[RESOLVED] Error using xml deserialize, parsing xml into a struct with stringwriter()

Getting the following error from this code:

"System.InvalidOperationException: There was an error generating the XML document. ---> System.InvalidOperationException: The type xml_parser.Module1+Stats was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically."

Code:

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Imports System.IO
Imports System.Xml

Public Module Module1

    Sub Main()
        Dim host As New Stats

        host.Name = "test1"
        host.FQDN = "test1.lab.local"
        host.IP = "192.168.5.6"
        host.UserID = "user1"

        Console.WriteLine(ToXML(host))
        Console.ReadKey()
    End Sub

    'Convert Host data table to XML format for saving to file:
    Public Function ToXML(ByVal obj As Object) As String
        Try
            Dim x As Xml.Serialization.XmlSerializer = New Xml.Serialization.XmlSerializer(GetType(Object))
            Dim sw As New StringWriter()
            x.Serialize(sw, obj)
            Return sw.ToString
        Catch ex As Exception
            Console.WriteLine(ex.ToString)
            Console.ReadKey()
        End Try
    End Function

    Public Function ToStruct(ByVal xString As String, ByVal type As Type) As Object
        Dim x As New Xml.Serialization.XmlSerializer(type)
        Dim sw As New IO.StringReader(xString)
        Return x.Deserialize(sw)
    End Function

    ' Host data table details:
    <Serializable()> Public Structure Stats
        Dim Name As String
        Dim FQDN As String
        Dim IP As String
        Dim UserID As String
    End Structure

End Module

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By changing the ToXML method I got this to work.

Code:

---

    'Convert Host data table to XML format for saving to file:
    Public Function ToXML(ByVal obj As Stats) As String
        Try
            Dim x As Xml.Serialization.XmlSerializer = New Xml.Serialization.XmlSerializer(obj.GetType)
            Dim sw As New StringWriter()
            x.Serialize(sw, obj)
            Return sw.ToString
        Catch ex As Exception
            Console.WriteLine(ex.ToString)
            Console.ReadKey()
            Return Nothing
        End Try
    End Function

---

Fixed with a few minor structural changes, here is the new code:

Code:

---

Imports System.IO
Imports System.Xml.Serialization

Public Class xmlstuff
    Public Shared Function ToXML(ByVal host As Stats)
        Dim serializer As XmlSerializer = New XmlSerializer(GetType(Stats))

        Dim writer As New StringWriter()
        serializer.Serialize(writer, host)
        Return writer.ToString
    End Function

    Public Shared Function ToData(ByVal xString As String, ByVal type As Type) As Object
        Dim x As New Xml.Serialization.XmlSerializer(type)
        Dim sw As New IO.StringReader(xString)
        Return x.Deserialize(sw)
    End Function

End Class

Public Class Stats
    Public Property Name As String
    Public Property FQDN As String
    Public Property IP As String
    Public Property UserID As String
End Class

Public Module Module1

    Sub Main()
        Dim host As Stats = New Stats()

        host.Name = "test1"
        host.FQDN = "test1.lab.local"
        host.IP = "192.168.5.6"
        host.UserID = "user1"

        Console.WriteLine(xmlstuff.ToXML(host))
        Console.ReadKey()
    End Sub

End Module

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Thanks for this - yours is a simpler solution - I wasn't sure which one of my changes made it work.

Quote:

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Originally Posted by dbasnett

By changing the ToXML method I got this to work.

Code:

---

    'Convert Host data table to XML format for saving to file:
    Public Function ToXML(ByVal obj As Stats) As String
        Try
            Dim x As Xml.Serialization.XmlSerializer = New Xml.Serialization.XmlSerializer(obj.GetType)
            Dim sw As New StringWriter()
            x.Serialize(sw, obj)
            Return sw.ToString
        Catch ex As Exception
            Console.WriteLine(ex.ToString)
            Console.ReadKey()
            Return Nothing
        End Try
    End Function

---

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So - for my general education, can you explain why the change from:

Xml.Serialization.XmlSerializer(GetType(Object))

to:

Xml.Serialization.XmlSerializer(obj.GetType)

is what made the difference?

Thanks

Here is what I ended up with.

Code:

---

Imports System.IO
Imports System.Xml

Public Module Module1

    Sub Main()
        Dim host As New Stats

        host.Name = "test1"
        host.FQDN = "test1.lab.local"
        host.IP = "192.168.5.6"
        host.UserID = "user1"

        Dim path As String = "path to save / load here"

        Dim xe As XElement = XElement.Parse(ToXML(host))
        ' xe.Save(path) ' to save
        ' xe = XElement.Load(path) 'to load
        Console.WriteLine(xe.ToString)
        Dim rthost As Stats
        rthost = DirectCast(ToStruct(xe, rthost), Stats)
        Console.ReadKey()
    End Sub

    'Convert Host data table to XML format for saving to file:
    Public Function ToXML(ByVal obj As Stats) As String
        Try
            Dim x As Xml.Serialization.XmlSerializer = New Xml.Serialization.XmlSerializer(obj.GetType)
            Dim sw As New StringWriter()
            x.Serialize(sw, obj)
            Return sw.ToString
        Catch ex As Exception
            Console.WriteLine(ex.ToString)
            Console.ReadKey()
            Return Nothing
        End Try
    End Function

    Public Function ToStruct(ByVal el As XElement, ByVal type As Stats) As Object
        Dim x As New Xml.Serialization.XmlSerializer(type.GetType)
        Dim sw As XmlReader = el.CreateReader
        Return x.Deserialize(sw)
    End Function

    ' Host data table details:
    <Serializable()> Public Structure Stats
        Dim Name As String
        Dim FQDN As String
        Dim IP As String
        Dim UserID As String
    End Structure

End Module

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Nice. My next step is trying to use an array of Stats() to read/write a multi-host xml file.

Here is my simplistic approach using XElement, reading xml into the struct one field at a time. Is there a better way?

Code:

---

Module Module1

    Sub Main()
        Dim host As New List(Of Stats)

        Dim xelement As XElement = XElement.Load("xmldata.xml")
        Dim xmldata As IEnumerable(Of XElement) = xelement.Elements()
        ' Read the entire XML
        For Each stat In xmldata
            If (stat.Elements("Name").Any() And stat.Elements("FQDN").Any() And stat.Elements("IP").Any() And stat.Elements("UserID").Any()) Then
                Try
                    Dim hostentry As Stats = New Stats(stat.Element("Name").Value, stat.Element("FQDN").Value, stat.Element("IP").Value, stat.Element("UserID").Value)
                    host.Add(hostentry)
                Catch ex As Exception
                    Console.WriteLine(ex.ToString)
                    Console.ReadKey()
                End Try

            End If
        Next stat

        For Each stat In host
            Console.WriteLine("{0} has IP of {1} and UserID of {2}", stat.Name, stat.IP, stat.UserID)
        Next

        Console.ReadKey()
    End Sub

    <Serializable()> Public Structure Stats
        Dim Name As String
        Dim FQDN As String
        Dim IP As String
        Dim UserID As String
        Public Sub New(N As String, F As String, I As String, U As String)
            Name = N
            FQDN = F
            IP = I
            UserID = U
        End Sub
    End Structure
End Module

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