vb.net 怎么將網(wǎng)頁驗(yàn)證碼顯示在窗體上

Dim CtrlRange As Object

創(chuàng)新互聯(lián)主營如東網(wǎng)站建設(shè)的網(wǎng)絡(luò)公司,主營網(wǎng)站建設(shè)方案,app軟件定制開發(fā),如東h5微信平臺(tái)小程序開發(fā)搭建,如東網(wǎng)站營銷推廣歡迎如東等地區(qū)企業(yè)咨詢

On Error Resume Next

Do

Err.Clear()

CtrlRange = Ie.Document.Body.DomElement.createControlRange()

CtrlRange.Add(Ie.Document.DomDocument.GetElementById("verifypic"))

CtrlRange.execCommand("Copy") '獲取驗(yàn)證碼

If Clipboard.ContainsData(DataFormats.Bitmap) Then

PictureBox1.Image = Clipboard.GetData(DataFormats.Bitmap) '在Picture1控件上顯示

End If

If Err.Number 0 Then WaitingMS(100) ‘延時(shí)

Loop While Err.Number 0

以前找的 vbnet里也可以用

asp.net vb怎樣制作圖片驗(yàn)證碼

實(shí)現(xiàn)過程，在需要調(diào)用的頁面使用image控件調(diào)用驗(yàn)證碼生成的頁面，驗(yàn)證碼生成的頁面生成驗(yàn)證圖片且將驗(yàn)證信息保存至Session中，調(diào)用頁面中通過Session判斷用戶是否輸入正確。道理是這樣，以下看代碼：

生成驗(yàn)證碼頁面：

gif.ASPx

%@importnamespace="System"%

%@importnamespace="System.io"%

%@importnamespace="System.Drawing"%

%@importnamespace="System.Drawing.Imaging"%

scriptlanguage="VB"runat="server"

SubPage_Load(ByValSenderAsObject,ByValeAsEventArgs)

'RndNum為生成隨機(jī)碼的函數(shù)，

DimVNumAsString=RndNum(4)'該值為生成驗(yàn)證碼的位數(shù)

Session("VNum")=VNum'讀取Session

ValidateCode(VNum) '根據(jù)Session生成圖片

EndSub

'--------------------------------------------

'生成圖象驗(yàn)證碼函數(shù)

SubValidateCode(ByValVNum)

DimImgAsSystem.Drawing.Bitmap

DimgAsGraphics

DimmsAsMemoryStream

DimgheightAsInteger=Int(Len(VNum)*14)

'gheight為圖片寬度，根據(jù)字符長度自動(dòng)更改圖片寬度

Img=NewBitmap(gheight,24)

g=Graphics.FromImage(Img)

g.DrawString(VNum,(NewFont("Arial",12)),(NewSolidBrush(Color.Red)),3,3)'在矩形內(nèi)繪制字串（字串，字體，畫筆顏色，左上x.左上y）

ms=NewMemoryStream()

Img.Save(ms,ImageFormat.Png)

Response.ClearContent()'需要輸出圖象信息要修改HTTP頭

Response.ContentType="image/Png"

Response.BinaryWrite(ms.ToArray())

g.Dispose()

Img.Dispose()

Response.End()

EndSub

'--------------------------------------------

'函數(shù)名稱:RndNum

'函數(shù)參數(shù):VCodeNum--設(shè)定返回隨機(jī)字符串的位數(shù)

'函數(shù)功能:產(chǎn)生數(shù)字和字符混合的隨機(jī)字符串

FunctionRndNum(ByValVcodeNum)

DimVcharAsString="0，1，2，3，4，5，6，7，8，9，A，B，C，D，E，F(xiàn)，G，H，I，J，K，L，M，N，O，P，Q，R，S，T，U，W，X，Y，Z"'需要使用中文驗(yàn)證，可以修改這里和ValidateCode函數(shù)中的字體

DimVcArray()AsString=Split(Vchar,"，")'將字符串生成數(shù)組

DimVNumAsString=""

DimiAsByte

Fori=1ToVcodeNum

Randomize()

VNum=VNumVcArray(Int(35*Rnd()))'數(shù)組一般從0開始讀取，所以這里為35*Rnd

Next

ReturnVNum

EndFunction

/script

調(diào)用頁面：

demo.ASPx

scriptlanguage="VB"Runat="Server"

SubPage_Load(Senderasobject，easeventargs)

dimVNumasstring=Session("VNum")

Session.Abandon()

ViewState("VNum")=VNum

EndSub

'下面的事件代碼是用來測試驗(yàn)證碼

SubbtnSubmit_click(senderasobject，easeventargs)

'判斷輸入的驗(yàn)證碼與所給是否相同

IftxtValidateCode.Text=CStr(ViewState("VNum"))Then

ensonShow.text="fontcolor='red'提示:驗(yàn)證通過/font"

Else

ensonShow.text="所填寫的驗(yàn)證碼與所給的不符"

EndIf

EndSub

/script

html

body

formrunat="server"

divalign="center"

tablewidth="750"

tr

tdvalign="middle"驗(yàn)證碼:/td

!--調(diào)用驗(yàn)證圖片生成頁---

tdvalign="top"asp:Imageid="Image1"runat="server"ImageUrl="gif.aspx"http://td

/tr

tr

tdvalign="top"輸入驗(yàn)證碼:/td

tdvalign="top"asp:textboxID="txtValidateCode"runat="server"TextMode="SingleLine"/fontcolor="#FF0000"size="2"*區(qū)分大小寫/font/td

/tr

tr

tdcolspan="2"valign="top"align="center"asp:buttonID="btnSubmit"runat="server"Text="驗(yàn)證"onclick="btnSubmit_click"/

asp:labelID="ensonShow"runat="server"/

/td

/tr

/table

/div

/form

/body

/html

求一個(gè)vb.net寫的驗(yàn)證碼？

建一個(gè)YanzhenCard.aspx文件

保留%@ Page Language="VB" AutoEventWireup="false" CodeFile="YanzhenCard.aspx.vb" Inherits="YanzhenCard" %,其余刪除

如下是代碼:

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是用于處理由像素?cái)?shù)據(jù)定義的圖像

Dim g As Graphics = Graphics.FromImage(Img) 'Graphics.FromImage 從指定的Image創(chuàng)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對象繪制指定的文本字符串。

Dim ms As MemoryStream = New MemoryStream '創(chuàng)建其支持存儲(chǔ)區(qū)為內(nèi)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

調(diào)用方法:asp:ImageButton ID="Yanzhengma_Card" runat="server" ImageUrl="YanzhenCard.aspx" Height="20px" Width="75px" BorderColor="#6699cc" BorderStyle="Solid" BorderWidth="1px" /