Create a new page of the page ValidateCode.aspx for creating a verification code picture, its background CS file code is as follows: PageLoad
Private
Void
Page_load
Object
Sender, System.EventArgs E)
{String Checkcode = CreaterandMcode (4); session ["Checkcode"] = Checkcode; Creckcode (checkcode);
Where CreaterandMcode is a custom function, the parameter represents the number of verification code bits.
Private
String
CreaterAndomcode
int
CodeCount
{String Allchar = "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, Z "; string [] allchararray = allchar.split (','); string randomcode =" "; int temp = 1; random rand = new random (); for (int i = 0; i CREATEIMAGE is also a custom function for generating diagrams Private Void CREATEIMAGE String Checkcode {Int iwidth = (int) (checkCode.Length * 11.5); System.Drawing.Bitmap image = new System.Drawing.Bitmap (iwidth, 20); Graphics g = Graphics.FromImage (image); Font f = new System. Drawing.font ("Arial", 10, System.drawing.FontStyle.bold; brush b = new system.drawing.solidbrush (color.White); //g.FillRectangle (New System.drawing.Solidbrush (Color.Blue ), 0, 0, image.width, image.Height); g.clear (color.blue); g.drawstring (Checkcode, F, B, 3, 3); Pen Blackpen = New Pen (Color.Black, 0 ); Random rand = new random (); for (int i = 0; i <5; i ) {int y = rand.next (image.height); g.drawline (Blackpen, 0, Y, Image.Width, y);} system.io.MemoryStream ms = new system.io.MemoryStream (); image.save (ms, system.drawing.Image.imageformat.jpeg); response.clearcontent (); response.contenttype = "iMA GE / JPEG "; response.binaryWrite (ms.toarray ()); g.dispose (); image.dispose ();} // g.fillRectangle (new system.drawing.solidbrush (color.blue), 0,0 Image.width, image.Height; g.clear (color.blue); Both methods can change the background color of the generated picture below the FOR cycle to generate some random horizontal lines and then write on the page that requires the verification code Enter the code:
