using System; using System.Collections.Generic; using System.Text; using System.Data; using System.ComponentModel; using System.Reflection; public class CollectionHelper { private CollectionHelper() { } public static List<T> Distinct<T>(IList<T> list) { List<T> list1 = new List<T>(); foreach (T obj in list) { if (!list1.Contains(obj)) list1.Add(obj); } return list1; } public static DataTable ConvertTo<T>(IList<T> list) { DataTable table = CreateTable<T>(); Type entityType = typeof(T); PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(entityType); foreach (T item in list) { DataRow row = table.NewRow(); foreach (PropertyDescriptor prop in properties) { object val = prop.GetValue(item); if (val != null) row[prop.Name] = val; } table.Rows.Add(row); } return table; } public static IList<T> ConvertTo<T>(IList<DataRow> rows) { IList<T> list = null; if (rows != null) { list = new List<T>(); foreach (DataRow row in rows) { T item = CreateItem<T>(row); list.Add(item); } } return list; } public static IList<T> ConvertTo<T>(DataTable table) { if (table == null) { return null; } List<DataRow> rows = new List<DataRow>(); foreach (DataRow row in table.Rows) { rows.Add(row); } return ConvertTo<T>(rows); } public static T CreateItem<T>(DataRow row) { T obj = default(T); if (row != null) { obj = Activator.CreateInstance<T>(); foreach (DataColumn column in row.Table.Columns) { PropertyInfo prop = obj.GetType().GetProperty(column.ColumnName); try { object value = row[column.ColumnName]; prop.SetValue(obj, value, null); } catch { // You can log something here throw; } } } return obj; } public static DataTable CreateTable<T>() { Type entityType = typeof(T); DataTable table = new DataTable(entityType.Name); PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(entityType); foreach (PropertyDescriptor prop in properties) { if (prop.PropertyType.IsGenericType && prop.PropertyType.GetGenericTypeDefinition() == typeof(Nullable<>)) { NullableConverter converter = new NullableConverter(prop.PropertyType); table.Columns.Add(prop.Name, converter.UnderlyingType); } else table.Columns.Add(prop.Name, prop.PropertyType); } return table; } }
时间: 2024-11-05 13:28:44