关于一个serializer 的问题

[Neusoft06]

方法1

    Public Shared Function DeserializingXml_1(Of T)(ByRef instance As T, ByVal path As String) As Boolean

        Try
            '生成DataContractSerializer
            Dim serializer As New DataContractSerializer(GetType(T))
            '读入文件
            Using fs As FileStream = New FileStream(path, FileMode.Open)
                '---这里报错
                instance = DirectCast(serializer.ReadObject(fs), T)
            End Using
            Return True

        Catch ex As Exception
            XmlSerialize.ErrorMessage = ex.Message
            Return False

        End Try

    End Function

方法2

  Private Sub deserializingXml(Of Type As Class)(ByRef refInstance As Type, ByVal path As String)
        refInstance = Nothing
        Dim fs As FileStream = Nothing
        Try
            Dim sr As New System.Xml.Serialization.XmlSerializer(GetType(Type))
            fs = New FileStream(path, FileMode.Open, FileAccess.Read)
            Try
                refInstance = DirectCast(sr.Deserialize(fs), Type)
            Finally
                fs.Close()
            End Try
        Catch
            Throw
        Finally
            If refInstance Is Nothing Then
                Console.WriteLine("Error--->Deserialize")

            End If
        End Try
    End Sub

调用

 Public Function Load(Of Type As Class)(ByRef instance As Type, ByVal path As String) As Boolean
        Try
            ' 这里调用方法
            DeserializingXml(instance, path)
        Catch
            Return False
        End Try
        Return True
    End Function

            If path Is Nothing Then
                filePath = "文件名.xml"
            Else
                filePath = path
            End If

            Dim loadData As TraceabilityConfig = Nothing
            If Not (New XmlSerialize()).Load(loadData, filePath) Then
                Return False
            End If

为什么使用方法1会报错--命名空间为空
方法2就没问题