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How to VB.NET ArrayList
With the Array list you can add elements to your array dynamically and it accepts null as a valid value and also allows duplicate elements. Normally Collection class allow you to access an item using either a numeric index or a String key, but ArrayList allows only a numeric index. ArrayList is flexible because we can add items without any size information.
Important functions from ArrayList Object
Add : Add Items in an ArrayList
Insert : Insert Items to a specified position in an ArrayList
Remove : Remove an Item from ArrayList
RemoveAt: remove an item from a specified position
Sort : Sort Items in an ArrayList
How to add Items in an ArrayList ?
Syntax : ArrayList.add(Item) Item : The Item to be add the ArrayList |
Dim ItemList As New ArrayList()
ItemList.Add("Item4")
How to Insert Items in an ArrayList ?
Ø Syntax : ArrayList.insert(index,item).
Ø index : The position of the item in an ArrayList.
Ø Item : The Item to be add the ArrayList.
ItemList.Insert(3, "item6")
How to remove an item from arrayList ?
Syntax : ArrayList.add(Item) Item : The Item to be add the ArrayList |
ItemList.Remove("item2")
How to remove an item in a specified position from an ArrayList ?
Syntax : ArrayList.RemoveAt(index) index : the position of an item to remove from an ArrayList |
ItemList.RemoveAt(2)
How to sort ArrayList ?
Syntax : ArrayListSort() |
From the following Visual Basic source code you can see some important operations from an ArrayList Object
When you execute this program , it add five items in the arraylist and displays using a for loop statement. Then again one more item inserted in the third position , and then sort all items. Next it remove the item1 and also remove the item from the third position . Finally it shows the existing items.
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles Button1.Click
Dim i As Integer
Dim ItemList As New ArrayList()
ItemList.Add("Item4")
ItemList.Add("Item5")
ItemList.Add("Item2")
ItemList.Add("Item1")
ItemList.Add("Item3")
MsgBox("Shows Added Items")
For i = 0 To ItemList.Count - 1
MsgBox(ItemList.Item(i))
Next
'insert an item
ItemList.Insert(3, "Item6")
'sort itemms in an arraylist
ItemList.Sort()
'remove an item
ItemList.Remove("Item1")
'remove item from a specified index
ItemList.RemoveAt(3)
MsgBox("Shows final Items the ArrayList")
For i = 0 To ItemList.Count - 1
MsgBox(ItemList.Item(i))
Next
End Sub
End Class
