ASP-Generate verification code

Final effect:

Working with files:

Verifycode.aspx

Front verifycode.aspx:

• Again Page_Load in the code, is how to generate, as well as create session.
• int length = 6; Change the number of characters in the generated verification code.
• int fontSize = ; Changes the size of the generated font, in pixels.

Using system;using system.drawing;using System.web;public partial class verifycode:system.web.ui.page{protected void        Page_Load (object sender, EventArgs e) {Validatedcode v = new Validatedcode ();            String code = V.createverifycode (); Take the Random Code v.createimageonpage (code, this.       Context);                   Output image session["Checkcode"] = code;        Create session} public class Validatedcode {#region Verification code length (default 6 captcha length) int length = 6;            public int Length {get {return length;            } set {length = value;        }} #endregion #region Captcha font size (to show distortions, default 40 pixels, you can modify it yourself) int fontSize = 50;            public int FontSize {get {return FontSize;            } set {fontSize = value; }} #endregion #regionBorder complement (default 1 pixels) int padding = 2;            public int Padding {get {return Padding;            } set {padding = value;        }} #endregion #region whether to output the dryness point (the default is not output) bool Chaos = true;            public bool Chaos {get {return Chaos;            } set {chaos = value;        }} #endregion #region the color of the output dryness point (default gray) Chaoscolor = Color.lightgray;            Public Color Chaoscolor {get {return chaoscolor;            } set {Chaoscolor = value;        }} #endregion #region custom background color (default white) color backgroundcolor = Color.White;            Public Color BackgroundColor {get {return backgroundcolor; } set            {backgroundcolor = value; }} #endregion #region custom random color array color[] colors = {color.black, color.red, Color.darkblue, Co Lor.        Green, Color.orange, Color.brown, Color.darkcyan, color.purple};            Public color[] Colors {get {return Colors;            } set {colors = value;        }} #endregion #region custom font array string[] fonts = {"Arial", "Georgia"};            Public string[] Fonts {get {return Fonts;            } set {fonts = value; }} #endregion #region a sequence of custom random code strings (delimited with commas) string codeserial = "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,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 "; public string Codeserial {get {               return codeserial;            } set {codeserial = value;        }} #endregion #region produce a waveform filter effect Private Const double PI = 3.1415926535897932384626433832795;        Private Const Double PI2 = 6.283185307179586476925286766559; <summary>//sine wave distorted picture (Edit by 51aspx.com)///</summary>//<param Nam E= "srcbmp" > Picture path </param>//<param name= "Bxdir" > If Twist is selected as true</param>//<param Name= "Nmultvalue" > Waveform amplitude multiples, the greater the degree of distortion, generally 3</param>//<param name= "Dphase" > Waveform starting phase, the value range [0-2*PI] < /param>//<returns></returns> public System.Drawing.Bitmap twistimage (Bitmap srcbmp, bo Ol Bxdir, double dmultvalue, double dphase) {System.Drawing.Bitmap destbmp = new Bitmap (Srcbmp.width, S            Rcbmp.height); Fills the bitmap background with a white System.Drawing.GraphICS graph = System.Drawing.Graphics.FromImage (destbmp); Graph.            FillRectangle (New SolidBrush (System.Drawing.Color.White), 0, 0, destbmp.width, destbmp.height); Graph.            Dispose (); Double Dbaseaxislen = Bxdir?            (double) Destbmp.height: (double) destbmp.width;                for (int i = 0, i < destbmp.width; i++) {for (int j = 0; J < Destbmp.height; J + +)                    {Double dx = 0; DX = Bxdir?                    (PI2 * (double) j)/Dbaseaxislen: (PI2 * (double) i)/Dbaseaxislen;                    DX + = Dphase;                    Double dy = math.sin (dx);                    Gets the color of the current point int noldx = 0, Noldy = 0; NOLDX = Bxdir?                    i + (int) (DY * dmultvalue): i; Noldy = Bxdir?                    J:j + (int) (DY * dmultvalue);                    System.Drawing.Color Color = Srcbmp.getpixel (i, j);   if (noldx >= 0 && noldx < destbmp.width                  && noldy >= 0 && Noldy < destbmp.height) {                    Destbmp.setpixel (NOLDX, noldy, color);        }}} return destbmp;  } #endregion #region generate a checksum picture public Bitmap Createimagecode (string code) {int Fsize            = FontSize;            int fwidth = fsize + Padding; int imagewidth = (int) (code.            Length * fwidth) + 4 + Padding * 2;            int imageheight = fsize * 2 + Padding;            System.Drawing.Bitmap image = New System.Drawing.Bitmap (imagewidth, imageheight);            Graphics g = graphics.fromimage (image);            G.clear (BackgroundColor);            Random rand = new Random (); Adds a randomly generated dry point if (this) to the background.                Chaos) {Pen pen = new Pen (chaoscolor, 0);                int c = Length * 10;               for (int i = 0; i < C; i++) {     int x = rand. Next (image.                    Width); int y = rand. Next (image.                    Height);                G.drawrectangle (pen, x, Y, 1, 1);            }} int left = 0, top = 0, Top1 = 1, top2 = 1;            int n1 = (imageheight-fontsize-padding * 2);            int n2 = N1/4;            Top1 = n2;            Top2 = n2 * 2;            Font F;            Brush b;            int CIndex, Findex; Random font and color verification code characters for (int i = 0; i < code. Length; i++) {cindex = rand.                Next (colors.length-1); Findex = Rand.                Next (fonts.length-1);                f = new System.Drawing.Font (Fonts[findex], fsize, System.Drawing.FontStyle.Bold);                b = new System.Drawing.SolidBrush (Colors[cindex]);                if (i% 2 = = 1) {top = TOP2;                } else {top = TOP1; } left = I * FWIDTH; g.DrawString (code.            Substring (i, 1), F, B, left, top); }//Draw a border border color of Color.gainsboro g.drawrectangle (new Pen (Color.gainsboro, 0), 0, 0, image. Width-1, image.            HEIGHT-1);            G.dispose ();            Generate Waveform (ADD by 51aspx.com) image = Twistimage (image, True, 8, 4);        return image;        } #endregion #region Create a good picture output to page public void Createimageonpage (string code, HttpContext context)            {System.IO.MemoryStream ms = new System.IO.MemoryStream (); Bitmap image = this.            Createimagecode (code); Image.            Save (MS, System.Drawing.Imaging.ImageFormat.Jpeg); Context.            Response.clearcontent (); Context.            Response.ContentType = "Image/jpeg"; Context. Response.BinaryWrite (Ms.            GetBuffer ()); Ms.            Close ();            ms = NULL; Image.            Dispose ();        image = NULL; #endregion #region generate random character codes        public string Createverifycode (int codelen) {if (Codelen = = 0) {Code            Len = Length;            } string[] arr = codeserial.split (', ');            String code = "";            int randvalue =-1;            Random rand = new Random (unchecked ((int) DateTime.Now.Ticks)); for (int i = 0; i < Codelen; i++) {randvalue = rand. Next (0, arr.)                LENGTH-1);            Code + = Arr[randvalue];        } return code;        } public string Createverifycode () {return createverifycode (0); } #endregion}}

　　

Background code:

original build, no modification can be.

Use:

　　

ASP-Generate verification code