[转] VB下几个非常有用的函数

'————————（1）————————————
'获得指定ini文件中某个节下面的所有键值 TrueZq,,需要下面的API声明
'Private Declare Function GetPrivateProfileSection Lib "kernel32" Alias "GetPrivateProfileSectionA" (ByVal lpAppName As String, ByVal lpReturnedString As String, ByVal nSize As Long, ByVal lpFileName As String) As Long
'返回一个字符串数组
'调用举例：
'Dim arrClass() As String
'arrClass = GetInfoSection("class", "d:\type.ini")
 
Public Function GetInfoSection(strSection As String, strIniFile As String) As String()
    Dim strReturn As String * 32767
    Dim strTmp As String
    Dim nStart As Integer, nEnd As Integer, i As Integer
    Dim sArray() As String
   
    Call GetPrivateProfileSection(strSection, strReturn, Len(strReturn), strIniFile)
   
    strTmp = strReturn
    i = 1
    Do While strTmp <> ""
        nStart = nEnd + 1
        nEnd = InStr(nStart, strReturn, vbNullChar)
        strTmp = Mid$(strReturn, nStart, nEnd - nStart)
        If Len(strTmp) > 0 Then
            ReDim Preserve sArray(1 To i)
            sArray(i) = strTmp
            i = i + 1
        End If
       
    Loop
    GetInfoSection = sArray
End Function

'————————（2）————————————
'作用：去掉字符串中的首尾空格、所有无效字符
'测试用例
'Dim strRes As String
'Dim strSour As String
'
'strSour = " " & vbNullChar & vbNullChar & " ab cd" & vbNullChar
'strRes = zqTrim(strSour)
'MsgBox " 长度=" & Len(strSour) & "值=111" & strRes & "222"
Public Function zqTrim(ByVal strSour As String) As String
    Dim strTmp As String
    Dim nLen As Integer
    Dim i As Integer, j As Integer
    Dim strNow As String, strValid() As String, strNew As String
    'strNow 当前字符
    'strValid 有效字符
    'strNew 最后生成的新字符
   
    strTmp = Trim$(strSour)
    nLen = Len(strTmp)
    If nLen < 1 Then
        zqTrim = ""
        Exit Function
    End If
    j = 0
    For i = 1 To nLen
        strNow = Mid(strTmp, i, 1) '每次读取一个字符
        'MsgBox Asc(strNow)
        If strNow <> vbNullChar And Asc(strNow) <> 9 Then '如果有效，则存入有效数组
            ReDim Preserve strValid(j)
            strValid(j) = strNow
            j = j + 1
        End If
   
    Next i
   
    strNew = Join(strValid, "") '将所有有效字符连接起来
    zqTrim = Trim$(strNew) '去掉字符串中的首尾空格
End Function

'————————（3）————————————
'检查文件是否存在,存在返回 TRUE,否则返回FALSE
Public Function CheckFileExist(strFile As String) As Boolean   
    If Dir(strFile, vbDirectory) <> "" Then
        CheckFileExist = True
    Else
        CheckFileExist = False
    End If
End Function

'————————（4）————————————
'获得指定ini文件中某个节下面某个子键的键值,需要下面的API声明
'Public Declare Function GetPrivateProfileString Lib "kernel32" Alias _
'    "GetPrivateProfileStringA" (ByVal lpApplicationName As String, _
'    ByVal lpKeyName As Any, ByVal lpDefault As String, ByVal lpReturnedString _
'    As String, ByVal nSize As Long, ByVal lpFileName As String) As Long
'返回一个字符串
'调用举例：
'Dim strRun As String
'strRun = GetiniValue("Windows","Run", "C:\Windows\Win.ini")

Public Function GetiniValue(ByVal lpKeyName As String, ByVal strName As String, ByVal strIniFile As String) As String
    Dim strTmp As String * 255
   
    Call GetPrivateProfileString(lpKeyName, strName, "", _
            strTmp, Len(strTmp), strIniFile)
    GetiniValue = Left$(strTmp, InStr(strTmp, vbNullChar) - 1)
   
End Function

'————————（5）————————————
'获得Windows目录 ,需要下面的API声明
'Private Declare Function GetWindowsDirectory Lib "kernel32" Alias "GetWindowsDirectoryA" (ByVal lpBuffer As String, ByVal nSize As Long) As Long
'返回一个字符串，如“C:\Windows”、“C:\Winnt”
'调用举例：
'Dim strWindir As String
'strWindir = GetWinDir()
Private Function GetWinDir()
    Dim windir As String * 100
    Call GetWindowsDirectory(windir, 100)
    GetWinDir = Left$(windir, InStr(windir, vbNullChar) - 1)
   
End Function

'————————（6）————————————
'获得Windows系统目录,需要下面的API声明
'Private Declare Function GetSystemDirectory Lib "kernel32" Alias "GetSystemDirectoryA" (ByVal lpBuffer As String, ByVal nSize As Long) As Long
'返回一个字符串，如“C:\Windows\System”、“C:\Winnt\System32”
'调用举例：
'Dim strSysDir As String
'strSysDir = GetSystemDir()
Private Function GetSystemDir()
    Dim strSysDir As String * 100
    Call GetSystemDirectory(strSysDir, 100)
    GetSystemDir = Left$(strSysDir, InStr(strSysDir, vbNullChar) - 1)   
End Function