如何从Linq查询中提取结果？

class Program { static void Main(string[] args) { MyDatabaseEntities entities = new MyDatabaseEntities(); var result = from c in entities.Categories join p in entities.Products on c.ID equals p.IDCategory group p by c.Name into g select new { Name = g.Key, Count = g.Count() }; Console.WriteLine(result.ToString()); Console.ReadLine(); } } 

如何从结果集中提取值，以便我可以使用它们？

Answer 1

 foreach (var item in result) { var name = item.Name; var count = item.Count; ... } 

这只能在LINQ查询所在的同一方法内部工作，因为编译器只会知道LINQ select使用的匿名对象类型（ new { } ）中可用的属性。

如果将LINQ查询返回给调用方法，并且希望以上面显示的方式访问它，则必须定义显式类型并在LINQ查询中使用它：

 class NameCountType { public string Name { get; set; } public int Count { get; set; } } ... return from ... in ... ... select new NameCountType { Name = ..., Count = ..., }; 

Answer 2

例如：

 foreach (var x in result) { Console.WriteLine(xcName); } 

Answer 3

  var results = (from myRow in ds.Tables[0].AsEnumerable() where myRow.Field("UserName") == "XXX" select myRow).Distinct(); foreach (DataRow dr in results) UserList += " , "+dr[0].ToString();