Exemple #1
0
        /// <summary>
        /// Selects rows in which the value of the given column matches the given criteria.
        /// </summary>
        /// <typeparam name="T">The type of the row data.</typeparam>
        /// <param name="columnName">The name of the column.</param>
        /// <param name="selector">A function which accepts or rejects values.</param>
        /// <returns>A new view, containing only those rows in which the <paramref name="columnName"/> value was accepted by
        /// the <paramref name="selector"/>.</returns>
        public DataView Where <T> (string columnName, Func <T, bool> selector)
        {
            if (columnName == null)
            {
                throw new ArgumentNullException(nameof(columnName));
            }
            if (selector == null)
            {
                throw new ArgumentNullException(nameof(selector));
            }

            int columnIndex = GetColumnIndex(columnName);
            IReadOnlyDataList <T> column = (IReadOnlyDataList <T>)columns[columnIndex];

            List <int> newMap = new List <int>();

            for (int i = 0; i < map.Count; i++)
            {
                T    value   = column[map[i]];
                bool include = selector(value);
                if (include)
                {
                    newMap.Add(map[i]);
                }
            }

            return(new DataView(this.columns, newMap));
        }
Exemple #2
0
        /// <summary>
        /// Sorts all rows by the given function of the given column.
        /// </summary>
        /// <typeparam name="T">The type of values being compared.</typeparam>
        /// <param name="columnName">The column to sort on.</param>
        /// <param name="comparer">A comparison function of <paramref name="columnName"/> values.</param>
        /// <returns>A view of the data sorted by the function of the given column.</returns>
        public DataView OrderBy <T>(string columnName, Comparison <T> comparer)
        {
            if (columnName == null)
            {
                throw new ArgumentNullException(nameof(columnName));
            }
            if (comparer == null)
            {
                throw new ArgumentNullException(nameof(comparer));
            }

            int columnIndex = GetColumnIndex(columnName);
            IReadOnlyDataList <T> column = (IReadOnlyDataList <T>)columns[columnIndex];

            List <int> newMap = new List <int>(map);

            newMap.Sort((i, j) => comparer(column[i], column[j]));

            return(new DataView(this.columns, newMap));
        }