System.Xml.Xsl.Xslt.XsltInput.LookupXmlNamespace C# (CSharp) Method

        public string LookupXmlNamespace(string prefix) {
            Debug.Assert(prefix != null);
            string nsUri = reader.LookupNamespace(prefix);
            if (nsUri != null) {
                return nsUri;
            }
            if (prefix.Length == 0) {
                return string.Empty;
            }
            ReportError(/*[XT0280]*/Res.Xslt_InvalidPrefix, prefix);
            return null;
        }