Got error while reading XML file, XML Document (2,2) contains an error

Question

I created and CS file with XSD.exe with the help of volenteer @Petrus 【KIM】 but now i get the mentioned error at the beginning XML Document (2,2) contains an error. I don't know what this error is for.
The code:

 static XMLInvoice invoice(string file)  
        {  
            XMLInvoice i ;  
  
            string path = file;  
  
            XmlSerializer serializer = new XmlSerializer(typeof(XMLInvoice));  
  
            FileStream fs = new FileStream(file, FileMode.Open);  
            i = (XMLInvoice)serializer.Deserialize(fs);  
            fs.Close();  
            return i;  
}  

Hopefully somebody can help

Answer 1

For demonstration I shorten your XML sample to, (save it to a file on disc)

<?xml version="1.0" encoding="UTF-8"?>
<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2">
  <cbc:ID>03000</cbc:ID>
  <cbc:IssueDate>2021-11-18</cbc:IssueDate>
  <cbc:Note>Klant 6176 Factuur 03000</cbc:Note>
</Invoice>

Class file for XML above will be (Class with Nested Partial Class as you already have)

public class XMLInvoice
  {
    [System.SerializableAttribute()]
    [System.ComponentModel.DesignerCategoryAttribute("code")]
    [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true, Namespace = "urn:oasis:names:specification:ubl:schema:xsd:Invoice-2")]
    [System.Xml.Serialization.XmlRootAttribute(Namespace = "urn:oasis:names:specification:ubl:schema:xsd:Invoice-2", IsNullable = false)]
    public partial class Invoice
    {
      private ushort idField;
      private System.DateTime issueDateField;
      private string noteField;

      [System.Xml.Serialization.XmlElementAttribute(Namespace = "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2")]
      public ushort ID
      {
        get
        {
          return this.idField;
        }
        set
        {
          this.idField = value;
        }
      }

      [System.Xml.Serialization.XmlElementAttribute(Namespace = "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2", DataType = "date")]
      public System.DateTime IssueDate
      {
        get
        {
          return this.issueDateField;
        }
        set
        {
          this.issueDateField = value;
        }
      }

      [System.Xml.Serialization.XmlElementAttribute(Namespace = "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2")]
      public string Note
      {
        get
        {
          return this.noteField;
        }
        set
        {
          this.noteField = value;
        }
      }
    }
  }

To read XML file and get values, use this

private void GetXMLData()
  {
    XMLInvoice.Invoice MyData;
    string file = @"<place here full apth and name of XML sample file";
    System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(typeof(XMLInvoice.Invoice));
    using (System.IO.Stream reader = new System.IO.FileStream(file, System.IO.FileMode.Open))
    {
      MyData = (XMLInvoice.Invoice)serializer.Deserialize(reader);
    }
    ushort ID = MyData.ID;
    DateTime IssueDate = MyData.IssueDate;
    string Note = MyData.Note;
  }

Run in Debug.....

Answer 2

Don´t know why previous comment gets removed, anyway, try sample above