How to add regex matches to list in VB.net - regex

Question

I am having a Regex and I want the matches to be added to my previous List. The list (called "Items") has already some entries. (It got the entries from a listbox1 and added is now a datasource of the listbox1)
This is my source:
Dim Items As List(Of String)
<some other code here>
For Each Bam As Match In Treffer
If hashtagz = False Then
ListBox1.Items.Add(Bam.Groups(1).ToString)
ElseIf hashtagz = True And FirstHashtags = True Then
ListBox1.Items.Add(Bam.Groups(1).ToString)
ElseIf hashtagz = True And FirstHashtags = False Then
Items.Add(Bam.Groups(1).ToString)
Console.WriteLine(Bam.Groups(1).ToString)
End If
Next
The last part is important (the last if loop with hashtagz = true and Firsthashtags = False)
I also added the console.writeline to see what is going on. In the console, I get all the new scraped and correct information. In the Items list however, I just get a duplicate of what has been already stored in there instead of adding and updating my list with the new regex matches.
edit Additional information: The whole if condition is in a timer, so it runs again and again. At first it will add entries to a listbox. Then (now important!) it will do the Items.Add(Bam.Groups(1).ToString). It seems to add the new entries the FIRST time THAT part of the code gets executed, but after it is being run trhough again trhough a timer, it will just add the previous entries again and again

Answer 1

Dim Items As New List(Of String)
Dim hashtagz As Boolean
Dim FirstHashtags As Boolean
' Other code here
For Each Bam As Match In Treffer
Select Case True
Case Not hashtagz
ListBox1.Items.Add(Bam.Groups(1).ToString)
Case FirstHashtags
ListBox1.Items.Add(Bam.Groups(1).ToString)
Case Items.Contains(Bam.Groups(1).ToString)
' Already Exists
Case Else
Items.Add(Bam.Groups(1).ToString)
Console.WriteLine(Bam.Groups(1).ToString)
End Select
Next

Answer 2

After using more than 7 hours today (and a few hours yesterday, I am a newbie in VB) of testing, going through my code and building in some outputs to see where the problem is...
My concept is correct, there are no logical errors in the flow of my programm, as one can see from the console.writeline(Bam.Groups(1).ToString . I tested everything and ended up putting in a richtextbox and its like this now
For Each Bam As Match In Treffer
If hashtagz = False Then
ListBox1.Items.Add(Bam.Groups(1).ToString)
ElseIf hashtagz = True And FirstHashtags = True Then
ListBox1.Items.Add(Bam.Groups(1).ToString)
ElseIf hashtagz = True And FirstHashtags = False Then
Items.Add(Bam.Groups(1).ToString)
RichTextBox1.Text = RichTextBox1.Text + Bam.Groups(1).ToString & vbNewLine
End If
Next
The adding procedure seems to be looking correct with the richtextbox, but when I want to add to the Items list, it just gives out the duplicates of the previous entries instead of adding to it. The .add seems to work only the FIRST time running through that line of code, after the second time it just gives out the duplicate of the entries.
I am still trying to figure out WHY that is and I will trying to understand the posts above. Maybe someone else has also an explanation, jsut in case the others were wrong
Edit I have been experimenting still with all this, I have a function that grabs the last entry of my item list and prints out a part of it. When I do that, the print seems correct and updated. So it seems like the list IS actually being updated somehow since the "getting a part of the latest entry of list" is working and always updated. But when I want to show or save the content of the item list, that's when I get the duplicates and the updated and newest entries are not being shown!

Answer 3

Alright guys, I am back again after testing.
The code I posted above was correct. The real reason behind the mistake was in a few other parts of the code, which resulted in partially duplicated output of the entries of the list etc.
I lost track of the variables and the procedures my program was doing. Any hints or tips for me on how to keep track of the code on what it does and having everything in mind or how to properly structure code etc. so that I won't get lost again and again in the code?
This case can be closed, sorry for the inconvenience.