Use IComparer to sort by different properties : CompareTo « Data Structure « VB.Net






Use IComparer to sort by different properties

Use IComparer to sort by different properties
Imports System
Imports System.Collections


Public Class MainClass

  Shared Sub Main()
    Dim e1 As New Employee("E1", 50000)
    Dim e2 As New Employee("E2", 60000)
    Dim e3 As New Employee("E3", 20000)
    Dim e4 As New Employee("E4", 1)
    Dim theEmployees() As Employee = {e1, e2, e3, e4}
    
    Array.Sort(theEmployees)
    
    Console.WriteLine("Sort by Salary")
    
    Dim SortingByName As SortByName = New SortByName()

    Dim aEmployee As Employee


    For Each aEmployee In theEmployees
      Console.WriteLine(aEmployee.TheName & " has yearly salary $" & FormatNumber(aEmployee.Salary))
    Next

    Console.WriteLine("Sort by Name")

    Array.Sort(theEmployees, SortingByName)
    
    
    For Each aEmployee In theEmployees
      Console.WriteLine(aEmployee.TheName & " has yearly salary $" & FormatNumber(aEmployee.Salary))
    Next
  End Sub
End Class


Public Class SortByName
  Implements IComparer
  Public Function CompareTo(ByVal firstEmp As Object, ByVal _
  secondEmp As Object) As Integer Implements IComparer.Compare
    Dim temp1 As Employee = CType(firstEmp, Employee)
    Dim temp2 As Employee = CType(secondEmp, Employee)
    Return String.Compare(temp1.TheName, temp2.TheName)
  End Function
End Class
Public Class Employee
  Implements IComparable
  Private m_Name As String
  Private m_Salary As Decimal

  Public Sub New(ByVal theName As String, ByVal curSalary As Decimal)
    m_Name = theName
    m_Salary = curSalary
  End Sub
  Public Function CompareTo(ByVal AnEmployee As Object) As Integer _
  Implements IComparable.CompareTo
    If CType(AnEmployee, Employee).Salary < Me.Salary Then
      Return -1
    ElseIf CType(AnEmployee, Employee).Salary = Me.Salary Then
      Return 0
    ElseIf CType(AnEmployee, Employee).Salary > Me.Salary Then
      Return 1
    End If
  End Function
  Public ReadOnly Property TheName() As String
    Get
      Return m_Name
    End Get
  End Property
  Public ReadOnly Property Salary() As Decimal
    Get
      Return MyClass.m_Salary
    End Get
  End Property
End Class

           
       








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