Visual Basic Loop and Display one line at a time - vb.net

Question

I'm using visual studios 2008, VB9 and I am trying to write an app that basically performs calculations on a set of data input by a user. During the calculations, I want to display the data at each step, and have it retained in the display area on the GUI (not overwritten by the next data being displayed).
For example:
UserInput = 1
Do
UserInput += 1
OutputLabel.Text = "UserInput " & UserInput
Loop Until UserInput = 5
and the output would look like
UserInput 1
UserInput 2
UserInput 3
UserInput 4
UserInput 5
I tried this, and other loop structures and can't seem to get things right. The actual app is a bit more sophisticated, but the example serves well for logical purposes.
Any tips are welcome, thanks!

Answer 1

This is the simple version:
Dim delimiter as String = ""
For UserInput As Integer = 1 To 5
OutputLabel.Text &= String.Format("{0}UserInput {1}", delimiter, UserInput)
delimiter = " "
Next
However, there are two problems with it and others like it (including every other answer given so far):
It creates a lot of extra strings
Since it's in a loop the label won't be able to process any paint events to update itself until you finish all of your processing.
So you may as well just do this:
Dim sb As New StringBuilder()
Dim delimiter As String = ""
For UserInput As Integer = 1 To 5
sb.AppendFormat("{0}UserInput {1}", delimiter, UserInput)
delimiter = " "
Next
OutputLabel.Text = sb.ToString()
And if you really want to have fun you can just do something like this (no loop required!):
OutputLabel.Text = Enumerable.Range(1, 5).Aggregate(Of String)("", Function(s, i) s & String.Format("UserInput {0} ", i))

Answer 2

You need to concatenate the value in OutputLabel.Text.
OutputLabel.Text &= "UserInput " & UserInput
You might also want to reset it before the loop: OutputLabel.Text = ""

Answer 3

If you need an iterated index you can try something like the following
For I As Integer = 1 To 5
If I > 1 Then OutputLabel.Text &= " "
OutputLabel.Text &= "UserInput " & I.ToString()
End For
If you have user inputs in a collection, you might better be served by using ForEach loop.

Answer 4

Do you need to do it in a GUI? If it is simply processing and putting out rows like that, maybe you should consider a console application, in which case it becomes REALLY easy, in simply calling
Console.WriteLine("my string")

Answer 5

All of these ways actually work really well but the one that fit my situation the best was this:
Do
Dim OutputString as String
Application.DoEvents() 'to make things paint actively
UserInput += 1
OutputString = String.Format("{0}", UserInput)
ListBox.Items.Add(OutputString)
Loop Until UserInput = 5
I changed things to a listbox but tried this same method with textboxes and labels, with some tweaks, they all worked very well. Thanks for all your help!

Answer 6

I'd use a more appropriate control, like richtextbox
Dim UserInput As Integer = 0
Const userDone As Integer = 5
RichTextBox1.Clear()
Do
RichTextBox1.AppendText(String.Format("User input {0:n0} ", UserInput))
RichTextBox1.AppendText(Environment.NewLine)
RichTextBox1.Refresh() 'the data at each step
UserInput += 1
Loop Until UserInput = userDone