DataTable是ADO.NET中用于存储数据的内存表,它包含行和列,类似于数据库中的表。要使用LINQ对DataTable进行查询,你需要将DataTable的AsEnumerable方法的结果与LINQ查询结合使用。AsEnumerable方法返回一个可枚举的DataRow集合,这样你就可以在DataTable上使用LINQ查询了。 3. 学习LINQ中的GroupBy方法,并理解其工作原理 Gro...
//2、Linq写法 最终编译器会把它转化为lamda表达式 //var result = from s in ds.Tables[0].AsEnumerable() group s by new { Year = s.Field<int>("Year"), Month = s.Field<int>("Month"), Day = s.Field<int>("Day") } into temp select temp; //DataTable 使用GroupBy方法需要注意result...
DataTable dt =newDataTable(); dt.Columns.AddRange(newDataColumn[] {newDataColumn("name",typeof(string)),newDataColumn("sex",typeof(string)),newDataColumn("score",typeof(int)) }); dt.Rows.Add(newobject[] {"张三","男",1}); dt.Rows.Add(newobject[] {"张三","男",4}); dt.Rows...
DataTable dt=newDataTable(); dt.Columns.Add("Name",typeof(System.String)); dt.Columns.Add("Value",typeof(System.Int32)); dt.Rows.Add("07",1); dt.Rows.Add("07",2); dt.Rows.Add("07",4); dt.Rows.Add("07",8); dt.Rows.Add("07",4); dt.Rows.Add("08",2); dt.Rows....
如果要使用group by的话,可以使用linq,这是C#3.0的内容。给你个示例 static void Main(string[] args) { DataTable dt = new DataTable(); dt.Columns.Add("A"); dt.Columns.Add("B"); dt.Columns.Add("C"); dt.Rows.Add("a1", "b1", "c1"); ...
DataTable中Linq查询(where,group by) 2017-06-02 15:00 −... 搬砖工Liuperit 0 4181 Linq Group by分组 2019-12-10 20:01 −1:先添加一个classOutput.cs类 public string Name { get; set; } public List<TemplateList> TemplateLists; public class TemplateList { ... ...
用LINQ（groupbyhaving）找出Datatable中的重复数据 ⽤LINQ（groupbyhaving）找出Datatable中的重复数据private void butCF_Click(object sender, RoutedEventArgs e){ if (DatagridDatatable != null && DatagridDatatable.Rows.Count > 0){ //group by ⽇期,合同号,部门 having count(记录编号)>0 找出...
//Group by in DataTable using LINQ var drAll2 = from orders in dataTable.AsEnumerable() group orders by orders.Field<string>("Diet") into g select new { ShipRegion = g.Key, Group = g }; I AM GETTING THE GROUPED ROWS IN drAll2. ...
I would like to write a Linq query to apply group-by on DataTable, which outputs the result as a DataTable.I tried this code, which returns a result as var type, but I want the result in DataTablevar query = from row in dt.AsEnumerable() group...
//使用linq to DataTable group by实现varquery =fromtindt.AsEnumerable() group t bynew{ t1 = t.Field<string>("name"), t2 = t.Field<string>("sex") } into mselectnew{ name=m.Key.t1, sex=m.Key.t2, score= m.Sum(n => n.Field<decimal>("score")) ...