How to read current worksheet in vb6

Private Function pvGetFileAsMultipart(filePath As String, sFileName As String, boundary As String) As Byte()
    Dim nFile As Integer
    Dim sPostData As String
     '--- read file
    nFile = FreeFile
     Open (filePath + "\" + sFileName) For Binary Access Read As nFile
    If LOF(nFile) > 0 Then
        ReDim baBuffer(0 To LOF(nFile) - 1) As Byte
        Get nFile, , baBuffer
        sPostData = StrConv(baBuffer, vbUnicode)
    End If
    Close nFile
    '--- prepare body
    sPostData = "--" & boundary & vbCrLf & _
        "Content-Disposition: form-data; name=""" + sFileName + """; filename=""" & sFileName & """" & vbCrLf & _
        "Content-Type: application/octet-stream" & vbCrLf & vbCrLf & _
        sPostData & vbCrLf & _
        "--" & boundary & "--"
    '--- post
    pvGetFileAsMultipart = StrConv(sPostData, vbFromUnicode)
End Function