Visual Basic .NET/IDisposable

The IDisposable Interface

Basics

The IDisposable interface is implemented when an object needs to be "cleaned up" after use. If an object has a "Dispose" method, then it needs to be cleaned up after use.

The easiest way to clean up this sort of object is by using the VB keyword "Using".

    Using f As New Form
        f.Show
    End Using

When an IDisposable object is a form-level variable, it should be disposed in the Form_Closed event.

    Public Class Form1
        Private mfrmChild As Form
        Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
            mfrmChild = New Form
            mfrmChild.Text = "Child"
            mfrmChild.Show()
        End Sub
        Private Sub frmMain_FormClosed(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosedEventArgs) Handles Me.FormClosed
            mfrmChild.Dispose()
        End Sub
    End Class

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