How to delete first line of XML file using XMLDocument in C#?

Question

I don't see why you would want to remove that. But if it is required, you could try this:

XmlDocument doc = new XmlDocument();
doc.Load("something");

foreach (XmlNode node in doc)
{
    if (node.NodeType == XmlNodeType.XmlDeclaration)
    {
        doc.RemoveChild(node);
    }
}

or with LINQ:

var declarations = doc.ChildNodes.OfType<XmlNode>()
    .Where(x => x.NodeType == XmlNodeType.XmlDeclaration)
    .ToList();

declarations.ForEach(x => doc.RemoveChild(x));

I needed to have an XML serialized string without the declaration header so the following code worked for me.

StringBuilder sb = new StringBuilder();
XmlWriterSettings settings = new XmlWriterSettings {
    Indent = true,
    OmitXmlDeclaration = true, // this makes the trick :)
    IndentChars = "  ",
    NewLineChars = "\n",
    NewLineHandling = NewLineHandling.Replace
};
using (XmlWriter writer = XmlWriter.Create(sb, settings)) {
    doc.Save(writer);
}
return sb.ToString();

Alternatively you can use this;

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(xml);
if (xmlDoc.FirstChild.NodeType == XmlNodeType.XmlDeclaration)
    xmlDoc.RemoveChild(xmlDoc.FirstChild);

A very quick and easier solution is using the DocumentElement property of the XmlDocument class:

XmlDocument doc = new XmlDocument();
doc.Load(xmlSourceFile);
Console.Out.Write(doc.DocumentElement.OuterXml);