Genellikle üyekayit sayfalarinda kullanilan güvenlik kodu uygulamasini verecegim kod ile kolayca kullanabilirsiniz.
Bunun için resimuretici.aspx adinda bir sayfa açin, html kismina hiçbirsey yazmaya gerek yok, codebehind kismina asagidaki kodlari yapistirin..
Imports System.Drawing.Imaging
Imports System.Drawing
Partial Class Resimuretici
Inherits System.Web.UI.Page
Private Function SifreUret() As String
Dim karakterler As Char() = {"A"c, "B"c, "C"c, "D"c, "F"c, "G"c, "H"c, "M"c, "R"c, "T"c, "V"c, "X"c, "Y"c, "Z"c, "R"c, "W"c, "S"c, "1"c, "2"c, "0"c, "3"c, "4"c, "5"c, "6"c, "7"c, "8"c, "9"c}
Dim sifre As String = ""
Dim rnd As Random = New Random
Dim i As Integer = 0
While i < 6
Dim randomindex As Integer = rnd.Next(0, karakterler.Length - 1)
Dim secilenchar As Char = karakterler(randomindex)
sifre += secilenchar.ToString
System.Math.Min(System.Threading.Interlocked.Increment(i), i - 1)
End While
Return sifre
End Function
Private Function ArkaPlanRengi() As Color
Dim renkler As Color() = {Color.Red, Color.Pink, Color.Yellow, Color.Green, Color.Blue, Color.BlanchedAlmond}
Dim rnd As Random = New Random
Return renkler(rnd.Next(0, renkler.Length - 1))
End Function
Private Sub ResimUret()
Dim password As String = SifreUret
Dim bmp As Bitmap = New Bitmap(110, 35)
Dim g As Graphics = Graphics.FromImage(bmp)
Dim mybrush As SolidBrush = New SolidBrush(ArkaPlanRengi)
g.FillRectangle(mybrush, 0, 0, bmp.Width, bmp.Height)
Dim rnd As Random = New Random
Dim karakterdizisi As Char() = password.ToCharArray
Dim sayac As Integer = 0
For Each ch As Char In karakterdizisi
Dim f As Font = New Font("verdana", 16, GraphicsUnit.Pixel)
Dim myfontbrush As SolidBrush = New SolidBrush(Color.Black)
Dim x As Integer = 5
Dim newX As Single = sayac * f.Size + x
Dim offset As Integer = rnd.Next(0, 14)
Dim p As PointF = New PointF(newX, offset)
g.DrawString(ch.ToString, f, myfontbrush, p)
System.Math.Min(System.Threading.Interlocked.Increment(sayac), sayac - 1)
Next
Session("password") = password
bmp.Save(Response.OutputStream, ImageFormat.Gif)
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
ResimUret()
End Sub
End Class
Daha sonra üyekayit sayfamiza bir Image kontrolü ekleyip src kismina resimuretici.aspx sayfasini yazmamiz yeterli...
<asp:Image ID="Image1" runat="server" ImageUrl="ResimUretici.aspx" />