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vb.netlrc校验 crc校验vb源代码

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如何利用VB对一串数据进行LRC校验希望给出代码和例子分二步：
一、建立一个模块，复制下面代码
Option Explicit
Private Declare Function CryptAcquireContext Lib "advapi32.dll" _
Alias "CryptAcquireContextA" ( _
ByRef phProv As Long, _
ByVal pszContainer As String, _
ByVal pszProvider As String, _
ByVal dwProvType As Long, _
ByVal dwFlags As Long) As Long
Private Declare Function CryptReleaseContext Lib "advapi32.dll" ( _
ByVal hProv As Long, _
ByVal dwFlags As Long) As Long
Private Declare Function CryptCreateHash Lib "advapi32.dll" ( _
ByVal hProv As Long, _
ByVal Algid As Long, _
ByVal hKey As Long, _
ByVal dwFlags As Long, _
ByRef phHash As Long) As Long
Private Declare Function CryptDestroyHash Lib "advapi32.dll" ( _
ByVal hHash As Long) As Long
Private Declare Function CryptHashData Lib "advapi32.dll" ( _
ByVal hHash As Long, _
pbData As Any, _
ByVal dwDataLen As Long, _
ByVal dwFlags As Long) As Long
Private Declare Function CryptGetHashParam Lib "advapi32.dll" ( _
ByVal hHash As Long, _
ByVal dwParam As Long, _
pbData As Any, _
pdwDataLen As Long, _
ByVal dwFlags As Long) As Long
Private Const PROV_RSA_FULL = 1
Private Const CRYPT_NEWKEYSET = H8
Private Const ALG_CLASS_HASH = 32768
Private Const ALG_TYPE_ANY = 0
Private Const ALG_SID_MD2 = 1
Private Const ALG_SID_MD4 = 2
Private Const ALG_SID_MD5 = 3
Private Const ALG_SID_SHA1 = 4
Enum HashAlgorithm
MD2 = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_MD2
MD4 = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_MD4
MD5 = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_MD5
SHA1 = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_SHA1
End Enum
Private Const HP_HASHVAL = 2
Private Const HP_HASHSIZE = 4
Function HashString( _
ByVal Str As String, _
Optional ByVal Algorithm As HashAlgorithm = MD5) As String
Dim hCtx As Long
Dim hHash As Long
Dim lRes As Long
Dim lLen As Long
Dim lIdx As Long
Dim abData() As Byte
' Get default provider context handle
lRes = CryptAcquireContext(hCtx, vbNullString, _
vbNullString, PROV_RSA_FULL, 0)
If lRes0 Then
' Create the hash
lRes = CryptCreateHash(hCtx, Algorithm, 0, 0, hHash)
If lRes0 Then
' Hash the string
lRes = CryptHashData(hHash, ByVal Str, Len(Str), 0)
If lRes0 Then
' Get the hash lenght
lRes = CryptGetHashParam(hHash, HP_HASHSIZE, lLen, 4, 0)
If lRes0 Then
' Initialize the buffer
ReDim abData(0 To lLen - 1)
' Get the hash value
lRes = CryptGetHashParam(hHash, HP_HASHVAL, abData(0), lLen, 0)
If lRes0 Then
' Convert value to hex string
For lIdx = 0 To UBound(abData)
HashString = HashString_
Right$("0"Hex$(abData(lIdx)), 2)
Next
End If
End If
End If
' Release the hash handle
CryptDestroyHash hHash
End If
End If
' Release the provider context
CryptReleaseContext hCtx, 0
' Raise an error if lRes = 0
If lRes = 0 Then Err.Raise Err.LastDllError
End Function
二、函数调用
msgbox HashString(Text1.Text)
VB.NET如何对输入的数据进行合法性检验,过滤不合法的数据代码合法性校验有很多方法，要视情况而定，比如说可以用正则表达式，如果是数字，除了正则表达式，也可以用诸如TryParse这种方法 。
用VB6.0 写数据到PLC中过程中，调试提示 LRC = LRC(aa)中的“aa”数据类型不正确，请教大咖，我错在哪里你好歹应该加入LRC函数吧 。
Function LRC(ByVal s As String) As String
Dim sa, i As Integer, sum As Long
sa = Split(s)
For i = 0 To UBound(sa)
sum = sum + ("H"sa(i))

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