求一個vb.net寫的驗證碼？

建一個YanzhenCard.aspx文件

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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是用于處理由像素數(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" /

asp.net vb怎樣制作圖片驗證碼

實現(xiàn)過程，在需要調(diào)用的頁面使用image控件調(diào)用驗證碼生成的頁面，驗證碼生成的頁面生成驗證圖片且將驗證信息保存至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為生成隨機碼的函數(shù)，

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

SubbtnSubmit_click(senderasobject，easeventargs)

'判斷輸入的驗證碼與所給是否相同

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

ensonShow.text="fontcolor='red'提示:驗證通過/font"

Else

ensonShow.text="所填寫的驗證碼與所給的不符"

EndIf

EndSub

/script

html

body

formrunat="server"

divalign="center"

tablewidth="750"

tr

tdvalign="middle"驗證碼:/td

!--調(diào)用驗證圖片生成頁---

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="驗證"onclick="btnSubmit_click"/

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

/td

/tr

/table

/div

/form

/body

/html

vb.net 做出類似這樣的驗證碼 白色字體，字形扭曲

這個是可以使用api來做的。圖像處理之類的函數(shù)。

另外，還有一種方法是將所有的字符和數(shù)字做成不同的小圖片進行拼接而成的一個字符串序列；

小圖片要自己去做；效果就可以任意展現(xiàn)了。

vb.net 怎么將網(wǎng)頁驗證碼顯示在窗體上

Dim CtrlRange As Object

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

Loop While Err.Number 0

以前找的 vbnet里也可以用

VB NET 中怎樣實現(xiàn)動態(tài)驗證碼

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?Public?Class?VerifyCode

Inherits?System.Web.UI.Page

Protected?Sub?Page_Load(ByVal?sender?As?Object,?ByVal?e?As?System.EventArgs)

Session("VerifyCode")?=?MakeValidateCode()

CreateImage(Session("VerifyCode").ToString())

End?Sub

Private?Sub?CreateImage(ByVal?checkCode?As?String)

Dim?iwidth?As?Integer?=?CInt(checkCode.Length?*?12)?+?10

Dim?image?As?New?System.Drawing.Bitmap(iwidth,?25)

Dim?g?As?Graphics?=?Graphics.FromImage(image)

g.Clear(Color.White)

'定義顏色

Dim?c()?As?Color?=?{?Color.Black,?Color.Red,?Color.DarkBlue,?Color.Green,?Color.Orange,?Color.Brown,?Color.DarkCyan,?Color.Purple?}

'定義字體

Dim?font()?As?String?=?{?"Verdana",?"Microsoft?Sans?Serif",?"Comic?Sans?MS",?"Arial",?"宋體"?}

Dim?rand?As?New?Random()

'隨機輸出噪點

For?i?As?Integer?=?0?To?4

Dim?x?As?Integer?=?rand.Next(image.Width)

Dim?y?As?Integer?=?rand.Next(image.Height)

g.DrawRectangle(New?Pen(Color.LightGray,?0),?x,?y,?1,?1)

Next?i

'輸出不同字體和顏色的驗證碼字符

For?i?As?Integer?=?0?To?checkCode.Length?-?1

Dim?cindex?As?Integer?=?rand.Next(7)

Dim?findex?As?Integer?=?rand.Next(5)

Dim?f?As?Font?=?New?System.Drawing.Font("宋體",?12,?System.Drawing.FontStyle.Regular)

Dim?b?As?Brush?=?New?System.Drawing.SolidBrush(c(cindex))

Dim?ii?As?Integer?=?4

If?(i?+?1)?Mod?2?=?0?Then

ii?=?2

End?If

g.DrawString(checkCode.Substring(i,?1),?f,?b,?3?+?(i?*?12),?ii)

Next?i

'畫一個邊框

g.DrawRectangle(New?Pen(Color.Black,?0),?0,?0,?image.Width?-?1,?image.Height?-?1)

'輸出到瀏覽器

Dim?ms?As?New?System.IO.MemoryStream()

image.Save(ms,?System.Drawing.Imaging.ImageFormat.Jpeg)

Response.ClearContent()

Response.ContentType?=?"image/Jpeg"

Response.BinaryWrite(ms.ToArray())

g.Dispose()

image.Dispose()

End?Sub

Private?Function?MakeValidateCode()?As?String

'0?i?o

Dim?s()?As?Char?=?{?"0"c,?"1"c,?"2"c,?"3"c,?"4"c,?"5"c,?"6"c,?"7"c,?"8"c,?"9"c,?"A"c,?"B"c,?"C"c,?"D"c,?"E"c,?"F"c,?"G"c,?"J"c,?"K"c,?"L"c,?"M"c,?"N"c,?"P"c,?"Q"c,?"R"c,?"S"c,?"T"c,?"U"c,?"V"c,?"W"c,?"X"c,?"Y"c,?"Z"c?}

Dim?num?As?String?=?""

Dim?r?As?New?Random()

For?i?As?Integer?=?0?To?3

num?=?s(r.Next(0,?s.Length?-?1)).ToString()

Next?i

Return?num

End?Function

End?Class