VB将汉字字符串转换成 UTF-8格式

VB将汉字字符串转换成 UTF-8格式后按照JSON格式提交给服务器，偶数个汉字没有问题，但奇数个汉字时，会有问题，请大师指导。

Private Declare Function MultiByteToWideChar Lib "kernel32 " (ByVal CodePage As Long, ByVal dwFlags As Long, ByVal lpMultiByteStr As Long, ByVal cchMultiByte As Long, ByVal lpWideCharStr As Long, ByVal cchWideChar As Long) As Long
Private Declare Function WideCharToMultiByte Lib "kernel32 " (ByVal CodePage As Long, ByVal dwFlags As Long, ByVal lpWideCharStr As Long, ByVal cchWideChar As Long, ByVal lpMultiByteStr As Long, ByVal cchMultiByte As Long, ByVal lpDefaultChar As Long, ByVal lpUsedDefaultChar As Long) As Long
Private Const CP_ACP = 0 ' default to ANSI code page
Private Const CP_UTF8 = 65001 ' default to UTF-8 code page
Dim su As String
'字符转 UTF8
Public Function EncodeToBytes(ByVal sData As String) As Byte() ' Note: Len(sData) > 0
Dim aRetn() As Byte
Dim nSize As Long
nSize = WideCharToMultiByte(CP_UTF8, 0, StrPtr(sData), -1, 0, 0, 0, 0) - 1
If nSize = 0 Then Exit Function
ReDim aRetn(0 To nSize - 1) As Byte
WideCharToMultiByte CP_UTF8, 0, StrPtr(sData), -1, VarPtr(aRetn(0)), nSize, 0, 0
EncodeToBytes = aRetn
Erase aRetn

End Function

' UTF8 转字符
Public Function DecodeToBytes(ByVal sData As String) As Byte() ' Note: Len(sData) > 0
Dim aRetn() As Byte
Dim nSize As Long
nSize = MultiByteToWideChar(CP_UTF8, 0, StrPtr(sData), -1, 0, 0) - 1
If nSize = 0 Then Exit Function
ReDim aRetn(0 To 2 * nSize - 1) As Byte
MultiByteToWideChar CP_UTF8, 0, StrPtr(sData), -1, VarPtr(aRetn(0)), nSize
DecodeToBytes = aRetn
Erase aRetn

End Function

Private Sub Command1_Click()

Dim i As Integer
Dim s As String
Dim mBuff()   As Byte

Text1 = StrConv(EncodeToBytes("中国人"), vbUnicode) '将utf编码的数组转VB可处理字符

End Sub

Private Sub Command2_Click()
Text1 = DecodeToBytes(StrConv(Text1, vbFromUnicode))
End Sub