linq一般用法

最一般的用法

            var rows =
                   from c in dataTrue.AsEnumerable()
                   from t in dataPre.AsEnumerable()
                   where t[0].ToString().StartsWith(c[1].ToString())
                   select new
                   {
                       ID = c[0],
                       dayTime = this.StrDateConvertDateToString(c[1].ToString()),

                       value = c[2],
                       pre1 = t[1],
                       pre2 = t[2],
                       pre3 = t[3],

                       valueu = c[3],
                       pre1u = t[4],
                       pre2u = t[5],
                       pre3u = t[6],

                       valuem = c[4],
                       pre1m = t[7],
                       pre2m = t[8],
                       pre3m = t[9],

                       valuec = c[5],
                       pre1c = t[10],
                       pre2c = t[11],
                       pre3c = t[12]
                   };
            rows = rows.Distinct();

           // rows = rows.Distinct();


            DataTable dt = new DataTable();
            dt.Columns.Add("ID", typeof(string));
            dt.Columns.Add("dayTime", typeof(string));
            dt.Columns.Add("value", typeof(string));
            dt.Columns.Add("pre1", typeof(string));
            dt.Columns.Add("pre2", typeof(string));
            dt.Columns.Add("pre3", typeof(string));


            dt.Columns.Add("valueu", typeof(string));
            dt.Columns.Add("pre1u", typeof(string));
            dt.Columns.Add("pre2u", typeof(string));
            dt.Columns.Add("pre3u", typeof(string));


            dt.Columns.Add("valuem", typeof(string));
            dt.Columns.Add("pre1m", typeof(string));
            dt.Columns.Add("pre2m", typeof(string));
            dt.Columns.Add("pre3m", typeof(string));



            dt.Columns.Add("valuec", typeof(string));
            dt.Columns.Add("pre1c", typeof(string));
            dt.Columns.Add("pre2c", typeof(string));
            dt.Columns.Add("pre3c", typeof(string));
            //插入id
            rows.ToList().ForEach(kv => dt.Rows.Add(kv.ID, kv.dayTime, kv.value, kv.pre1, kv.pre2, kv.pre3, kv.valueu, kv.pre1u, kv.pre2u, kv.pre3u, kv.valuem, kv.pre1m, kv.pre2m, kv.pre3m, kv.valuec, kv.pre1c, kv.pre2c, kv.pre3c));


            this.dg1.DataContext = null;
            this.dg1.DataContext = dt;
            this.dg1.Items.Refresh();