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由于太懒了,很久没更新了。毕业了,得好好装逼学习了,不能一心想着完了。
由于公司中的项目大量的使用DataTable,而每次对datatable进行操作的时候需要写很多相同的代码,所以秉着 装逼而学习 的态度,于是撸了几个扩展方法,记录下来,学习下。
class Program { public DataTable LinqTable = new DataTable(); void AddNewRow(int id, string name) { Random random = new Random(); DataRow newRow = LinqTable.NewRow(); Thread.Sleep(20); newRow["id"] = id; newRow["name"] = id + name; newRow["salary"] = (float)random.Next(10000) / 100; LinqTable.Rows.Add(newRow); } void MyTable() { LinqTable.Columns.Add(new DataColumn("id", typeof(int))); LinqTable.Columns.Add(new DataColumn("name", typeof(string))); LinqTable.Columns.Add(new DataColumn("salary", typeof(float))); } static void Main(string[] args) { Program program = new Program(); program.MyTable(); AddData(program); ForEach(program); Select(program); SelectOne(program); Contains(program); SingleOrDefault(program); AddColumnFiled(program); AddColumnFiledTwo(program); Max(program); Console.ReadKey(); } /// <summary> /// 给DataTable中的每条记录执行某个操作 /// </summary> /// <param name="table">DataTable</param> /// <param name="func">Func委托</param> static void ForEach(Program program) { Console.WriteLine("给DataTable中的每条记录执行某个操作"); ExMethod.ForEach(program.LinqTable, (DataRow row) => { row["id"] = int.Parse(row["id"].ToString()) * 10; }); for (var i = 0; i < program.LinqTable.Rows.Count; i++) { DataRow row = program.LinqTable.Rows[i]; foreach (var it in row.ItemArray) { Console.Write(it + " "); } Console.WriteLine(); } Console.WriteLine(); } /// <summary> /// 从DataTable中获取某个字段组成的集合 /// </summary> /// <typeparam name="T">字段的数据类型</typeparam> /// <param name="table">DataTable</param> /// <param name="selector">Func委托</param> /// <returns>IEnumerable</returns> static void Select(Program program) { Console.WriteLine("从DataTable中获取某个字段组成的集合"); List<int> list = (List<int>)ExMethod.Select<int>(program.LinqTable, "id"); foreach (var it in list) { Console.WriteLine(it); } Console.WriteLine(); } /// <summary> /// 获取DataTable中某个字段符合给定条件的处理过的集合 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="name"></param> /// <param name="func"></param> /// <returns></returns> static void SelectOne(Program program) { Console.WriteLine("获取DataTable中某个字段符合给定条件的处理过的集合"); List<int> list = (List<int>)ExMethod.Select<int>(program.LinqTable, "id", (int x) => { return x + 10; }); foreach (var it in list) { Console.WriteLine(it); } Console.WriteLine(); } /// <summary> /// 判断给定DataTable中是否存在某个字段值符合给定条件的记录 /// </summary> /// <typeparam name="T">给定字段的数据类型</typeparam> /// <param name="table">DataTable</param> /// <param name="name">字段名称</param> /// <param name="predicate">Func委托</param> /// <returns>True/False</returns> static void Contains(Program program) { Console.WriteLine("判断给定DataTable中是否存在某个字段值符合给定条件的记录"); bool flg = ExMethod.Contains<String>(program.LinqTable, "name", (string name) => { return name.Equals("1 Max"); }); Console.WriteLine(flg.ToString()); Console.WriteLine(); } /// <summary> /// 获取DataTable中符合某个条件的唯一记录 /// </summary> /// <param name="table">DataTable</param> /// <param name="predicate">Func委托</param> /// <returns></returns> static void SingleOrDefault(Program program) { Console.WriteLine("获取DataTable中符合某个条件的唯一记录"); DataRow row = ExMethod.SingleOrDefault<int>(program.LinqTable, "id", (int i) => { return i == 10; }); if (row != null) { foreach (var it in row.ItemArray) { Console.Write(it + " "); } Console.WriteLine(); } Console.WriteLine(); } /// <summary> /// 添加指定的列 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="columnFiled"></param> static void AddColumnFiled(Program program) { Console.WriteLine("添加指定的列"); ExMethod.AddColumnFiled<string>(program.LinqTable, "sex"); Console.WriteLine(program.LinqTable.Columns.Count); Console.WriteLine(); } /// <summary> /// 添加指定的列并且附默认值 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="columnFiled"></param> /// <param name="value"></param> static void AddColumnFiledTwo(Program program) { Console.WriteLine("添加指定的列并且附默认值"); ExMethod.AddColumnFiled<string>(program.LinqTable, "job", "码农"); for (int i = 0; i < program.LinqTable.Rows.Count; i++) { DataRow row = program.LinqTable.Rows[i]; foreach (var it in row.ItemArray) { Console.Write(it + " "); } Console.WriteLine(); } Console.WriteLine(); } /// <summary> /// DataTable中某个字段具有最大值的记录 /// </summary> /// <param name="program"></param> static void Max(Program program) { Console.WriteLine("DataTable中某个字段具有最大值的记录"); DataRow row = ExMethod.Max<float>(program.LinqTable.Rows, () => { return "salary"; }); foreach (var it in row.ItemArray) { Console.Write(it + " "); } Console.WriteLine(); } #region 录入数据 static void AddData(Program program) { program.AddNewRow(1, " 小瀚"); program.AddNewRow(2, " 小明"); program.AddNewRow(3, " 小杰"); program.AddNewRow(4, " 小黄"); program.AddNewRow(5, " 小白"); program.AddNewRow(6, " 小李"); program.AddNewRow(7, " 张三"); program.AddNewRow(8, " 李四"); program.AddNewRow(9, " 帅哥"); program.AddNewRow(10, " CC"); } #endregion }
以下是扩展方法
public static class ExMethod { /// <summary> /// 给DataTable中的每条记录执行某个操作 /// </summary> /// <param name="table"></param> /// <param name="action"></param> public static void ForEach(this DataTable table, Action<DataRow> action) { for (int i = 0; i < table.Rows.Count; i++) { DataRow current = table.Rows[i]; action(current); } } /// <summary> /// 从DataTable中获取某个字段组成的集合 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="name"></param> /// <returns></returns> public static IEnumerable<T> Select<T>(this DataTable dt, string name) { DataColumnCollection columns = dt.Columns; IList<T> iList = new List<T>(dt.Rows.Count); if (!columns.Contains(name)) return iList; for (var i = 0; i < dt.Rows.Count; i++) { iList.Add((T)dt.Rows[i][name]); } return iList; } /// <summary> /// 获取DataTable中某个字段符合给定条件的处理过的集合 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="name"></param> /// <param name="func"></param> /// <returns></returns> public static IEnumerable<T> Select<T>(this DataTable dt, string name, Func<T, T> func) { DataColumnCollection columns = dt.Columns; IList<T> iList = new List<T>(); if (!columns.Contains(name)) return iList; for (int i = 0; i < dt.Rows.Count; i++) { iList.Add(func((T)dt.Rows[i][name])); } return iList; } /// <summary> /// 判断给定DataTable中是否存在某个字段值符合给定条件的记录 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="name"></param> /// <param name="func"></param> /// <returns></returns> public static bool Contains<T>(this DataTable dt, string name, Func<T, bool> func) { DataColumnCollection columns = dt.Columns; if (!columns.Contains(name)) return false; foreach (DataRow row in dt.Rows) { if (func((T)row[name])) { return true; } } return false; } /// <summary> /// 获取DataTable中符合某个条件的唯一记录 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="name"></param> /// <param name="func"></param> /// <returns></returns> public static DataRow SingleOrDefault<T>(this DataTable dt, string name, Func<T, bool> func) { DataRow result = null; long count = 0; for (int i = 0; i < dt.Rows.Count; i++) { DataRow current = dt.Rows[i]; if (func((T)current[name])) { count++; result = current; } } switch (count) { case 0: return null; case 1: return result; } return result; } /// <summary> /// 添加指定的列 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="columnFiled"></param> public static void AddColumnFiled<T>(this DataTable dt, string columnFiled) { if (!string.IsNullOrWhiteSpace(columnFiled)) { dt.Columns.Add(columnFiled, typeof(T)); } } /// <summary> /// 添加指定的列并且附默认值 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <param name="columnFiled"></param> /// <param name="value"></param> public static void AddColumnFiled<T>(this DataTable dt, string columnFiled, T value) { if (!string.IsNullOrWhiteSpace(columnFiled)) { dt.Columns.Add(columnFiled, typeof(T)); for (int i = 0; i < dt.Rows.Count; i++) { DataRow current = dt.Rows[i]; current[columnFiled] = value; } } } /// <summary> /// DataTable中某个字段具有最大值的记录 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="collection"></param> /// <param name="selector"></param> /// <returns></returns> public static DataRow Max<T>(this DataRowCollection collection, Func<string> func) { string name = func(); DataTable dt = collection[0].Table; DataColumnCollection columns = dt.Columns; if (!columns.Contains(name)) return null; Comparer<T> comparer = Comparer<T>.Default; DataRow result = null; T value = default(T); foreach (DataRow row in collection) { if (comparer.Compare(value, (T)row[name]) < 0) { value = (T)row[name]; result = row; } } return result; } }
以下是参考别人Deno写的几个扩展方法,如有不对,请多多指教!
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