Question

I found that when group by multiple values does not work well with VB.NET, but it works well with C# ,here are my code, is there something wrong with my VB.NET Code?

Here is my VB.NET code:

Sub Main
  Dim empList As New List(Of Employee)()
    empList.Add(New Employee() With _
    {.ID = 1, .FName = "John", .Age = 23, .Sex = "M"c}) 
    empList.Add(New Employee() With _
    {.ID = 2, .FName = "Mary", .Age = 25, .Sex = "F"c})
    empList.Add(New Employee() With _
    {.ID = 3, .FName = "Amber", .Age = 23, .Sex = "M"c}) 
    empList.Add(New Employee() With _
    {.ID = 4, .FName = "Kathy", .Age = 25, .Sex = "F"c})
    empList.Add(New Employee() With _
    {.ID = 5, .FName = "Lena", .Age = 27, .Sex = "F"c}) 
    empList.Add(New Employee() With _
    {.ID = 6, .FName = "Bill", .Age = 28, .Sex = "M"c})
    empList.Add(New Employee() With _
    {.ID = 7, .FName = "Celina", .Age = 27, .Sex = "F"c}) 
    empList.Add(New Employee() With _
    {.ID = 8, .FName = "John", .Age = 28, .Sex = "M"c})

Dim query = empList.GroupBy(Function(x)  New With { .Age=x.Age, .Sex= x.Sex}) _
            .Select(Function(g) New With {g.Key, g.Count()}) 

For Each employee In query 
         Console.WriteLine(employee.Count)
Next employee 
End Sub


Public Class Employee 
    Private privateID As Integer
    Public Property ID() As Integer 

        Get 
            Return privateID
        End Get 

        Set(ByVal value As Integer) 
            privateID = value
        End Set 

    End Property 

    Private privateFName As String 
    Public Property FName() As String
        Get 
            Return privateFName
        End Get 

        Set(ByVal value As String) 
            privateFName = value
        End Set 
    End Property  

    Private privateAge As Integer 
    Public Property Age() As Integer
        Get 
            Return privateAge
        End Get 

        Set(ByVal value As Integer) 
            privateAge = value
        End Set 
    End Property  

    Private privateSex As Char 
    Public Property Sex() As Char
        Get 
            Return privateSex
        End Get 

        Set(ByVal value As Char) 
            privateSex = value
        End Set 
    End Property
End Class 

the out put for employee.Count are all 1 ,it is wrong.
I try it with C# ,it works well, the result is right.

//Here are my C# code:

void Main()
{
 var empList =new List<Employee>
 {
    new Employee {ID = 1, FName = "John", Age = 23, Sex = 'M'},
    new Employee {ID = 2, FName = "Mary", Age = 25, Sex = 'F'},
    new Employee {ID = 3, FName = "Amber", Age = 23, Sex = 'M'},
    new Employee {ID = 4, FName = "Kathy", Age = 25, Sex = 'F'},
    new Employee {ID = 5, FName = "Lena", Age = 27, Sex = 'F'},
    new Employee {ID = 6, FName = "Bill", Age = 28, Sex = 'M'},
    new Employee {ID = 7, FName = "Celina", Age = 27, Sex = 'F'},
    new Employee {ID = 8, FName = "John", Age = 28, Sex = 'M'} 
 };

var query = empList.GroupBy(x => new { x.Age,  x.Sex})
                   .Select(g=>new {g.Key, Count=g.Count()}); 

foreach (var employee in query )
   Console.WriteLine(employee.Count);

 }


public class Employee
{
  public int ID {get;set;}
  public string FName {get;set;}
  public int Age {get;set;}
  public char Sex {get;set;}
 }

Answer 1

This query should work:

Dim query =
    From el In empList
    Group el By Key = new with {key el.Age, key el.Sex} 
        Into Group
    Select New  With {.key = Key,
                      .count = Group.Count()}