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Dim CtrlRange As Object
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On Error Resume Next
Do
Err.Clear()
CtrlRange = Ie.Document.Body.DomElement.createControlRange()
CtrlRange.Add(Ie.Document.DomDocument.GetElementById("verifypic"))
CtrlRange.execCommand("Copy") '获取验证码
If Clipboard.ContainsData(DataFormats.Bitmap) Then
PictureBox1.Image = Clipboard.GetData(DataFormats.Bitmap) '在Picture1控件上显示
End If
If Err.Number 0 Then WaitingMS(100) ‘延时
Loop While Err.Number 0
以前找的 vbnet里也可以用
实现过程，在需要调用的页面使用image控件调用验证码生成的页面，验证码生成的页面生成验证图片且将验证信息保存至Session中，调用页面中通过Session判断用户是否输入正确。道理是这样，以下看代码：
生成验证码页面：
gif.ASPx
%@importnamespace="System"%
%@importnamespace="System.io"%
%@importnamespace="System.Drawing"%
%@importnamespace="System.Drawing.Imaging"%
scriptlanguage="VB"runat="server"
SubPage_Load(ByValSenderAsObject,ByValeAsEventArgs)
'RndNum为生成随机码的函数，
DimVNumAsString=RndNum(4)'该值为生成验证码的位数
Session("VNum")=VNum'读取Session
ValidateCode(VNum) '根据Session生成图片
EndSub
'--------------------------------------------
'生成图象验证码函数
SubValidateCode(ByValVNum)
DimImgAsSystem.Drawing.Bitmap
DimgAsGraphics
DimmsAsMemoryStream
DimgheightAsInteger=Int(Len(VNum)*14)
'gheight为图片宽度，根据字符长度自动更改图片宽度
Img=NewBitmap(gheight,24)
g=Graphics.FromImage(Img)
g.DrawString(VNum,(NewFont("Arial",12)),(NewSolidBrush(Color.Red)),3,3)'在矩形内绘制字串（字串，字体，画笔颜色，左上x.左上y）
ms=NewMemoryStream()
Img.Save(ms,ImageFormat.Png)
Response.ClearContent()'需要输出图象信息要修改HTTP头
Response.ContentType="image/Png"
Response.BinaryWrite(ms.ToArray())
g.Dispose()
Img.Dispose()
Response.End()
EndSub
'--------------------------------------------
'函数名称:RndNum
'函数参数:VCodeNum--设定返回随机字符串的位数
'函数功能:产生数字和字符混合的随机字符串
FunctionRndNum(ByValVcodeNum)
DimVcharAsString="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，W，X，Y，Z"'需要使用中文验证，可以修改这里和ValidateCode函数中的字体
DimVcArray()AsString=Split(Vchar,"，")'将字符串生成数组
DimVNumAsString=""
DimiAsByte
Fori=1ToVcodeNum
Randomize()
VNum=VNumVcArray(Int(35*Rnd()))'数组一般从0开始读取，所以这里为35*Rnd
Next
ReturnVNum
EndFunction
/script
调用页面：
demo.ASPx
scriptlanguage="VB"Runat="Server"
SubPage_Load(Senderasobject，easeventargs)
dimVNumasstring=Session("VNum")
Session.Abandon()
ViewState("VNum")=VNum
EndSub
'下面的事件代码是用来测试验证码
SubbtnSubmit_click(senderasobject，easeventargs)
'判断输入的验证码与所给是否相同
IftxtValidateCode.Text=CStr(ViewState("VNum"))Then
ensonShow.text="fontcolor='red'提示:验证通过/font"
Else
ensonShow.text="所填写的验证码与所给的不符"
EndIf
EndSub
/script
html
body
formrunat="server"
divalign="center"
tablewidth="750"
tr
tdvalign="middle"验证码:/td
!--调用验证图片生成页---
tdvalign="top"asp:Imageid="Image1"runat="server"ImageUrl="gif.aspx"//td
/tr
tr
tdvalign="top"输入验证码:/td
tdvalign="top"asp:textboxID="txtValidateCode"runat="server"TextMode="SingleLine"/fontcolor="#FF0000"size="2"*区分大小写/font/td
/tr
tr
tdcolspan="2"valign="top"align="center"asp:buttonID="btnSubmit"runat="server"Text="验证"onclick="btnSubmit_click"/
asp:labelID="ensonShow"runat="server"/
/td
/tr
/table
/div
/form
/body
/html
建一个YanzhenCard.aspx文件
保留%@ Page Language="VB" AutoEventWireup="false" CodeFile="YanzhenCard.aspx.vb" Inherits="YanzhenCard" %,其余删除
如下是代码:
Imports System.IO
Imports System.Drawing
Partial Class YanzhenCard
Inherits System.Web.UI.Page
Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
Dim VNum As String = GenerateRandom(4)
Session("VNum") = VNum
ValidateCode(VNum)
End If
End Sub
Private Sub ValidateCode(ByVal VNum As String)
Dim Gheight As Integer = CType((VNum.Length * 15), Integer)
Dim Img As Bitmap = New Bitmap(Gheight, 20) 'Bitmap是用于处理由像素数据定义的图像
Dim g As Graphics = Graphics.FromImage(Img) 'Graphics.FromImage 从指定的Image创建新的Graphics
g.DrawString(VNum, New Font("Arial", 12), New SolidBrush(Color.Red), 5, 0) 'g.DrawString()在指定位置并且用指定的Brush和Font对象绘制指定的文本字符串。
Dim ms As MemoryStream = New MemoryStream '创建其支持存储区为内存的流。
Img.Save(ms, System.Drawing.Imaging.ImageFormat.Png)
Response.ClearContent()
Response.ContentType = "image/PNG"
Response.BinaryWrite(ms.ToArray)
Response.Write(VNum)
g.Dispose()
Img.Dispose()
Response.End()
End Sub
Private Shared constant As Char() = {"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 Shared Function GenerateRandom(ByVal Length As Integer) As String
Dim newRandom As System.Text.StringBuilder = New System.Text.StringBuilder(26)
Dim rd As Random = New Random
Dim i As Integer = 0
While i Length
newRandom.Append(constant(rd.Next(26)))
System.Math.Min(System.Threading.Interlocked.Increment(i), i - 1)
End While
Return newRandom.ToString
End Function
End Class
调用方法:asp:ImageButton ID="Yanzhengma_Card" runat="server" ImageUrl="YanzhenCard.aspx" Height="20px" Width="75px" BorderColor="#6699cc" BorderStyle="Solid" BorderWidth="1px" /