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Arraylist in Visual Basic.net

Can I get an example on how to do something like Vector or ArrayList in Visual Basic.NET?

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6 answers 


Dim list As New ArrayList

or (equivalently):

Dim list As ArrayList = New ArrayList


If you want a generic list (very similar to ArrayList):

Dim list As New List(Of String)

Also see ArrayList and Documentation List .

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Try to run



Dim list As New ArrayList()
list.Add("hello")
list.Add("world")
For Each cur As String in list
  Console.WriteLine(cur)
Next
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Module Module1

    Sub Main()
        Dim al As New ArrayList()
        al.Add("1")
        al.Add("2")
        al.Add("3")
    End Sub

End Module
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If you are using VB10 you should use the following syntax.

Dim list As New List(Of Integer) From { 1, 2, 3, 4, 5 }
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Add values

Dim list As New ArrayList
list.Add("One")
list.Add("Two")
list.Add("Three")

Parameter example

Module Module1

    Sub Main()
    ' Create an ArrayList and add two elements to it.
    Dim list As New ArrayList
    list.Add(5)
    list.Add(7)
    ' Use ArrayList as an argument to the method.
    Example(list)
    End Sub

    ''' <summary>
    ''' Receives ArrayList as argument.
    ''' </summary>
    Private Sub Example(ByVal list As ArrayList)
    Dim num As Integer
    For Each num In list
        Console.WriteLine(num)
    Next
    End Sub

End Module

Output

5 7

AddRange

Module Module1

    Sub Main()
    ' Create an ArrayList and add two elements.
    Dim list1 As New ArrayList
    list1.Add(5)
    list1.Add(7)
    ' Create a separate ArrayList.
    Dim list2 As New ArrayList
    list2.Add(10)
    list2.Add(13)
    ' Add this ArrayList to the other one.
    list1.AddRange(list2)
    ' Loop over the elements.
    Dim num As Integer
    For Each num In list1
        Console.WriteLine(num)
    Next
    End Sub

End Module

Output

5 7 10 13

Count, Clear

Module Module1

    Sub Main()
    ' Add two elements to the ArrayList.
    Dim list As New ArrayList
    list.Add(9)
    list.Add(10)
    ' Write the Count.
    Console.WriteLine(list.Count)
    ' Clear the ArrayList.
    list.Clear()
    ' Write the Count again.
    Console.WriteLine(list.Count)
    End Sub

End Module

Output

20

Add, remove items

Module Module1

    Sub Main()
    ' Create an ArrayList and add three strings to it.
    Dim list As New ArrayList
    list.Add("Dot")
    list.Add("Net")
    list.Add("Perls")
    ' Remove a string.
    list.RemoveAt(1)
    ' Insert a string.
    list.Insert(0, "Carrot")
    ' Remove a range.
    list.RemoveRange(0, 2)
    ' Display.
    Dim str As String
    For Each str In list
        Console.WriteLine(str)
    Next
    End Sub

End Module

Output

Perls

TryCast

Module Module1

    Sub Main()
    ' Create a new ArrayList.
    Dim list As New ArrayList
    list.Add("man")
    list.Add("woman")
    list.Add("plant")
    ' Loop over the ArrayList with a For loop.
    Dim i As Integer
    For i = 0 To list.Count - 1
        ' Cast to a string.
        Dim str As String = TryCast(list.Item(i), String)
        Console.WriteLine(str)
    Next i
    End Sub

End Module

Output

man woman Plant

GetRange

Module Module1

    Sub Main()
    ' Create new ArrayList.
    Dim list1 As New ArrayList
    list1.Add("fish")
    list1.Add("amphibian")
    list1.Add("bird")
    list1.Add("plant")
    ' Create a new ArrayList and fill it with the range from the first one.
    Dim list2 As New ArrayList
    list2 = list1.GetRange(2, 2)
    ' Loop over the elements.
    Dim str As String
    For Each str In list2
        Console.WriteLine(str)
    Next
    End Sub

End Module

Output

bird Plant,

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You can use this:

Dim a As New ArrayList()
a.Add("Item1")
a.Add("Item2")
a.Add("Item3")
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