System.Xml.XmlBaseWriter.NamespaceManager.LookupNamespace C# (CSharp) Méthode

            public string LookupNamespace(string prefix)
            {
                int nsCount = _nsCount;
                if (prefix.Length == 0)
                {
                    for (int i = nsCount - 1; i >= _nsTop; i--)
                    {
                        Namespace nameSpace = _namespaces[i];
                        if (nameSpace.Prefix.Length == 0)
                            return nameSpace.Uri;
                    }
                    return string.Empty;
                }
                if (prefix.Length == 1)
                {
                    char prefixChar = prefix[0];
                    for (int i = nsCount - 1; i >= _nsTop; i--)
                    {
                        Namespace nameSpace = _namespaces[i];
                        if (nameSpace.PrefixChar == prefixChar)
                            return nameSpace.Uri;
                    }
                    return null;
                }
                for (int i = nsCount - 1; i >= _nsTop; i--)
                {
                    Namespace nameSpace = _namespaces[i];
                    if (nameSpace.Prefix == prefix)
                        return nameSpace.Uri;
                }
                if (prefix == "xmlns")
                    return xmlnsNamespace;
                if (prefix == "xml")
                    return xmlNamespace;
                return null;
            }