Getting Started
Okay now that we cleared that up, it is now time to start coding the UI. Open VS (or VB Express) and create a VB Windows Forms (sorry, I'll make another tutorial for WPF). Name it "Counter". This is a simple form which will count to 30 on a thread and print it to a TextBox.
Drag two Buttons and a Multi-line TextBox to your form. To get a multi-line TextBox, you must set its multi-line property to True. Make sure the TextBox fills up the bottom half of the window. Name the TextBox as "CounterBox" and rename the Button1 as "CountBtn". Rename the second button as "CountAsyncBtn". Don't forget to make CountBtn's Text value as "Count" and other button as "Count Async" or "Count Threaded" (your choice).
Double click the "Count" button. You are now in the Button's Click_Event. Add the following code to its Click_Event:
'The following is an example of counting without a thread. For i as Integer = 0 to 100 Application.DoEvents() 'This simulates a delay but it really keeps the UI from freeze so you can see the numbers go up. CounterBox.AppendText(i.ToString() + vbNewLine) Next
You make get some compiler errors at this point but don't worry. To fix them, add the following to the top of the file:
Imports System.Windows.Forms 'Only add this if its not already there Imports System.Threading 'Add this for later
If you like, you can stop and run the count at this point and see how it counts. Once thats finished, we can continue with the threaded example.
Double click the CountAsyncBtn and add the following code:
'Normally, threads require you to pass code in a separate function but I am using a new technique called anonymous methods.
Dim thr As New Thread(Sub()
For i as Integer = 0 to 100
Thread.Sleep(100) 'This adds a simple delay so you can see it count and also to keep it from eating up memory.
Me.Invoke(Sub()
'Same with the threads, it requires a function delegate but instead, I will pass a anonymous method.
CounterBox.AppendText(i.ToString() + vbNewLine)
End Sub)
Next
End Sub)
thr.IsBackground = True
thr.Start() 'Starts the thread
With all of that code written, your form's code should look something like this:
Imports System.Windows.Forms 'Only add this if its not already there
Imports System.Threading 'Add this for later
Public Class Form1
Private Sub CountBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CountBtn.Click
For i As Integer = 0 To 100
Application.DoEvents() 'This simulates a delay but it really keeps the UI from freeze so you can see the numbers go up.
CounterBox.AppendText(i.ToString() + vbNewLine)
Next
End Sub
Private Sub CountAsyncBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CountAsyncBtn.Click
'Normally, threads require you to pass code in a separate function but I am using a new technique called anonymous methods.
Dim thr As New Thread(Sub()
For i As Integer = 0 To 100
Thread.Sleep(100) 'This adds a simple delay so you can see it count and also to keep it from eating up memory.
Me.Invoke(Sub()
'Same with the threads, it requires a function delegate but instead, I will pass a anonymous method.
CounterBox.AppendText(i.ToString() + vbNewLine)
End Sub)
Next
End Sub)
thr.IsBackground = True
thr.Start() 'Starts the thread
End Sub
End Class
You should see it counting from a thread.
Downloads
You can download my sample project from here. It requires Visual Studio 2010 (or VB Express 2010).
Counter.zip (11.45K)
Number of downloads: 250
Good luck with your many programming adventures.
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