Question

I’m new to the XmlSerializer. I’ve written a small class to hold entries from a database:

[Serializable]
public struct Entry
{
    public string artkey, lid, request, status, requestdate;
}

Simple enough, right? It should be a piece of cake to serialize a list of these.

I have a function that compiles a list of these. To serialize my list, I try the following code:

XmlSerializer serializer = new XmlSerializer(typeof(Entry));
System.IO.MemoryStream ms = new System.IO.MemoryStream();
serializer.Serialize(ms, entries.ToArray());
ms.WriteTo(Response.OutputStream);

This code prints the following exception:

<error>System.InvalidOperationException: There was an error generating the XML document. ---> System.InvalidCastException: Specified cast is not valid.
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterEntry.Write3_Entry(Object o)
   --- End of inner exception stack trace ---
   at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id)
   at System.Xml.Serialization.XmlSerializer.Serialize(Stream stream, Object o, XmlSerializerNamespaces namespaces)
   at System.Xml.Serialization.XmlSerializer.Serialize(Stream stream, Object o)
   at CCB_Requests.xmlResponse_selectFromCcb_Requests(HttpResponse response)
   at CCB_Requests.ProcessRequest(HttpContext context)</error>

It seems that I must be making a simple mistake. How can I fix this?

Answer 1

you are serializing an array of Entry, change the initialization of the XmlSerializer to:

// typeof(Entry) ==> typeof(Entry[])
XmlSerializer serializer = new XmlSerializer(typeof(Entry[]));