Replacement for thread.start() and thread.abort() - vb.net

Question

I need to display a form for some amount of time - basically a "please wait, loading" form with progress bar. When certain operation completes, I want this window to disappear. Here's my try at it:
If IsNothing(mlLabels) Or mblnIsLoading Then Exit Sub
If mstrPrinterA.Equals(Me.cmbPrinters.Text, StringComparison.OrdinalIgnoreCase) Then
Exit Sub
End If
Dim th As New Threading.Thread(AddressOf WaitPrinter)
th.Start()
If mlLabels.IsPrinterOnLine(Me.cmbPrinters.Text) Then
Me.cmbPrinters.BackColor = Drawing.Color.Green
Else
Me.cmbPrinters.BackColor = Drawing.Color.Red
End If
th.Abort()
Do While th.IsAlive
Loop
th = Nothing
mstrPrinterA = Me.cmbPrinters.Text
Private Sub WaitPrinter()
Dim fw As New FormWaiting
fw.ShowDialog()
fw = Nothing
End Sub
However, I then read that using Thread.Start() and Thread.Abort() is not considered a good practice. Is there another way I can do that?

Answer 1

Here is a simple example of what I described in my comment above. Create a WinForms project with two forms, adding a Button to Form1 and a BackgroundWorker to Form2. Add this code to Form1:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'Display a dialogue while the specified method is executed on a secondary thread.
Dim dialogue As New Form2(New Action(Of Integer)(AddressOf Pause), New Object() {5})
dialogue.ShowDialog()
MessageBox.Show("Work complete!")
End Sub
Private Sub Pause(period As Integer)
'Pause for the specified number of seconds.
Threading.Thread.Sleep(period * 1000)
End Sub
and this code to Form2:
Private ReadOnly method As [Delegate]
Private ReadOnly args As Object()
Public Sub New(method As [Delegate], args As Object())
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Me.method = method
Me.args = args
End Sub
Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
BackgroundWorker1.RunWorkerAsync()
End Sub
Private Sub BackgroundWorker1_DoWork(sender As Object, e As ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
'Execute the specified method with the specified arguments.
method.DynamicInvoke(args)
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
'Close the dialogue when the work is complete.
Close()
End Sub
Run the project and click the Button on the startup form. You'll see the dialogue displayed while the work is executed and then disappear when it's done. The dialogue is written in such a way that it can be used to invoke any method with any arguments. It's the caller that gets to define what the work to be performed is.
In this particular case, the "work" is a simple sleep but you can put anything you like in there. Just note that it is executed on a secondary thread so no direct interaction with the UI is allowed. If you need UI interaction then that could be accomplished but you'd need slightly more complex code. Note that the code as it is also does not allow for returning a result from the executed method, but you could support that fairly easily too.