System.Data.Merger.GetSrcKey C# (CSharp) Method

        private DataKey GetSrcKey(DataTable src, DataTable dst)
        {
            if (src._primaryKey != null)
            {
                return src._primaryKey.Key;
            }

            DataKey key = default(DataKey);
            if (dst._primaryKey != null)
            {
                DataColumn[] dstColumns = dst._primaryKey.Key.ColumnsReference;
                DataColumn[] srcColumns = new DataColumn[dstColumns.Length];
                for (int j = 0; j < dstColumns.Length; j++)
                {
                    srcColumns[j] = src.Columns[dstColumns[j].ColumnName];
                }

                key = new DataKey(srcColumns, false); // DataKey will take ownership of srcColumns
            }

            return key;
        }
    }