如何判断文本文件的编码格式

哈哈！一周前我刚刚遇到类似问题 慷慨把代码给你吧！！顺便贴上所有格式转UTF8的代码
（我本来是给XML读取用的 MSXML太挑剔了 只读UTF-8格式- - 不过转UTF-8的还是有点问题 记事本打开看上去读取没有问题 但是用MSXML读取依然有点问题。）
原理：根据文件前两个字符判断

注意 放在一个模块里面。
使用：GetEncoding(文件路径)，返回一个Encoding枚举体（仿.net）

例如：
Dim ReturnEncoding As Encoding
ReturnEncoding = GetEncoding("C:\1.txt")

If ReturnEncoding = UTF8 Then
'UTF处理
ElseIf ReturnEncoding = Unicode Then
'Unicode
Elseif ReturnEncoding = UnicodeBigEndian Then
'Unicode-BE处理
Else
'ANSI处理
End If

＝＝＝＝＝＝＝＝模块Encoding.bas＝＝＝＝＝＝＝＝＝＝
Option Explicit

Public Enum Encoding
ANSI
Unicode
UnicodeBigEndian
UTF8
End Enum

Public Function GetEncoding(FileName As String) As Encoding
On Error GoTo Err

Dim fBytes(1) As Byte, freeNum As Integer
freeNum = FreeFile

Open FileName For Binary Access Read As #freeNum
Get #freeNum, , fBytes(0)
Get #freeNum, , fBytes(1)
Close #freeNum

If fBytes(0) = &HFF And fBytes(1) = &HFE Then GetEncoding = Unicode
If fBytes(0) = &HFE And fBytes(1) = &HFF Then GetEncoding = UnicodeBigEndian
If fBytes(0) = &HEF And fBytes(1) = &HBB Then GetEncoding = UTF8
Err:
End Function

Public Sub FileToUTF8(FileName As String)
Dim fBytes() As Byte, uniString As String, freeNum As Integer
Dim ADO_Stream As Object

freeNum = FreeFile

ReDim fBytes(FileLen(FileName))
Open FileName For Binary Access Read As #freeNum
Get #freeNum, , fBytes
Close #freeNum

uniString = StrConv(fBytes, vbUnicode)

Set ADO_Stream = CreateObject("ADODB.Stream")
With ADO_Stream
.Type = 2
.Mode = 3
.Charset = "utf-8"
.open
.WriteText uniString
.SaveToFile FileName, 2
.Close
End With
Set ADO_Stream = Nothing
End Sub