Cómo leer Archivo de LCO del SAT

    Function FileToString(ByVal filePath As String) As String
        Dim f As FileStream

        f = New FileStream(filePath, FileMode.Open, FileAccess.Read)

        Dim streamLength As Integer = Convert.ToInt32(f.Length)
        Dim fileData As Byte() = New Byte(streamLength) {}

        f.Read(fileData, 0, streamLength)
        f.Close()
        Return System.Text.Encoding.Default.GetString(fileData)
    End Function

    Private Function LimpiaLCO(ByVal sPath As String, ByVal sFile As String) As String
        Dim RutaLCO As [String] = sPath
        Dim xmlLCO As String = RutaLCO & sFile
        'Dim objReader As New StreamReader(xmlLCO)

        Dim sRes As String = FileToString(xmlLCO) 'objReader.ReadToEnd()
        Dim posIni As Integer = sRes.LastIndexOf("<?xml", System.StringComparison.Ordinal)
        Dim posFin As Integer = sRes.LastIndexOf("</lco:LCO>", System.StringComparison.Ordinal)

        sRes = sRes.Substring(posIni, posFin)
        posFin = sRes.LastIndexOf("</lco:LCO>", System.StringComparison.Ordinal)

        sRes = sRes.Substring(0, posFin)
        Dim SW As StreamWriter
        Dim origName = xmlLCO.Remove(xmlLCO.Length - 4)
        origName += "Clean.XML"
        SW = File.CreateText(sPath)
        SW.WriteLine(sRes)
        SW.WriteLine("</lco:LCO>")
        SW.Close()
        Return origName
    End Function

    Private Shared Sub LoadLco(ByVal sPathFileLCO_Clean As String)
        'Dim RutaLCO As [String] = sPath
        Dim xmlLCO As String = sPathFileLCO_Clean  ' RutaLCO & sfileClean


        'Cargamos XML 
        Dim xdoc As XDocument = XDocument.Load(xmlLCO)

        'Query 
        Dim LCO = From Contribuyente In xdoc.Descendants("Contribuyente") _
               Select New With {Key .RFC = Contribuyente.Attribute("RFC").Value, _
                                Key .Certificados = Contribuyente.Descendants("Certificado")}

        'Resultado 
        For Each Contribuyente As Object In LCO
            Console.WriteLine(Contribuyente.RFC)

            For Each Certificado As Object In Contribuyente.Certificados
                Dim Result = ""
                Dim xAttribute = Certificado.Attribute("noCertificado")
                If xAttribute IsNot Nothing Then
                    Result += " " & Convert.ToString(xAttribute.Value)
                End If
                Dim attribute = Certificado.Attribute("ValidezObligaciones")
                If attribute IsNot Nothing Then
                    Result += " " & Convert.ToString(attribute.Value)
                End If
                Dim xAttribute1 = Certificado.Attribute("EstatusCertificado")
                If xAttribute1 IsNot Nothing Then
                    Result += " " & Convert.ToString(xAttribute1.Value)
                End If
                Dim attribute1 = Certificado.Attribute("FechaInicio")
                If attribute1 IsNot Nothing Then
                    Result += " " & Convert.ToString(attribute1.Value)
                End If
                Dim xAttribute2 = Certificado.Attribute("FechaFinal")
                If xAttribute2 IsNot Nothing Then
                    Result += " " & Convert.ToString(xAttribute2.Value)
                End If
                MessageBox.Show(Result)
            Next
        Next


    End Sub