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[].ToString().StartsWith(c[].ToString())
                    select new
                    {
                        ID = c[],
                        dayTime = this.StrDateConvertDateToString(c[].ToString()),

                        value = c[],
                        pre1 = t[],
                        pre2 = t[],
                        pre3 = t[],

                        valueu = c[],
                        pre1u = t[],
                        pre2u = t[],
                        pre3u = t[],

                        valuem = c[],
                        pre1m = t[],
                        pre2m = t[],
                        pre3m = t[],

                        valuec = c[],
                        pre1c = t[],
                        pre2c = t[],
                        pre3c = t[]
                    };
             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();