





///<summary>


///Designer supports the desired method-do not modify
with the Code Editor

///The contents of this method.


///</summary>


private void


InitializeComponent ()


　　{





this. Load + = new System.EventHandler (this. Page_Load);


　　}


#endregion


Private


string Generatecheckcode ()


　　{





int number;





char code;





string checkcode = String.Empty;


system.random Random = new Random ();


for (int i=0;i<5;i++)


　　　　{


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));


return checkcode;


　　}





private void Createcheckcodeimage (string checkcode)


　　{


if (Checkcode = null | | Checkcode.trim () = = String.Empty)


return;


System.Drawing.Bitmap image = new System.Drawing.Bitmap ((int) math.ceiling ((Checkcode.length * 12.5)), 22 );


Graphics g = graphics.fromimage (image);


Try


　　　　{


//generating random generators


Random Random = new Random ();


//Empty picture background color


g.clear (Color.White);


//Picture background noise line


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), (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));


System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush (New Rec Tangle (0, 0, image. Width, image. Height), Color.Blue, color.darkred, 1.2f, true);


g.drawstring (checkcode, Font, brush, 2, 2);


//Picture of the foreground noise point


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 ()));


　　　　　　}


//Picture border line


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 ());


　　　　}


finally





　　　　{


G.dispose ();


image. Dispose ();


　　　　}


　　}


}