System.Data.DataTable.ReadXmlDiffgram C# (CSharp) Method

        private void ReadXmlDiffgram(XmlReader reader)
        {
            // fill correctly
            int d = reader.Depth;
            bool fEnforce = EnforceConstraints;
            EnforceConstraints = false;
            DataTable newDt;
            bool isEmpty;

            if (Rows.Count == 0)
            {
                isEmpty = true;
                newDt = this;
            }
            else
            {
                isEmpty = false;
                newDt = Clone();
                newDt.EnforceConstraints = false;
            }

            newDt.Rows._nullInList = 0;

            reader.MoveToContent();

            if ((reader.LocalName != Keywords.DIFFGRAM) && (reader.NamespaceURI != Keywords.DFFNS))
            {
                return;
            }

            reader.Read();
            if (reader.NodeType == XmlNodeType.Whitespace)
            {
                MoveToElement(reader, reader.Depth - 1 /*iCurrentDepth*/); // skip over whitespaces.
            }

            newDt._fInLoadDiffgram = true;

            if (reader.Depth > d)
            {
                if ((reader.NamespaceURI != Keywords.DFFNS) && (reader.NamespaceURI != Keywords.MSDNS))
                {
                    //we should be inside the dataset part
                    XmlDocument xdoc = new XmlDocument();
                    XmlElement node = xdoc.CreateElement(reader.Prefix, reader.LocalName, reader.NamespaceURI);
                    reader.Read();
                    if (reader.Depth - 1 > d)
                    {
                        XmlDataLoader xmlload = new XmlDataLoader(newDt, false, node, false);
                        xmlload._isDiffgram = true; // turn on the special processing
                        xmlload.LoadData(reader);
                    }
                    ReadEndElement(reader);
                }

                if (((reader.LocalName == Keywords.SQL_BEFORE) && (reader.NamespaceURI == Keywords.DFFNS)) ||
                    ((reader.LocalName == Keywords.MSD_ERRORS) && (reader.NamespaceURI == Keywords.DFFNS)))
                {
                    //this will consume the changes and the errors part
                    XMLDiffLoader diffLoader = new XMLDiffLoader();
                    diffLoader.LoadDiffGram(newDt, reader);
                }

                // get to the closing diff tag
                while (reader.Depth > d)
                {
                    reader.Read();
                }

                // read the closing tag
                ReadEndElement(reader);
            }

            if (newDt.Rows._nullInList > 0)
            {
                throw ExceptionBuilder.RowInsertMissing(newDt.TableName);
            }

            newDt._fInLoadDiffgram = false;
            List<DataTable> tableList = new List<DataTable>();
            tableList.Add(this);
            CreateTableList(this, tableList);

            // this is terrible, optimize it
            for (int i = 0; i < tableList.Count; i++)
            {
                DataRelation[] relations = tableList[i].NestedParentRelations;
                foreach (DataRelation rel in relations)
                {
                    if (rel != null && rel.ParentTable == tableList[i])
                    {
                        foreach (DataRow r in tableList[i].Rows)
                        {
                            foreach (DataRelation rel2 in relations)
                            {
                                r.CheckForLoops(rel2);
                            }
                        }
                    }
                }
            }

            if (!isEmpty)
            {
                Merge(newDt);
            }
            EnforceConstraints = fEnforce;
        }