Too many

Question

I was finally able to create a Xml file with some coding (with lots of help here from some people). I can store the file but the next process is reading it back. This gave me an error: "Unexpected Xml declaration". After searching a bit I understand that a Xml file can have only one time <?xml version=1.0 etc>. But my document has several of these statements in the document. And therefore the code

xmlDocument doc = new XmlDocument

Throws me this error. The question is how do I get rid of all these comments in the xml document.

The document is create with 2 functions:

    private void btnSave_Click(object sender, EventArgs e)
    {

        //Check if all fields are filled in 
        if (txbCompany.Text == "" || txbSiteName.Text == "" || txbIMO.Text == "")
        {
            MessageBox.Show("Please fill in all empty fields");
            
        }
        else if (NumMachTot.Value == 0)
        {
            MessageBox.Show("A Client profile needs at least one assigned machine!");
        }
        else
        {
            var appData = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "VibroManager");
            Directory.CreateDirectory(appData);

            //Create the Company Profile Class
            CompanyProfile companyProfile = new CompanyProfile();
            companyProfile.CompanyName = txbCompany.Text;
            companyProfile.SiteName = txbSiteName.Text;
            companyProfile.Imo = txbIMO.Text;
            companyProfile.MachineTotal = (int)NumMachTot.Value;

            //Serialization of the companyProfile and append to the document
            System.Xml.Serialization.XmlSerializer x = new System.Xml.Serialization.XmlSerializer(typeof(CompanyProfile));
            using (var writer = new StreamWriter(Path.Combine(appData, $"{txbCompany.Text}_{txbSiteName.Text}.xml"), true))
            {
                x.Serialize(writer, companyProfile);
            }

            //Iterate the datasource list, NOT the DataGridView.
            foreach (MachineProfile machineProfile in dsMachineProfile)
           {
                AppendMachineData(machineProfile, fileName: Path.Combine(appData, $"{txbCompany.Text}_{txbSiteName.Text}.xml"));
           }

            //Close form and open Main form
            this.Hide();
            frmMain fMain = new frmMain();
            fMain.ShowDialog();
        }
    }

changed Code:

        private void AppendMachineData(MachineProfile machineProfile, string fileName)
    {
        //Serialization of the MachineProle and append to the document
        System.Xml.Serialization.XmlSerializer x = new System.Xml.Serialization.XmlSerializer(typeof(MachineProfile));
        var settings = new XmlWriterSettings();

        using (var writer = new StreamWriter(fileName, true))
        {
           
            settings.Indent = true;
            settings.OmitXmlDeclaration = true;
            x.Serialize(writer, machineProfile);
        }          
    }   

I think in these two functions the problem is created but in fact I do not know why and how. Or maybe there is another way to solve this.

This is the code that I use to read the xml file

    private void openToolStripMenuItem_Click(object sender, EventArgs e)
    {
        var filePath = string.Empty;

        using (OpenFileDialog openFileDialog = new OpenFileDialog())
        {
            openFileDialog.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData );
            openFileDialog.Filter = "All files (*.*)|*.*";
            openFileDialog.FilterIndex = 2;
            openFileDialog.RestoreDirectory = true;

            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                //Get the path of specified file
                filePath = openFileDialog.FileName;

                XmlDocument doc = new XmlDocument();
                doc.Load(filePath);

                XmlNode node = doc.DocumentElement.SelectSingleNode("/CompanyName");
                lblCompanyName.Text = node.InnerText;


            }
        }

    }

Here is a screenshot of the Xml file

Answer 1

Below shows how to use XML serialization which allows one to use classes to store one's data and then serialize these classes to save the data to an XML file. Deserialization reads the data from the XML file and populates the classes.

Try the following:

To each of the classes below, add the following using statements

• using System.Collections.Generic;
• using System.Xml;
• using System.Xml.Serialization;

Create a class (name: XmlCompanyProfile.cs)

public class XmlCompanyProfile
{
    public string CompanyName { get; set; }
    public string SiteName { get; set; }
    public int Imo { get; set; }
    public int MachineTotal { get; set; }
}

If an element name isn't specified, the name of the property is used in the XML file.

Example 1:

public string CompanyName { get; set; }

By specifying an ElementName, one can make the property name different than the name used in the XML file.

Example 2:

[XmlElement(ElementName = "Name")]
public string CompanyName { get; set; }

Of course, one can also set the value of ElementName to the property name.

Example 3:

[XmlElement(ElementName = "CompanyName")]
public string CompanyName { get; set; }

Note: In Example 3, since the element name is set to the same value as the property name, it will have the same result as Example 1.

If one wishes to specify the element names, the XmlCompanyProfile class will look like the following instead:

public class XmlCompanyProfile
{
    [XmlElement(ElementName = "CompanyName")]
    public string CompanyName { get; set; }

    [XmlElement(ElementName = "SiteName")]
    public string SiteName { get; set; }

    [XmlElement(ElementName = "Imo")]
    public int Imo { get; set; }

    [XmlElement(ElementName = "MachineTotal")]
    public int MachineTotal { get; set; }

}

Create a class (name: XmlMachineProfile.cs)

public class XmlMachineProfile
{
    [XmlElement(ElementName = "MachineName")]
    public string MachineName { get; set; }

    [XmlElement(ElementName = "NominalSpeed")]
    public int NominalSpeed { get; set; }
}

Create a class (name: XmlRoot.cs)

[XmlRoot(ElementName = "Root")]
public class XmlRoot
{
    [XmlElement(ElementName = "CompanyProfile")]
    public XmlCompanyProfile CompanyProfile { get; set; } = new XmlCompanyProfile();

    [XmlElement(ElementName = "MachineProfile")]
    public List<XmlMachineProfile> MachineProfiles { get; set; } = new List<XmlMachineProfile>();
}

---

To serialize and deserialize the data:

Create a class (name: HelperXml.cs)

public static class HelperXml
{
    public static T DeserializeXMLFileToObject<T>(string xmlFilename)
    {
        //Usage: Class1 myClass1 = DeserializeXMLFileToObject<Class1>(xmlFilename);

        T rObject = default(T);

        if (string.IsNullOrEmpty(xmlFilename))
        {
            throw new Exception($"Error: XML filename not specified (xmlFilename: '{xmlFilename}'");
        }

        using (System.IO.StreamReader xmlStream = new System.IO.StreamReader(xmlFilename))
        {
            System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(typeof(T));
            rObject = (T)serializer.Deserialize(xmlStream);
        }

        return rObject;
    }


    public static void SerializeObjectToXMLFile(object obj, string xmlFilename)
    {
        //Usage: Class1 myClass1 = new Class1();
        //SerializeObjectToXMLFile(myClass1, xmlFilename);

        if (string.IsNullOrEmpty(xmlFilename))
        {
            throw new Exception($"Error: XML filename not specified (xmlFilename: '{xmlFilename}'");
        }

        System.Xml.XmlWriterSettings settings = new System.Xml.XmlWriterSettings() { Indent = true, OmitXmlDeclaration = true};

        using (System.Xml.XmlWriter xmlWriter = System.Xml.XmlWriter.Create(xmlFilename, settings))
        {
            //specify namespaces
            System.Xml.Serialization.XmlSerializerNamespaces ns = new System.Xml.Serialization.XmlSerializerNamespaces();
            ns.Add(string.Empty, "urn:none"); //eliminates "xsd" and "xsi" namespaces

            //create new instance
            System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(obj.GetType());

            //serialize (write to XML file)
            serializer.Serialize(xmlWriter, obj, ns);
        }
    }
}

---

Usage (serialization):

Note: In the code below, the name of the button is btnSerialize.

private XmlRoot _root = null;

           ...

private void btnSerialize_Click(object sender, EventArgs e)
{
    //create new instance
    _root = new XmlRoot();

    //set CompanyProfile info
    _root.CompanyProfile.CompanyName = "ABB";
    _root.CompanyProfile.SiteName = "Rotterdam";
    _root.CompanyProfile.Imo = 123456;
    _root.CompanyProfile.MachineTotal = 3;

    //add machine profile
    _root.MachineProfiles.Add(new XmlMachineProfile() { MachineName = "Machine 1", NominalSpeed = 50 });
    _root.MachineProfiles.Add(new XmlMachineProfile() { MachineName = "Machine 2", NominalSpeed = 60 });
    _root.MachineProfiles.Add(new XmlMachineProfile() { MachineName = "Machine 3", NominalSpeed = 50 });

    //prompt user for XML filename
    using (SaveFileDialog sfd = new SaveFileDialog())
    {
        sfd.FileName = "Test.xml"; //default filename
        sfd.Filter = "XML File (*.xml)|*.xml";
        sfd.Title = "Save XML file";

        if (sfd.ShowDialog() == DialogResult.OK)
        {
            //serialize
            HelperXml.SerializeObjectToXMLFile(_root, sfd.FileName);
        }
    }
}

Usage (deserialization):

Note: In the code below, the name of the button is btnDeserialize.

private XmlRoot _root = null;

           ...

private void btnDeserialize_Click(object sender, EventArgs e)
{
    //prompt user for XML filename
    using (OpenFileDialog ofd = new OpenFileDialog())
    {
        ofd.Filter = "XML File (*.xml)|*.xml";
        ofd.Title = "Open XML file";

        if (ofd.ShowDialog() == DialogResult.OK)
        {
            //deserialize
            _root = HelperXml.DeserializeXMLFileToObject<XmlRoot>(ofd.FileName);

            System.Diagnostics.Debug.WriteLine($"CompanyName: '{_root.CompanyProfile.CompanyName}'");
        }
    }
}

---

Here's what the XML file looks like:

<Root>
  <CompanyProfile>
    <CompanyName>ABB</CompanyName>
    <SiteName>Rotterdam</SiteName>
    <Imo>123456</Imo>
    <MachineTotal>3</MachineTotal>
  </CompanyProfile>
  <MachineProfile>
    <MachineName>Machine 1</MachineName>
    <NominalSpeed>50</NominalSpeed>
  </MachineProfile>
  <MachineProfile>
    <MachineName>Machine 2</MachineName>
    <NominalSpeed>60</NominalSpeed>
  </MachineProfile>
  <MachineProfile>
    <MachineName>Machine 3</MachineName>
    <NominalSpeed>50</NominalSpeed>
  </MachineProfile>
</Root>

---

Resources:

• XML serialization
• Examples of XML Serialization
• XDocument Class
• JSON Utils