網路上有很多C#的Sample Code
我就放一個VB.NET的Code
首先 : 製作一支ValidateCode.aspx
=====================================================
<html xmlns=”http://www.w3.org/1999/xhtml” >
<head runat=”server”>
<title>ValidateCode</title>
</head>
<body>
<form id=”form1″ runat=”server”>
<div>
</div>
</form>
</body>
</html>
=====================================================
Imports System
Imports System.Data
Imports System.Configuration
Imports System.Collections
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Imports System.Drawing
Partial Class ValidateCode
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
‘ 5位數字的驗證碼
Dim str_ValidateCode As String = GetRandomNumberString(5)
‘ 用於驗證的Session
Session(”ValidateCode”) = str_ValidateCode
Me.CreateCheckCodeImage(str_ValidateCode)
End Sub
‘ 隨機生成數字字符串
Public Function GetRandomNumberString(ByVal int_NumberLength As Integer) As String
Dim str_Number As String = String.Empty
Dim theRandomNumber As New Random()
For int_index As Integer = 0 To int_NumberLength - 1
str_Number += theRandomNumber.[Next](10).ToString()
Next
Return str_Number
End Function
Private Sub CreateCheckCodeImage(ByVal checkCode As String)
If checkCode Is Nothing OrElse checkCode.Trim() = [String].Empty Then
Return
End If
Dim image As New System.Drawing.Bitmap(CInt(Math.Ceiling((checkCode.Length * 13.5))), 25)
Dim g As System.Drawing.Graphics = Graphics.FromImage(image)
Try
‘生成隨機生成器
Dim random As New Random()
‘清空圖片背景色
g.Clear(Color.White)
For i As Integer = 0 To 24
‘畫圖片的背景噪音線
Dim x1 As Integer = random.[Next](image.Width)
Dim x2 As Integer = random.[Next](image.Width)
Dim y1 As Integer = random.[Next](image.Height)
Dim y2 As Integer = random.[Next](image.Height)
g.DrawLine(New Pen(Color.Silver), x1, y1, x2, y2)
Next
Dim font As Font = New System.Drawing.Font(”Arial”, 14, (System.Drawing.FontStyle.Bold Or System.Drawing.FontStyle.Italic))
Dim brush As New System.Drawing.Drawing2D.LinearGradientBrush(New Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2F, True)
g.DrawString(checkCode, font, brush, 2, 2)
For i As Integer = 0 To 99
‘畫圖片的前景噪音點
Dim x As Integer = random.[Next](image.Width)
Dim y As Integer = random.[Next](image.Height)
image.SetPixel(x, y, Color.FromArgb(random.[Next]()))
Next
‘畫圖片的邊框線
g.DrawRectangle(New Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1)
Dim ms As 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()
End Try
End Sub
End Class
2.然後在要使用的頁面放上這頁來當Image來源
<asp:TextBox ID=”TextBox” runat=”server”></asp:TextBox>
<asp:Image id=”Image1″ runat=”server” ImageUrl=”ValidateCode.aspx” ImageAlign=”Middle” />
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