Use ArrayList.Contains to check if a object already exists : ArrayList « Collections « VB.Net Tutorial

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VB.Net Tutorial » Collections » ArrayList 
8.11.7.Use ArrayList.Contains to check if a object already exists
Imports System.Collections
Structure Person
    Dim strLastName As String
    Dim strFirstName As String
    Dim strPhone As String
    Dim strEMail As String
End Structure


public class Test
   public Shared Sub Main
        Dim alPersons As New ArrayList
        Dim udtPerson As New Person

        'Add the first person.
        With udtPerson
            .strLastName = "S"
            .strFirstName = "J"
            .strPhone = "5"
            .strEMail = "j@s.com"
        End With
        alPersons.Add(udtPerson)

        'Add the second person.
        With udtPerson
            .strLastName = "J"
            .strFirstName = "S"
            .strPhone = "5"
            .strEMail = "s@s.com"
        End With
        alPersons.Add(udtPerson)

        'Create the third person.
        With udtPerson
            .strLastName = "J"
            .strFirstName = "K"
            .strPhone = "5"
            .strEMail = "k@s.com"
        End With

        'Insert the third person, but first check if they already exists.
        If Not alPersons.Contains(udtPersonThen
            alPersons.Insert(1, udtPerson)
        End If

        'Remove the first person.
        alPersons.RemoveAt(0)

        'Display the array list values.
        Console.WriteLine("The array list contains " & alPersons.Count & " elements.")
        For Each udtPerson In alPersons
            Console.WriteLine("NAME: " & udtPerson.strFirstName & " " & udtPerson.strLastName)
        Next udtPerson



   End Sub
End class
The array list contains 2 elements.
NAME: K J
NAME: S J
8.11.ArrayList
8.11.1.Add user defined object to ArrayList
8.11.2.Add different data types to ArrayList
8.11.3.Use ArrayList to store objects
8.11.4.Use For Each to loop through the ArrayList
8.11.5.Convert ArrayList to array
8.11.6.Use DirectCast to convert ArrayList to array
8.11.7.Use ArrayList.Contains to check if a object already exists
8.11.8.Remove element in an ArrayList by index
8.11.9.Sort the values in ArrayList using the default comparer and a custom comparer that reverses the sort order.
8.11.10.Determine the index of the first occurrence of a specified element.
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