public override void WriteXmlnsAttribute(string prefix, string ns)
{
if (IsClosed)
ThrowClosed();
if (ns == null)
throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull(nameof(ns));
if (_writeState != WriteState.Element)
throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SR.Format(SR.XmlInvalidWriteState, "WriteXmlnsAttribute", WriteState.ToString())));
if (prefix == null)
{
prefix = _nsMgr.LookupPrefix(ns);
if (prefix == null)
{
GeneratePrefix(ns, null);
}
}
else
{
_nsMgr.AddNamespaceIfNotDeclared(prefix, ns, null);
}
}