DataUtils.cs

using System;
using System.Collections.Generic;
using System.Data;
using System.Reflection;
using System.Text;

namespace ChinhDo.Functions
{
    /// <summary>Utility functions for data</summary>
    public class DataUtils
    {
        /// <summary>
        /// Convert a List{T} to a DataTable.
        /// </summary>
        public static DataTable ToDataTable<T>(List<T> items)
        {
            var tb = new DataTable(typeof(T).Name);

            PropertyInfo[] props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);

            foreach (PropertyInfo prop in props)
            {
                Type t = GetCoreType(prop.PropertyType);
                tb.Columns.Add(prop.Name, t);
            }

            foreach (T item in items)
            {
                var values = new object[props.Length];

                for (int i = 0; i < props.Length; i++)
                {
                    values[i] = props[i].GetValue(item, null);
                }

                tb.Rows.Add(values);
            }

            return tb;
        }

        /// <summary>
        /// Break a <see cref="List{T}"/> into multiple chunks. The <paramref name="list="/> is cleared out and the items are moved
        /// into the returned chunks to minimize memory usage.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list">The list to be chunked.</param>
        /// <param name="chunkSize">The size of each chunk.</param>
        /// <returns>A list of chunks.</returns>
        public static List<List<T>> BreakIntoChunks<T>(List<T> list, int chunkSize)
        {
            if (chunkSize <= 0)
            {
                throw new ArgumentException("chunkSize must be greater than 0.");
            }

            List<List<T>> retVal = new List<List<T>>();

            while (list.Count > 0)
            {
                int count = list.Count > chunkSize ? chunkSize : list.Count;
                retVal.Add(list.GetRange(0, count));
                list.RemoveRange(0, count);
            }

            return retVal;
        }

        /// <summary>
        /// Determine of specified type is nullable
        /// </summary>
        public static bool IsNullable(Type t)
        {
            return !t.IsValueType || (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));
        }

        /// <summary>
        /// Return underlying type if type is Nullable otherwise return the type
        /// </summary>
        public static Type GetCoreType(Type t)
        {
            if (t != null && IsNullable(t))
            {
                if (!t.IsValueType)
                {
                    return t;
                }
                else
                {
                    return Nullable.GetUnderlyingType(t);
                }
            }
            else
            {
                return t;
            }
        }
    }
}