System.Xml.XmlBaseWriter.StartElement C# (CSharp) Méthode

        private void StartElement(ref string prefix, string localName, string ns, XmlDictionaryString xNs)
        {
            if (IsClosed)
                ThrowClosed();

            if (_documentState == DocumentState.Epilog)
                throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SR.Format(SR.XmlOnlyOneRoot)));
            if (localName == null)
                throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new ArgumentNullException(nameof(localName)));
            if (localName.Length == 0)
                throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new ArgumentException(SR.Format(SR.InvalidLocalNameEmpty), nameof(localName)));
            if (_writeState == WriteState.Attribute)
                throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SR.Format(SR.XmlInvalidWriteState, "WriteStartElement", WriteState.ToString())));

            FlushBase64();
            AutoComplete(WriteState.Element);
            Element element = EnterScope();
            if (ns == null)
            {
                if (prefix == null)
                    prefix = string.Empty;

                ns = _nsMgr.LookupNamespace(prefix);

                if (ns == null)
                    throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new ArgumentException(SR.Format(SR.XmlUndefinedPrefix, prefix), nameof(prefix)));
            }
            else if (prefix == null)
            {
                prefix = _nsMgr.LookupPrefix(ns);

                if (prefix == null)
                {
                    prefix = string.Empty;
                    _nsMgr.AddNamespace(string.Empty, ns, xNs);
                }
            }
            else
            {
                _nsMgr.AddNamespaceIfNotDeclared(prefix, ns, xNs);
            }
            element.Prefix = prefix;
            element.LocalName = localName;
        }