linq对datatable多列排序,该怎么处理

linq对datatable多列排序

C# code

       private void TestSortLinq()        {            string idColumnName = "ID";            string nameColumnName = "Name";            string phoneColumnName="Phone";            string addressColumnName="Address";            DataTable testDT = new DataTable();            testDT.Columns.AddRange(                new DataColumn[] {                new DataColumn(idColumnName,typeof(System.String)),                new DataColumn(nameColumnName,typeof(System.String)),                new DataColumn(phoneColumnName,typeof(System.String)),                new DataColumn(addressColumnName,typeof(System.String))});                        for (int i = 0; i < 20; i++)            {                Random _rd = new Random(i);                DataRow row = testDT.NewRow();                row[idColumnName] = idColumnName + _rd.Next(i).ToString();                row[nameColumnName] = nameColumnName + _rd.Next(i).ToString();                row[phoneColumnName] = phoneColumnName + _rd.Next(i).ToString();                row[addressColumnName] = addressColumnName + _rd.Next(i).ToString();                testDT.Rows.Add(row);            }            testDT.TableName="testDT";            IEnumerable<DataRow> rows = from p in testDT.AsEnumerable()                                        select p;            #region 没问题            rows = rows.CopyToDataTable().AsEnumerable().OrderBy(s =>                decimal.Parse(Regex.Match(s[idColumnName].ToString(), @"\d+").Value));            testDT = rows.CopyToDataTable();            #endregion            #region 有问题            rows = rows.CopyToDataTable().AsEnumerable().OrderBy(s => new            {                //虽然现在这里只写了两个，但是有可能是三个或者是四个或者是一个，请问这里怎么写成动态的orderby语句                id = decimal.Parse(Regex.Match(s[idColumnName].ToString(), @"\d+").Value),                name = decimal.Parse(Regex.Match(s[nameColumnName].ToString(), @"\d+").Value)             });            testDT = rows.CopyToDataTable();            #endregion        }

大家看下我的代码就知道我说的什么了：1是为什么第二种写法会报错，2,如何写一个动态的orderby语句

[解决办法]
var list = source.OrderBy(...);

if (条件1)
list = list.ThenBy(...);
if (条件2)
list = list.ThenBy(...);
...
[解决办法]

C# code

 rows = rows.CopyToDataTable().AsEnumerable()    .OrderBy(s =>decimal.Parse(Regex.Match(s[idColumnName].ToString(), @"\d+").Value))    .ThenBy(s =>decimal.Parse(Regex.Match(s[nameColumnName].ToString(), @"\d+").Value));
[解决办法]
用 var 关键字！！！

var query = dt.AsEnumerable().OrderBy(r => 1);

OrderBy完是 OrderedEnumerableRowCollection<T>
[解决办法]
给你贴个main函数，通过设置Flag和str_c来动态指定排序的列，你试试看对不对
注:"ID2"大于"ID10"。。。郁闷了我很久。。。
C# code
        static void Main(string[] args)        {            string idColumnName = "ID";            string nameColumnName = "Name";            string phoneColumnName = "Phone";            string addressColumnName = "Address";            DataTable testDT = new DataTable();            testDT.Columns.AddRange(                new DataColumn[] {                new DataColumn(idColumnName,typeof(System.String)),                new DataColumn(nameColumnName,typeof(System.String)),                new DataColumn(phoneColumnName,typeof(System.String)),                new DataColumn(addressColumnName,typeof(System.String))});            for (int i = 0; i < 20; i++)            {                Random _rd = new Random(i);                DataRow row = testDT.NewRow();                row[idColumnName] = idColumnName + _rd.Next(i).ToString();                row[nameColumnName] = nameColumnName + _rd.Next(i).ToString();                row[phoneColumnName] = phoneColumnName + _rd.Next(i).ToString();                row[addressColumnName] = addressColumnName + _rd.Next(i).ToString();                testDT.Rows.Add(row);            }            var query = from s in testDT.AsEnumerable() orderby new orderClass() { C1 = get_c1(s), C2 = get_c2(s), C3 = get_c3(s), C4 = get_c4(s) } select s;            foreach (var r in query)            {                Console.Write(r[0].ToString() + "   ");                Console.Write(r[1].ToString() + "   ");                Console.Write(r[2].ToString() + "   ");                Console.Write(r[3].ToString() + "   ");                Console.WriteLine();            }            Console.ReadKey();        }        static private bool c1Flag = true;//控制是否依orderClass的第一项来排序        static private bool c2Flag = false;        static private bool c3Flag = false;        static private bool c4Flag = true;        static private string str_c1 = "ID";//控制排序的第一项对应的 属性名称        static private string str_c2 = "Name";        static private string str_c3 = "Phone";        static private string str_c4 = "Address";        static private string get_c4(DataRow s)        {            //在函数内部进行判断,控制返回值            if (c4Flag)            {                return s[str_c4].ToString();            }            else            {                return "";            }        }        static private string get_c3(DataRow s)        {            if (c3Flag)            {                return s[str_c3].ToString();            }            else            {                return "";            }        }        static private string get_c2(DataRow s)        {            if (c2Flag)            {                return s[str_c2].ToString();            }            else            {                return "";            }        }        static private string get_c1(DataRow s)        {            if (c1Flag)            {                return s[str_c1].ToString();            }            else            {                return "";            }        }        class orderClass : IComparable<orderClass>        {            //c1, c2, c3, c4表示排序的优先顺序，当然，可以有c5，c6等等            private string c1, c2, c3, c4;            public string C4            {                get { return c4; }                set { c4 = value; }            }            public string C3            {                get { return c3; }                set { c3 = value; }            }            public string C2            {                get { return c2; }                set { c2 = value; }            }            public string C1            {                get { return c1; }                set { c1 = value; }            }            #region IComparable<AClass> 成员            int IComparable<orderClass>.CompareTo(orderClass p)            {                if (c1.CompareTo(p.c1) != 0)                {                    return c1.CompareTo(p.c1);                }                else if (c2.CompareTo(p.c2) != 0)                {                    return c2.CompareTo(p.c2);                }                else if (c3.CompareTo(p.c3) != 0)                {                    return c3.CompareTo(p.c3);                }                else                {                    return c4.CompareTo(p.c4);                }            }            #endregion        } 
  

 

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