vb.net 怎么将网页验证码显示在窗体上

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

VB怎么弄验证码100分

我会C#.net的，不过逻辑应该一样，给你看下吧第一步： 创建生成随机字符的方法private string CreateValidate(int count)

{

//定义验证码中所有的字符

string allchar = "1,2,3,4,5,6,7,8,9,0,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";

//将验证码中所有的字符保存在一个字符串数组中

string[] allchararray = allchar.Split(',');

//初始化一个随机数

string randomcode = "";

int temp = -1;

//生成一个随机对象

Random rand = new Random();

//根据验证码的位数循环

for (int i = 0; i count; i++)

{

//主要是防止生成相同的验证码

if (temp != -1)

{

//加入时间的刻度

rand = new Random(i * temp * ((int)DateTime.Now.Ticks));

}

int t = rand.Next(35);

if (temp == t)

{

//相等的话重新生成

return CreateValidate(count);

}

temp = t;

randomcode += allchararray[t];

}

//在Session中保存随机验证码

Session["Valid"] = randomcode;

//返回生成的随机字符

return randomcode;

}第二步：创建生成图片的方法：private void CreateImageM(string validateCode)

{

//图像的宽度-与验证码的长度成一定比例

int iwidth = (int)(validateCode.Length * 11.5);

//创建一个长20，宽iwidth的图像对象

System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 20);

//创建一个新绘图对象

Graphics g = Graphics.FromImage(image);

//绘图用的字体和字号

Font f = new System.Drawing.Font("Arial", 10, System.Drawing.FontStyle.Bold);

//绘图用的刷子大小

Brush b = new System.Drawing.SolidBrush(Color.White);

//清除背景色，并以深橄榄绿的颜色填充

g.Clear(Color.DarkOliveGreen);

//格式化刷子属性-用指定的刷子、颜色等在指定的范围内画图

g.DrawString(validateCode, f, b, 3, 3);

//创建铅笔对象

Pen blackPen = new Pen(Color.Black, 0);

//创建随机对象

Random rand = new Random();

//随机画线

for (int i = 0; i 5; i++)

{

int y = rand.Next(image.Height);

g.DrawLine(blackPen, 0, y, image.Width, y);

}

//输出绘图

System.IO.MemoryStream ms = new System.IO.MemoryStream();

//将图像保存到指定的流

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

Response.ClearContent();

//配置输出类型

Response.ContentType = "image/Jpeg";

//输出内容

Response.BinaryWrite(ms.ToArray());

//清空不需要的资源

g.Dispose();

image.Dispose();

}第三步：在page_Load事件中调用CreateImageM(CreateValidate(4));第四步：判断服务器端的验证码是否与用户输入的相同protected void Button1_Click(object sender, EventArgs e)

{

//判断服务器端的验证码是否与用户输入的相同

if (TextBox1.Text == Session["Valid"].ToString())

{

//相同则提示欢迎信息

Response.Write("script language='javascript'alert('欢迎光临')/script");

}

else

{

//不相同则提示错误信息

Response.Write("script language='javascript'alert('对不起，验证码错误')/script");

}

}

求一个vb.net写的验证码？

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" /

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