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There is an error in XML document (1, 1). When deserializing a simple xml string

I checked this post before but it didn't help me(it doesn't have an accepted answer either).
This test fails:
using System.IO;
using System.Xml.Serialization;
using Xunit;
namespace ATest
{
public class XmlSerializerTest
{
[Fact]
public void DeserializeTest()
{
string request = Serializer.ByteArrayToString(new RegisterRequest{ ... }
.ToXml());
RegisterRequest deserialized = request.DeserializeXmlString<RegisterRequest>();
Assert.NotNull(deserialized);
}
}
public static class Serializer
{
public static T DeserializeXmlString<T>(this string xmlObj)
{
T outputObject;
using (StringReader xmlReader = new StringReader(xmlObj))
{
var serializer = new XmlSerializer(typeof(T));
outputObject = (T)serializer.Deserialize(xmlReader); // throws here
}
return outputObject;
}
public static byte[] ToXml<T>(this T obj)
{
XmlWriterSettings settings = new XmlWriterSettings();
settings.Encoding = Encoding.UTF8;
settings.Indent = false;
using MemoryStream ms = new MemoryStream();
using XmlWriter xmlWriter = XmlWriter.Create(ms, settings);
XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
namespaces.Add(String.Empty, String.Empty);
XmlSerializer serializer = new XmlSerializer(typeof(T));
serializer.Serialize(xmlWriter, obj, namespaces);
return ms.ToArray();
}
// And convert that byte[] to string with this:
public static string ByteArrayToString(byte[] bytes) =>
Encoding.UTF8.GetString(bytes);
}
[XmlRoot(elementName: "RegisterRequest")]
public class RegisterRequest
{
[XmlElement]
public int WorkerId;
[XmlElement]
public string WorkerIP;
[XmlElement]
public int WorkerPort;
}
}
The error I get is:
System.InvalidOperationException: 'There is an error in XML document (1, 1).'
InnerException
XmlException: Data at the root level is invalid. Line 1, position 1.

Problem here is Encoding.UTF8 is UTF-8 encoding with BOM (byte order mark), which means XmlSerializer emits several bytes at the beginning to indicate said byte order mark. So result of your ToXml contains those non-character bytes at the beginning, and deserialization fails, because deserialization does not expect them. To fix, tell serializer to not emit BOM by doing this:
XmlWriterSettings settings = new XmlWriterSettings();
//settings.Encoding = Encoding.UTF8;
settings.Encoding = new UTF8Encoding(false); // false means no BOM here
By the way, text you pasted into the question does NOT contain said invisible characters, so with that specific hardcoded string you pasted the problem is not reproducable. However, since you included the code which produced problem string - one can reproduce it by manually calling ByteArrayToString(ToXml(..)).

XML Deserialization encoding issue

I already searched a lot and unable to find a solution and unable to determine the correct approach
I am serializing an object to xml string and deserializing it back to an object using c#. XML string after serialization adds a leading ?. When I dezerialize it back to the object I am getting an error There is an error in XML document (1, 1)
?<?xml version="1.0" encoding="utf-16"?>
Serialization code:
string xmlString = null;
MemoryStream memoryStream = new MemoryStream();
XmlSerializer xs = new XmlSerializer(typeof(T));
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add("abc", "http://example.com/abc/");
XmlTextWriter xmlTextWriter = new XmlTextWriter(memoryStream,Encoding.Unicode);
xs.Serialize(xmlTextWriter, obj, ns);
memoryStream = (MemoryStream)xmlTextWriter.BaseStream;
xmlString = ConvertByteArrayToString(memoryStream.ToArray());
ConvertByteArrayToString:
UnicodeEncoding encoding = new UnicodeEncoding();
string constructedString = encoding.GetString(characters);
Deserialization Code:
XmlSerializer ser = new XmlSerializer(typeof(T));
StringReader stringReader = new StringReader(xml);
XmlTextReader xmlReader = new XmlTextReader(stringReader);
object obj = ser.Deserialize(xmlReader);
xmlReader.Close();
stringReader.Close();
return (T)obj;
I would like to know what I am doing wrong with encoding and I need a solution that works for most cases. Thanks

Use following function for serialization and Deserialization
public static string Serialize<T>(T dataToSerialize)
{
try
{
var stringwriter = new System.IO.StringWriter();
var serializer = new XmlSerializer(typeof(T));
serializer.Serialize(stringwriter, dataToSerialize);
return stringwriter.ToString();
}
catch
{
throw;
}
}
public static T Deserialize<T>(string xmlText)
{
try
{
var stringReader = new System.IO.StringReader(xmlText);
var serializer = new XmlSerializer(typeof(T));
return (T)serializer.Deserialize(stringReader);
}
catch
{
throw;
}
}

Your serialized XML contains a Unicode byte-order mark in the beginning, and this is where the deserializer fails.
To remove the BOM you need to create a different version of encoding suppressing BOM instead of using default Encoding.Unicode:
new XmlTextWriter(memoryStream, new UnicodeEncoding(false, false))
Here the second false prevents BOM being prepended to the string.

format the xml output

I am using this method to transform an object to XML:
protected XmlDocument SerializeAnObject(object obj)
{
XmlDocument doc = new XmlDocument();
DataContractSerializer serializer = new DataContractSerializer(obj.GetType());
MemoryStream stream = new MemoryStream();
try
{
serializer.WriteObject(stream, obj);
stream.Position = 0;
doc.Load(stream);
return doc;
}
finally
{
stream.Close();
stream.Dispose();
}
}
Eventually I get something like:
<CaCT>
<CTC i:nil="true" xmlns="http://schemas.datacontract.org/2004/07/a.b.BusinessEntities.InnerEntities" />
<CTDescr xmlns="http://schemas.datacontract.org/2004/07/a.b.BusinessEntities.InnerEntities">blabla</CTDescr>
<CaId>464</CaId>
</CaCT>
How can I get rid of the i:nil="true" and the xmlns="http://schemas.datacontract.org/2004/07/a.b.BusinessEntities.InnerEntities"?

Personally I've always found that hand-written XML serialization with LINQ to XML works well. It's as flexible as you want, you can make it backward and forward compatible in whatever way you want, and obviously you don't end up with any extra namespaces or attributes that you don't want.
Obviously it becomes more complicated the more complicated your classes are, but I've found it works very well for simple classes. It's at least an alternative to consider.

protected string SerializeAnObject(object obj)
{
XmlSerializerNamespaces xmlNamespaces = new XmlSerializerNamespaces();
xmlNamespaces.Add("", "");
XmlWriterSettings writerSettings = new XmlWriterSettings();
writerSettings.OmitXmlDeclaration = true;
XmlSerializer serializer = new XmlSerializer(obj.GetType());
using (MemoryStream ms = new MemoryStream())
{
using (XmlWriter stream = XmlWriter.Create(ms, writerSettings))
{
serializer.Serialize(stream, obj, xmlNamespaces);
return Encoding.UTF8.GetString(ms.ToArray());
}
}
}

remove encoding from xmlserializer

I am using the following code to create an xml document -
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add("", "");
new XmlSerializer(typeof(docket)).Serialize(Console.Out, i, ns);
this works great in creating the xml file with no namespace attributes. i would like to also have no encoding attribute in the root element, but I cannot find a way to do it. Does anyone have any idea if this can be done?
Thanks

Old answer removed and update with new solution:
Assuming that it's ok to remove the xml declaration completly, because it makes not much sense without the encoding attribute:
XmlSerializerNamespaces ns = new XmlSerializerNamespaces(); ns.Add("", "");
using (XmlWriter writer = XmlWriter.Create(Console.Out, new XmlWriterSettings { OmitXmlDeclaration = true}))
{
new XmlSerializer(typeof (SomeType)).Serialize(writer, new SomeType(), ns);
}

To remove encoding from XML header pass TextWriter with null encoding to XmlSerializer:
MemoryStream ms = new MemoryStream();
XmlTextWriter w = new XmlTextWriter(ms, null);
s.Serialize(w, vs);
Explanation
XmlTextWriter uses encoding from TextWriter passed in constructor:
// XmlTextWriter constructor
public XmlTextWriter(TextWriter w) : this()
{
this.textWriter = w;
this.encoding = w.Encoding;
..
It uses this encoding when generating XML:
// Snippet from XmlTextWriter.StartDocument
if (this.encoding != null)
{
builder.Append(" encoding=");
...

string withEncoding;
using (System.IO.MemoryStream memory = new System.IO.MemoryStream()) {
using (System.IO.StreamWriter writer = new System.IO.StreamWriter(memory)) {
serializer.Serialize(writer, obj, null);
using (System.IO.StreamReader reader = new System.IO.StreamReader(memory)) {
memory.Position = 0;
withEncoding= reader.ReadToEnd();
}
}
}
string withOutEncoding= withEncoding.Replace("<?xml version=\"1.0\" encoding=\"utf-8\"?>", "");

Credit to this blog for helping me with my code
http://blog.dotnetclr.com/archive/2008/01/29/removing-declaration-and-namespaces-from-xml-serialization.aspx
here's my solution, same idea, but in VB.NET and a little clearer in my opinion.
Dim sw As StreamWriter = New, StreamWriter(req.GetRequestStream,System.Text.Encoding.ASCII)
Dim xSerializer As XmlSerializer = New XmlSerializer(GetType(T))
Dim nmsp As XmlSerializerNamespaces = New XmlSerializerNamespaces()
nmsp.Add("", "")
Dim xWriterSettings As XmlWriterSettings = New XmlWriterSettings()
xWriterSettings.OmitXmlDeclaration = True
Dim xmlWriter As XmlWriter = xmlWriter.Create(sw, xWriterSettings)
xSerializer.Serialize(xmlWriter, someObjectT, nmsp)

How do I add a default namespace with no prefix using XMLSerializer

I am trying to generate an XML document that contains the default namespace without a prefix using XmlSerializer, e.g.
<?xml version="1.0" encoding="utf-8" ?>
<MyRecord ID="9266" xmlns="http://www.website.com/MyRecord">
<List>
<SpecificItem>
Using the following code ...
string xmlizedString = null;
MemoryStream memoryStream = new MemoryStream();
XmlSerializer xs = new XmlSerializer(typeof(ExportMyRecord));
XmlSerializerNamespaces xmlnsEmpty = new XmlSerializerNamespaces();
xmlnsEmpty.Add(string.Empty, string.Empty);
XmlTextWriter xmlTextWriter = new XmlTextWriter(memoryStream, Encoding.UTF8);
xs.Serialize(xmlTextWriter, myRecord, xmlnsEmpty);
memoryStream = (MemoryStream)xmlTextWriter.BaseStream;
xmlizedString = this.UTF8ByteArrayToString(memoryStream.ToArray());
and class structure ...
[Serializable]
[XmlRoot("MyRecord")]
public class ExportMyRecord
{
[XmlAttribute("ID")]
public int ID { get; set; }
Now, I've tried various options ...
XmlSerializer xs = new XmlSerializer
(typeof(ExportMyRecord),"http://www.website.com/MyRecord");
or ...
[XmlRoot(Namespace = "http://www.website.com/MyRecord", ElementName="MyRecord")]
gives me ...
<?xml version="1.0" encoding="utf-8"?>
<q1:MylRecord ID="9266" xmlns:q1="http://www.website.com/MyRecord">
<q1:List>
<q1:SpecificItem>
I need the XML to have the namespace without the prefix as it's going to a third party provider and they reject all other alternatives.

There you go:
ExportMyRecord instance = GetInstanceToSerializeFromSomewhere();
XmlSerializerNamespaces xmlnsEmpty = new XmlSerializerNamespaces();
xmlnsEmpty.Add(string.Empty, "http://www.website.com/MyRecord");
var serializer = new XmlSerializer(
instance.GetType(),
"http://www.website.com/MyRecord"
);

Here's a generic implementation that can be used for any type:
public static void Serialize<T>(T instance, string defaultNamespace, Stream stream)
{
var namespaces = new XmlSerializerNamespaces();
namespaces.Add(string.Empty, defaultNamespace);
var serializer = new XmlSerializer(typeof(T), defaultNamespace);
serializer.Serialize(stream, instance, namespaces);
}