VB.NET中文驗(yàn)證碼如何獲取

作者：佚名 2010-01-08 13:46:30

VB.NET中文驗(yàn)證碼的實(shí)現(xiàn)方式會(huì)在本文中為大家詳細(xì)介紹。希望初學(xué)者們可以通過本文介紹的相關(guān)內(nèi)容充分掌握其中知識(shí)。

我們?cè)谑褂?a >VB.NET這樣一款開發(fā)語言進(jìn)行編程的時(shí)候，需要認(rèn)清其中的特性，才能真正完善我們的程序開發(fā)。下面就先一起了解一下VB.NET中文驗(yàn)證碼的獲取首先要修改一下配置,C#中又checked和unchedked檢查整數(shù)溢出處理。#t#

但是VB.NET中沒辦法,溢出即報(bào)錯(cuò),***處理方法是

VB.net菜單：項(xiàng)目 --> XXX 屬性... --> 配置 --> 優(yōu)化 --> 選中“移除整數(shù)溢出檢查”復(fù)選框

下面來仔細(xì)研究一下VB.NET中文驗(yàn)證碼的相關(guān)代碼編寫：

Function RndStr()Function
RndStr() As String
Dim gb As SystemSystem.Text.
Encoding = System.Text.Encoding.
GetEncoding("gb2312")
Dim bytes As Object() =
CreateRegionCode(4)
Dim str1 As String = gb.GetString
(DirectCast(Convert.ChangeType
(bytes(0), GetType(Byte())), Byte()))
Dim str2 As String = gb.GetString
(DirectCast(Convert.ChangeType
(bytes(1), GetType(Byte())), Byte()))
Dim str3 As String = gb.GetString
(DirectCast(Convert.ChangeType
(bytes(2), GetType(Byte())), Byte()))
Dim str4 As String = gb.GetString
(DirectCast(Convert.ChangeType
(bytes(3), GetType(Byte())), Byte()))
Dim txt As String = (str1 &
str2 & str3 & str4)
End Function
Function CreateRegionCode()Function
CreateRegionCode(ByVal strlength
As Integer) As Object()
Dim rBase As String() = New String()
{"0", "1", "2", "3", "4", "5",
"6", "7", "8", "9", "a", "b",
"c", "d", "e", "f"}
Dim rnd As New Random
Dim bytes As Object() = New
Object(strlength - 1) {}
Dim i As Integer = 0
Do While (i < strlength)
Dim r2 As Integer
Dim r4 As Integer
Dim r1 As Integer = rnd.Next(11, 14)
Dim str_r1 As String = rBase(r1).Trim
rnd = New Random(r1 * DateTime.
Now.Ticks + i)
If (r1 = 13) Then
r2 = rnd.Next(0, 7)
Else
r2 = rnd.Next(0, &H10)
End If
Dim str_r2 As String = rBase(r2).Trim
Dim r3 As Integer = New Random(
(r2 * DateTime.Now.Ticks) + i).
Next(10, &H10)
Dim str_r3 As String = rBase(r3).Trim
rnd = New Random((r3 * DateTime.
Now.Ticks) + i)
Select Case r3
Case 10
r4 = rnd.Next(1, &H10)
Exit Select
Case 15
r4 = rnd.Next(0, 15)
Exit Select
Case Else
r4 = rnd.Next(0, &H10)
Exit Select
End Select
Dim str_r4 As String = rBase(r4).Trim
Dim byte1 As Byte = Convert.
ToByte((str_r1 & str_r2), &H10)
Dim byte2 As Byte = Convert.
ToByte((str_r3 & str_r4), &H10)
Dim str_r As Byte() = New Byte()
{byte1, byte2}
bytes.SetValue(str_r, i)
i += 1
Loop
Return bytes
End Function

VB.NET中文驗(yàn)證碼相關(guān)實(shí)現(xiàn)方法就為大家介紹到這里。

責(zé)任編輯：曹凱來源：博客園

VB.NET中文驗(yàn)證碼