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

        internal DataRow FindMergeTarget(DataRow row, DataKey key, Index ndx)
        {
            DataRow targetRow = null;

            // Primary key match
            if (key.HasValue)
            {
                Debug.Assert(ndx != null);
                int findRecord = (row._oldRecord == -1) ? row._newRecord : row._oldRecord;
                object[] values = key.GetKeyValues(findRecord);
                targetRow = FindByIndex(ndx, values);
            }
            return targetRow;
        }

        private void MergeTable(DataTable src, DataTable dst)
        {
            int  rowsCount = src.Rows.Count;
            bool wasEmpty  = dst.Rows.Count == 0;

            if (0 < rowsCount)
            {
                Index     ndxSearch   = null;
                DataKey   key         = null;
                ArrayList saveIndexes = dst.LiveIndexes;
                dst.indexes = new ArrayList();
                if (!wasEmpty && dst.primaryKey != null)
                {
                    key = GetSrcKey(src, dst);
                    if (key != null)
                    {
                        ndxSearch = dst.primaryKey.Key.GetSortIndex(DataViewRowState.OriginalRows | DataViewRowState.Added);
                    }
                }
                for (int i = 0; i < rowsCount; i++)
                {
                    DataRow sourceRow = src.Rows[i];
                    DataRow targetRow = null;
                    if (ndxSearch != null)
                    {
                        targetRow = dst.FindMergeTarget(sourceRow, key, ndxSearch);
                    }
                    dst.MergeRow(sourceRow, targetRow, preserveChanges, ndxSearch);
                }
                dst.indexes = saveIndexes;
                dst.ResetIndexes();
            }
            MergeExtendedProperties(src.ExtendedProperties, dst.ExtendedProperties);
        }