using System; using System.Collections.Generic; using System.Data; using System.Linq; using System.Reflection; using System.Collections; namespace XHSoft.LicenseManagerUI { /// <summary> /// 扩展属性 /// </summary> public static class Extensions { #region 数据集转换泛型集合扩展 /// <summary> /// DataSet转换为泛型集合 /// </summary> /// <typeparam name="T">泛型类型</typeparam> /// <param name="ds">DataSet数据集</param> /// <param name="tableIndex">待转换数据表索引,默认第0张表</param> /// <returns>返回泛型集合</returns> public static IList<T> ToList<T>(this DataSet ds, int tableIndex = 0) { if (ds == null || ds.Tables.Count < 0) return null; if (tableIndex > ds.Tables.Count - 1) return null; if (tableIndex < 0) tableIndex = 0; DataTable dt = ds.Tables[tableIndex]; // 返回值初始化 IList<T> result = new List<T>(); for (int j = 0; j < dt.Rows.Count; j++) { T _t = (T)Activator.CreateInstance(typeof(T)); PropertyInfo[] propertys = _t.GetType().GetProperties(); foreach (PropertyInfo pi in propertys) { for (int i = 0; i < dt.Columns.Count; i++) { // 属性与字段名称一致的进行赋值 if (pi.Name.Equals(dt.Columns[i].ColumnName)) { // 数据库NULL值单独处理 if (dt.Rows[j][i] != DBNull.Value) pi.SetValue(_t, dt.Rows[j][i], null); else pi.SetValue(_t, null, null); break; } } } result.Add(_t); } return result; } /// <summary> /// DataTable转换为泛型集合 /// </summary> /// <typeparam name="T">泛型类型</typeparam> /// <param name="dt">DataTable数据表</param> /// <returns>返回泛型集合</returns> public static IList<T> ToList<T>(this DataTable dt) where T:class,new() { if (dt == null || dt.Rows.Count <= 0) return null; List<T> list =new List<T>(); #region 方法一： //T model; //Type infos = typeof(T); ////object tempValue; //foreach (DataRow dr in dt.Rows) //{ // model = new T(); // 1. // infos.GetProperties().ToList().ForEach(p =>p.SetValue(model, dr[p.Name], null)); // 2. // //infos.GetProperties().ToList().ForEach(p => // //{ // // tempValue = dr[p.Name]; // // if (!string.IsNullOrEmpty(tempValue.ToString())) // // p.SetValue(model, tempValue, null); // //}); // list.Add(model); //} #endregion #region 方法二： 比方法一快 PropertyInfo[] propertys = typeof(T).GetProperties(); for (int j = 0; j < dt.Rows.Count; j++) { T _t = (T)Activator.CreateInstance(typeof(T)); foreach (PropertyInfo pi in propertys) { // 属性与字段名称一致的进行赋值 if (pi.Name.Equals(dt.Columns[pi.Name].ColumnName)) { if (dt.Rows[j][pi.Name] != DBNull.Value) pi.SetValue(_t, dt.Rows[j][pi.Name], null); else pi.SetValue(_t, null, null); } } list.Add(_t); } #endregion return list; } /// <summary> /// DataSet转换为泛型集合 /// </summary> /// <typeparam name="T">泛型类型</typeparam> /// <param name="ds">DataSet数据集</param> /// <param name="tableName">待转换数据表名称,名称为空时默认第0张表</param> /// <returns>返回泛型集合</returns> public static IList<T> ToList<T>(this DataSet ds, string tableName) { int _TableIndex = 0; if (ds == null || ds.Tables.Count < 0) return null; if (string.IsNullOrEmpty(tableName)) return ToList<T>(ds, 0); for (int i = 0; i < ds.Tables.Count; i++) { // 获取Table名称在Tables集合中的索引值 if (ds.Tables[i].TableName.Equals(tableName)) { _TableIndex = i; break; } } return ToList<T>(ds, _TableIndex); } #endregion #region 泛型集合转换为数据集扩展 /// <summary> /// 将泛型集合转换成DataSet数据集 /// </summary> /// <typeparam name="T">T类型</typeparam> /// <param name="list">泛型集合</param> /// <returns>DataSet数据集</returns> public static DataSet ToDataSet<T>(this IList<T> list) { Type elementType = typeof(T); var ds = new DataSet(); var t = new DataTable(); ds.Tables.Add(t); elementType.GetProperties().ToList().ForEach(propInfo => t.Columns.Add(propInfo.Name, Nullable.GetUnderlyingType(propInfo.PropertyType) ?? propInfo.PropertyType)); foreach (T item in list) { var row = t.NewRow(); elementType.GetProperties().ToList().ForEach(propInfo => row[propInfo.Name] = propInfo.GetValue(item, null) ?? DBNull.Value); t.Rows.Add(row); } return ds; } /// <summary> /// 泛型集合转换成DataTable表 /// </summary> /// <typeparam name="T">T类型</typeparam> /// <param name="list">泛型集合</param> /// <returns>DataTable表</returns> public static DataTable ToDataTable<T>(this IList<T> list) { return ToDataTable(list, null); } /// <summary> /// 泛型集合转换成DataTable表 /// </summary> /// <typeparam name="T">T类型</typeparam> /// <param name="list">泛型集合</param> /// <param name="_tableName">Table名称</param> /// <returns>DataTable表</returns> public static DataTable ToDataTable<T>(this IList<T> list, string _tableName) { Type elementType = typeof(T); var dt = new DataTable(); if (_tableName == "null") dt.TableName = _tableName; elementType.GetProperties().ToList().ForEach(propInfo => dt.Columns.Add(propInfo.Name, Nullable.GetUnderlyingType(propInfo.PropertyType) ?? propInfo.PropertyType)); foreach (T item in list) { var row = dt.NewRow(); elementType.GetProperties().ToList().ForEach(propInfo => row[propInfo.Name] = propInfo.GetValue(item, null) ?? DBNull.Value); dt.Rows.Add(row); } return dt; } #endregion #region 以下为IEnumerable扩展实现 /// <summary> /// 给非强类型的IEnumerable返回头一个元素。 /// </summary> public static object First(this IEnumerable col) { foreach (var item in col) return item; throw new IndexOutOfRangeException(); } /// <summary> /// 给非强类型的IEnumerable返回头一个强类型的元素 /// </summary> public static object First<T>(this IEnumerable col) { return (T)col.First(); } /// <summary> /// 基本上和List<T>的ForEach方法一致。 /// </summary> public static void Each<T>(this IEnumerable<T> col, Action<T> handler) { foreach (var item in col) handler(item); } /// <summary> /// 带索引的遍历方法。 /// </summary> public static void Each<T>(this IEnumerable<T> col, Action<T, int> handler) { int index = 0; foreach (var item in col) handler(item, index++); } /// <summary> /// 可以半途中断执行的遍历方法。 /// </summary> public static void Each<T>(this IEnumerable<T> col, Func<T, bool> handler) { foreach (var item in col) if (!handler(item)) break; } /// <summary> /// 可以半途中段的带索引的遍历方法。 /// </summary> public static void Each<T>(this IEnumerable<T> col, Func<T, int, bool> handler) { int index = 0; foreach (var item in col) if (!handler(item, index++)) break; } #endregion #region 以下为IEnumerable<T>的非泛型实现 public static void Each<T>(this IEnumerable col, Action<object> handler) { foreach (var item in col) handler(item); } public static void Each<T>(this IEnumerable col, Action<object, int> handler) { int index = 0; foreach (var item in col) handler(item, index++); } public static void Each<T>(this IEnumerable col, Func<object, bool> handler) { foreach (var item in col) if (!handler(item)) break; } public static void Each<T>(this IEnumerable col, Func<object, int, bool> handler) { int index = 0; foreach (var item in col) if (!handler(item, index++)) break; } #endregion } }