2013-05-05 61 views
1

我有下面有3个重要领域LINQ GROUP BY和最大使用条款

public class Employee 
{ 
    public string Name 
    { 
     get; 
     set; 
    } 

    public string Department 
    { 
     get; 
     set; 
    } 

    public double Salary 
    { 
     get; 
     set; 
    } 
} 

我有这样的员工列表Employee类。我想从他/她的部门的工资最高的各部门 中找到姓名员工。

我写了下面的查询,但它不工作。

List<Employee> list = new List<Employee>(); 
     list.Add(new Employee { Name="Hemant",Salary=10,Department="PTS"}); 
     list.Add(new Employee { Name = "Gunjan", Salary = 11, Department = "PTS" }); 
     list.Add(new Employee { Name = "Akshay", Salary = 8, Department = "PTS" }); 
     list.Add(new Employee { Name = "Omkar", Salary = 10, Department = "EBG" }); 
     list.Add(new Employee { Name = "Hemant1", Salary = 14, Department = "EBG" }); 

     var query1 = from e in list 
        group e by e.Department into g 
        select new { Dept = g.Key,MaxSal = g.Max((e) => e.Salary)}; 

     foreach (var item in query1) 
     { 
      Console.WriteLine("Department : " + item.Dept + " : " + " Salary is : " + item.MaxSal);     
     } 

但上面的一段代码不起作用,我无法选择员工姓名。我想我必须使用升序/降序条款并选择第一条或最后一条记录。但我无法弄清楚。有人可以帮忙吗?

问候, 与Hemant斯赫拉尔

回答

3

是的,你应该OrderByDescending然后拿到First

var query1 = list.GroupBy(x => x.Department) 
       .Select(g => g.OrderByDescending(x => x.Salary).First()); 

下面是控制台代码:

foreach (var item in query1) 
{ 
    string output = string.Format("Deparment: {0}, Name: {1}, Max Salaray: {2}", 
            item.Department, item.Name, item.Salary 
     ); 

    Console.WriteLine(output); 
} 
+0

非常感谢我期待的。现在我试图将其转换为等价的LINQ查询:) – user2243747 2013-05-05 06:10:58

+0

@ user2243747:您不需要这样做,我总是觉得lambda语法更简单易用。在底层,linq语法将被转换为lambda语法。 – 2013-05-05 06:16:48