This is my code for inserting from textfile to array to labels, but I want to be able to assign a tag property onto some of the words or perhaps use the 'Answer' which is located a line below on my text file??
IndexNo = 0
Dim FileTerm As String = "D:\soccer.txt"
Dim FileNum As Integer = FreeFile()
FileOpen(FileNum, FileTerm, OpenMode.Input)
Do
Term(IndexNo) = LineInput(FileNum)
Answer(IndexNo) = LineInput(FileNum)
IndexNo = IndexNo + 1
Loop Until EOF(FileNum)
FileClose(FileNum)
Dim Obj As Object, Count As Integer = 0
For Each Obj In Me.Controls
If TypeOf Obj Is Label Then
MyLabels(Count) = Obj
Count = Count + 1
End If
Next
Dim Random1, Random2 As Integer
Dim TempTerm, TempAnswer As Object
For Count = 0 To 15
Randomize()
Random1 = Val(Int(16 * Rnd()))
Random2 = Val(Int(16 * Rnd()))
TempTerm = Term(Random1)
Term(Random1) = Term(Random2)
Term(Random2) = TempTerm
TempAnswer = Answer(Random1)
Answer(Random1) = Answer(Random2)
Answer(Random2) = TempAnswer
Count = Count + 1
Next
For Count = 0 To 15
MyLabels(Count).Text = Term(Count)
Next
If anyone has any ideas, the help is appreciated. Thanks
Even though your question is not very clear. From what I get, you want to have some way to keep your Labels and the corresponding Term and Answers in sync.
There are many ways to do this, but I would prefer to do it as below... the perfect VB.NET way as opposed to using any legacy VB6 techniques.
First declare a class that would keep our Term and Answers in one object. This is the equivalent of Type in VB6.
Public Class TermAnswer
Public Term As String
Public Answer As String
' you may add more fields/properties here if you wish to...
End Class
Now it is easy to code our solution.
' declare a Dictionary object with Label as key and the corresponding Term and Answers as values.
Dim TermAnswers As New Dictionary(Of Label, TermAnswer)
' this is a temporary List to hold our Term and Answers read from file until we randomize them.
Dim tempTermAnswers As New List(Of TermAnswer)
' Our Labels array... yes it is this easy :)
Dim myLabels() As Label = Me.Controls.OfType(Of Label)().ToArray
' read our file into the tempTermAnswers List
Dim FileTerm As String = "D:\soccer.txt"
Using reader As New IO.StreamReader(FileTerm)
While Not reader.EndOfStream
Dim ta As New TermAnswer
ta.Term = reader.ReadLine
ta.Answer = reader.ReadLine
tempTermAnswers.Add(ta)
End While
reader.Close()
End Using
' pick Term Answers from our tempTermAnswers List randomly and add them to our TermAnswers Dictionary
' we also set our Label text here, though you can loop separately too
Dim randomNumbers As New Random
Dim tempTerm As TermAnswer, randomNumber As Integer
For Each label In myLabels
randomNumber = randomNumbers.Next(0, tempTermAnswers.Count)
tempTerm = tempTermAnswers(randomNumber)
TermAnswers.Add(label, tempTerm)
tempTermAnswers.Remove(tempTerm)
label.Text = tempTerm.Term
Next
' now you have your term answers in a Dictionary, indexed by Label.
' you can get any of them by providing a Label on your form as key and get the corresponding Term and Answer as value.
' e.g. let us list the Label Name, Term and Answer in our debug window...
For Each label In myLabels
Debug.WriteLine(label.Name & " ... " & TermAnswers(label).Term & " ... " & TermAnswers(label).Answer)
Next
Related
enter image description hereWrite a program to display 1000 8-character random user IDs in a text box after you click a button. Make sure the program verifies that none of the IDs are identical. Each userid should include a mixture of alphabetic characters and numbers.
What I have so far, which could be enough to get by as a random ID generator alone, but it does not loop 1000 times to be displayed in the label, and doesn't check for repeated ID's.
Public Class Form1
Private Sub btnGenerateRandomID_Click(sender As Object, e As EventArgs) Handles btnGenerateRandomID.Click
Dim rand As New Random
Dim char1 As String
Dim char2 As String
Dim char3 As String
Dim char4 As String
Dim char5 As String
Dim char6 As String
Dim char7 As String
Dim char8 As String
char1 = ChrW(rand.Next(Asc("A"), Asc("Z") + 1))
char2 = ChrW(rand.Next(Asc("A"), Asc("Z") + 1))
char3 = ChrW(rand.Next(Asc("A"), Asc("Z") + 1))
char4 = ChrW(rand.Next(Asc("A"), Asc("Z") + 1))
char5 = rand.Next(0, 9)
char6 = rand.Next(0, 9)
char7 = rand.Next(0, 9)
char8 = rand.Next(0, 9)
lblRandomId.Text = char1 + char2 + char3 + char4 + char5 + char6 + char7 + char8
End Sub
End Class
Thanks.
EDIT:
Public Class Form1
'Write a program to display 1000 8-character random user IDs in a text
'box after you click a button. Make sure the program verifies that none Of the IDs are identical.
'Each userid should include a mixture Of alphabetic characters And numbers.
Private Sub btnGenerateRandomID_Click(sender As Object, e As EventArgs) Handles btnGenerateRandomID.Click
Dim strChar As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
Dim rand As New Random
Dim strID As String = ""
For count_ids As Integer = 0 To 999
For count_chars As Integer = 0 To 7
strID += strChar(rand.Next(0, 62))
Next count_chars
lblRandomId.Text = strID
Next
End Sub
End Class
Here is the actual question "Q. Write a program to display 1000 8-character random user IDs in a text box after you click a button. Make sure the program verifies that none of the IDs are identical. Each userid should include a mixture of alphabetic characters and numbers.
Explain your program in your essay, with screenshots. Include a paragraph on the random number generator used in Visual Basic, and answer the question: how should the random number generator be best seeded?"
First of all, Welcome to StackOverflow,
From what i understand from your post you want to generate 1000 8 Character long Unique ID's
First of all we declare our variables
Dim Characters As String = "AZERTYUIOPQSDFGHJKLMWXCVBN0123456789" 'Declare All Characters on one string
Dim IDsList As New List(Of String) With {.Capacity = 1000} 'You can limit the capacity to 1000
Dim Id As String = ""
Dim Rand As New Random
Now we begin to genearte ID's and add them to IDsList using a nested loop
For i As Integer = 0 To 999 'This is a Zero Based Index so 999 is actually 1000
For _i As Integer = 0 To 7 'This also means 7 is 8
Id += Characters(Rand.Next(0, 36))
Next
IDsList.Add(Id)
Id = ""
Next
'You can Check for duplicates by adding this piece of code or use the next one instead
Dim NoDupesIDsList As New List(Of String)
NoDupesIDsList = IDsList.Distinct.ToList
For i As Integer = 0 To 999 'This is a Zero Based Index so 999 is actually 1000
For _i As Integer = 0 To 7 'This also means 7 is 8
Id += Characters(Rand.Next(0, 36))
Next
If not IDsList.contains(Id) then
IDsList.Add(Id)
End if
Id = ""
Next
Use a Textbox with multiline and scroll bar for better experience
Feel free to ask me anything via comments
PS: I tested my method and it's working , enjoy it !
This function will return the ASCII characters between 48 an 122. That will include some characters that are not letters or numbers but this makes the ids even more unique and simplifies the code.
The For loop builds the ids with a length of 8. Then the id is checked for uniqueness with the .Contains method. Only if it is not in the list, it is added to the list and the counter is incremented.
Private Rnd As New Random
Private Function GetListOfIDs() As List(Of String)
Dim Counter As Integer
Dim lst As New List(Of String)
Dim id As String = ""
Do While Counter < 1000
id = ""
For i = 0 To 7
id &= Chr(Rnd.Next(48, 123))
Next
If Not lst.Contains(id) Then
lst.Add(id)
Counter += 1
End If
Loop
Return lst
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lst = GetListOfIDs()
TextBox1.Text = String.Join(vbCrLf, lst)
End Sub
EDIT
As per suggestion by Caius Jard in comments I have added a solution using a HashSet. Same idea only a HashSet will not accept duplicate entries. The .Add method returns a boolean telling you if the Add was successful.
Private Function GetListOfIDs() As HashSet(Of String)
Dim hs As New HashSet(Of String)
Dim id As String = ""
Do While hs.Count < 1001
id = ""
For i = 0 To 7
id &= Chr(Rnd.Next(48, 123))
Next
If hs.Add(id) Then
Counter += 1
End If
Loop
Return hs
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim hs = BuildHashSet()
TextBox1.Text = String.Join(vbCrLf, hs)
End Sub
This method is probably more efficient because a HashSet is designed for hight performance. For 1000 items I did not notice any difference in the user interface. The text box updated immediately with both methods.
This will create the names:
Function RandomName(length As Integer) As String
Shared rnd As New Random()
Shared corpus() As Char = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".ToCharArray()
Return New String(Enumerable.Range(0, length).Select(Function(c) corpus(rnd.Next(corpus.Length))).ToArray())
End Function
Iterator Function GetUniqueNames(length As Integer, count As Integer) As IEnumerable(Of String)
Dim names As New HashSet(Of String)
For i As Integer = 0 To count
Dim name As String = RandomName(length)
While names.Contains(name)
'Potential (but unlikely) halting problem
name = RandomName(length)
End While
names.Add(name)
Yield name
Next
End Function
Dim uniqueNames = GetUniqueNames(8, 1000)
But do you really want to display 1000 of them in a single label?
lblRandomId.Text = string.Join(vbCrLf, uniqueNames)
Let's talk about your code.
Dim strChar As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
This assignment will work in your loop because a String is really an array of Char. This is why you can refer to an index in the string.
Dim rand As New Random()
The .net Random class provides a seed for Random based on system time. Only rarely would you want to provide a seed.
From the docs https://learn.microsoft.com/en-us/dotnet/api/system.random?view=netcore-3.1
CONSTRUCTORS
Random() Initializes a new instance of the Random class
using a default seed value.
Random(Int32) Initializes a new instance of the Random class, using
the specified seed value.
For count_ids As Integer = 0 To 999
A For loop is not appropriate for this problem. We only want to increment the counter if we get a unique ID. The above For loop will increment on every iteration.
Do While Counter < 1000
'Code here
Loop
Notice in my code the counter is only incremented if the ID is unique.
The following loop should work fine but above this code we need to reset strID to an empty string. Otherwise we will have a very long string.
For count_chars As Integer = 0 To 7
strID += strChar(rand.Next(0, 62))
Next count_chars
You should not update the user interface (the label) on each iteration of the loop. Repainting the screen is one of the slowest operations in code. This line will overwrite the string in the label on every iteration.
lblRandomId.Text = strID
Move the update of the UI to after both loops are complete
Your code never checks for duplicates.
Now let's fix it.
We use a List(Of T) to accumulate the IDs. The T stands for Type; in our case it is String. A List is like an array only you don't have to know ahead of time how many entries there will be. No ReDim Preserve required.
Moved Dim strID As String = "" to the beginning of the inner loop so we will get a new strID on each iteration of the outer loop.
Changed strID &= strChar(rand.Next(0, 62)). &= instead of +=. In VB.net we use the ampersand to concatenate strings although the plus sign will work. The .Next method of the Random class has an overload that takes 2 Integers. It is inclusive of the first and exclusive of the second which means (0, 62) will return numbers form 0 to 61. Your string with a length of 62 has indexes of 0 to 61.
Next we check for duplicates with the .Contains method of the List class. This method does just what you would expect. We pass the new ID to the method and it returns a Boolean telling if the string is already in the list.
If it is not in the list, we add it to the list and increment the counter. The counter is only incremented if we have a successful add.
Finally we update the user interface by using a method of the String class. the .Join method takes a separator and the list to join. The TextBox must be multiline and have scroll bars.
I changed the names of the controls so I could test it in my testing program.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lst As New List(Of String)
Dim strChar As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
Dim rand As New Random()
Dim counter As Integer
Do While counter < 1000
Dim strID As String = ""
For count_chars = 0 To 7
strID &= strChar(rand.Next(0, 62))
Next
If Not lst.Contains(strID) Then
lst.Add(strID)
counter += 1
End If
Loop
TextBox1.Text = String.Join(vbCrLf, lst)
End Sub
EDIT
The official documentation for this method can be found here.
https://learn.microsoft.com/en-us/dotnet/api/system.string.join?view=netcore-3.1
I know it will be difficult to read but just take a look. Eventually you will be able to understand it and will be using these docs a lot.
String.Join(separator, List(Of String))
The separator is what to put between the strings in the list. In our case that is vbCrLf which is a vb constant for new line. Cr = Carraiage Return and Lf = Line Feed. Other types of collections that contain strings can also use this method.
The method takes each string in the list and adds the separator. After it is done with the list it returns one long string which we display in the TextBox.
In my program, I collect bits of information on a massive scale, hundreds of thousands to millions of lines each. I am trying to limit each file I create to a certain size in order to be able to quickly open it and read the data. I am using a HashSet to collect all the data without duplicates.
Here's my code so far:
Dim Founds As HashSet(Of String)
Dim filename As String = (Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\Sorted_byKING\sorted" + Label4.Text + ".txt")
Using writer As New System.IO.StreamWriter(filename)
For Each line As String In Founds
writer.WriteLine(line)
Next
Label4.Text = Label4.Text + 1 'Increments sorted1.txt, sorted2.txt etc
End Using
So, my question is:
How do I go about saving, let's say 250,000 lines in a text file before moving to another one and adding the next 250,000?
First of all, do not use Labels to simply store values. You should use variables instead, that's what variables are for.
Another advice, always use Path.Combine to concatenate paths, that way you don't have to worry about if each part of the path ends with a separator character or not.
Now, to answer your question:
If you'd like to insert the text line by line, you can use something like:
Sub SplitAndWriteLineByLine()
Dim Founds As HashSet(Of String) 'Don't forget to initialize and fill your HashSet
Dim maxLinesPerFile As Integer = 250000
Dim fileNum As Integer = 0
Dim counter As Integer = 0
Dim filename As String = String.Empty
Dim writer As IO.StreamWriter = Nothing
For Each line As String In Founds
If counter Mod maxLinesPerFile = 0 Then
fileNum += 1
filename = IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop),
$"Sorted_byKING\sorted{fileNum.ToString}.txt")
If writer IsNot Nothing Then writer.Close()
writer = New IO.StreamWriter(filename)
End If
writer.WriteLine(line)
counter += 1
Next
writer.Dispose()
End Sub
However, if you will be inserting the text from the HashSet as is, you probably don't need to write line by line, instead you can write each "bunch" of lines at once. You could use something like the following:
Sub SplitAndWriteAll()
Dim Founds As HashSet(Of String) 'Don't forget to initialize and fill your HashSet
Dim maxLinesPerFile As Integer = 250000
Dim fileNum As Integer = 0
Dim filename As String = String.Empty
For i = 0 To Founds.Count - 1 Step maxLinesPerFile
fileNum += 1
filename = IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop),
$"Sorted_byKING\sorted{fileNum.ToString}.txt")
IO.File.WriteAllLines(filename, Founds.Skip(i).Take(maxLinesPerFile))
Next
End Sub
i want to be able to separate the values in a textbox and display the separated values in different labels using a button
this is what i want to happen:
input "Ac2O3" on textbox
Be able to separate "Ac", "2", "O", and "3".
Show the separated values in different textboxes using a button
im using visual basic 2012
im sorry im still new to this
thanks in advance!!
You can access different character of the string with the index.
Dim input As String = "Ac2O3"
Dim part1 As String = input(0) & input(1)
Dim part2 As String = input(2)
Dim part3 As String = input(3)
Dim part4 As String = input(4)
If you don't know how to handle the button event or how to display text in a textbox, that would be different questions.
This code creates a structure called Element to make the results from the function clearer - add this to your main class that the function is going to be placed in. The main function takes a string as it's input and produced a list of structures of Element as it's output. There probably are shorter ways to do this, but I'm a fairly basic programmer who likes a puzzle - hope this helps - Dont forget to accept the answer by clicking on the tick. If you have any queries please dont hesitate to ask
Structure Element
Dim symbol As String
Dim elementCount As Int16
End Structure
Function ParseFormula(ByVal compoundString As String) As List(Of Element)
Dim tempParseFormula = New List(Of Element)
Dim firstLetter As String = "[A-Z]"
Dim secondLetter As String = "[a-z]"
Dim number As String = "[0-9]"
Dim tempElementCount As String = ""
Dim maxIndex As String = compoundString.Length - 1
Dim i As Integer = 0
Dim parsedElement As New Element
While i <= maxIndex
Dim tempChar As String = compoundString(i)
Select Case True
Case tempChar Like firstLetter
parsedElement.symbol = parsedElement.symbol & tempChar
Case tempChar Like secondLetter
parsedElement.symbol = parsedElement.symbol & tempChar
Case tempChar Like number
tempElementCount = tempElementCount & tempChar
End Select
If i = maxIndex Then
If Val(tempElementCount) = 0 Then
tempElementCount = 1
End If
parsedElement.elementCount = Val(tempElementCount)
tempParseFormula.Add(parsedElement)
parsedElement.symbol = ""
parsedElement.elementCount = 0
tempElementCount = ""
Exit While
End If
i += 1
If compoundString(i) Like firstLetter Then
If Val(tempElementCount) = 0 Then
tempElementCount = 1
End If
parsedElement.elementCount = Val(tempElementCount)
tempParseFormula.Add(parsedElement)
parsedElement.symbol = ""
parsedElement.elementCount = 0
tempElementCount = ""
End If
End While
Return tempParseFormula
End Function
So I'm trying to generate a random number on button click. Now this number needs to be between two numbers that are inside my text file with various other things all separated by the "|" symbol. The number is then put into the text of a textbox which is being created after i run the form. I can get everything to work perfectly once, but as soon as i try to generate a different random number it gives me the error: "Index was out of range, must be non-negative and less than the size of the collection." Here is the main code as well as the block that generates the textbox after loading the form. As well as the contents of my text file.
Private Sub generate()
Dim newrandom As New Random
Try
Using sr As New StreamReader(itemfile) 'Create a stream reader object for the file
'While we have lines to read in
Do Until sr.EndOfStream
Dim line As String
line = sr.ReadLine() 'Read a line out one at a time
Dim tmp()
tmp = Split(line, "|")
rows(lineNum).buybutton.Text = tmp(1)
rows(lineNum).buyprice.Text = newrandom.Next(tmp(2), tmp(3)) 'Generate the random number between two values
rows(lineNum).amount.Text = tmp(4)
rows(lineNum).sellprice.Text = tmp(5)
rows(lineNum).sellbutton.Text = tmp(1)
lineNum += 1
If sr.EndOfStream = True Then
sr.Close()
End If
Loop
End Using
Catch x As Exception ' Report any errors in reading the line of code
Dim errMsg As String = "Problems: " & x.Message
MsgBox(errMsg)
End Try
End Sub
Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
rows = New List(Of duplicate)
For dupnum = 0 To 11
'There are about 5 more of these above this one but they all have set values, this is the only troublesome one
Dim buyprice As System.Windows.Forms.TextBox
buyprice = New System.Windows.Forms.TextBox
buyprice.Width = textbox1.Width
buyprice.Height = textbox1.Height
buyprice.Left = textbox1.Left
buyprice.Top = textbox1.Top + 30 * dupnum
buyprice.Name = "buypricetxt" + Str(dupnum)
Me.Controls.Add(buyprice)
pair = New itemrow
pair.sellbutton = sellbutton
pair.amount = amounttxt
pair.sellprice = sellpricetxt
pair.buybutton = buybutton
pair.buyprice = buypricetxt
rows.Add(pair)
next
end sub
'textfile contents
0|Iron Sword|10|30|0|0
1|Steel Sword|20|40|0|0
2|Iron Shield|15|35|0|0
3|Steel Shield|30|50|0|0
4|Bread|5|10|0|0
5|Cloak|15|30|0|0
6|Tent|40|80|0|0
7|Leather Armour|50|70|0|0
8|Horse|100|200|0|0
9|Saddle|50|75|0|0
10|Opium|200|500|0|0
11|House|1000|5000|0|0
Not sure what else to add, if you know whats wrong please help :/ thanks
Add the following two lines to the start of generate():
Private Sub generate()
Dim lineNum
lineNum = 0
This ensures that you don't point to a value of lineNum outside of the collection.
I usually consider it a good idea to add
Option Explicit
to my code - it forces me to declare my variables, and then I think about their initialization more carefully. It helps me consider their scope, too.
Try this little modification.
I took your original Sub and changed a little bit take a try and let us know if it solve the issue
Private Sub generate()
Dim line As String
Dim lineNum As Integer = 0
Dim rn As New Random(Now.Millisecond)
Try
Using sr As New StreamReader(_path) 'Create a stream reader object for the file
'While we have lines to read in
While sr.Peek > 0
line = sr.ReadLine() 'Read a line out one at a time
If Not String.IsNullOrEmpty(line) And Not String.IsNullOrWhiteSpace(line) Then
Dim tmp()
tmp = Split(line, "|")
rows(lineNum).buybutton.Text = tmp(1)
rows(lineNum).buyprice.Text = rn.Next(CInt(tmp(2)), CInt(tmp(3))) 'Generate the random number between two values
rows(lineNum).amount.Text = tmp(4)
rows(lineNum).sellprice.Text = tmp(5)
rows(lineNum).sellbutton.Text = tmp(1)
lineNum += 1
End If
End While
End Using
Catch x As Exception ' Report any errors in reading the line of code
Dim errMsg As String = "Problems: " & x.Message
MsgBox(errMsg)
End Try
End Sub
I'm currently using the following to read the contents of all text files in a directory into an array
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
Within the text files are only 6 lines that all follow the same format and will read something like
forecolour=black
I'm trying to then search for the word "forecolour" and retrieve the information after the "=" sign (black) so i can then populate the below code
AllDetail(numfiles).uPath = ' this needs to be the above result
I've only posted parts of the code but if it helps i can post the rest. I just need a little guidance if possible
Thanks
This is the full code
Dim numfiles As Integer
ReDim AllDetail(0 To 0)
numfiles = 0
lb1.Items.Clear()
Dim lynxin As New IO.DirectoryInfo(zMailbox)
lb1.Items.Clear()
For Each txtfi In lynxin.GetFiles("*.txt")
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
ReDim Preserve AllDetail(0 To numfiles)
AllDetail(numfiles).uPath = 'Needs to be populated
AllDetail(numfiles).uName = 'Needs to be populated
AllDetail(numfiles).uCode = 'Needs to be populated
AllDetail(numfiles).uOps = 'Needs to be populated
lb1.Items.Add(IO.Path.GetFileNameWithoutExtension(txtfi.Name))
numfiles = numfiles + 1
Next
End Sub
AllDetail(numfiles).uPath = Would be the actual file path
AllDetail(numfiles).uName = Would be the detail after “unitname=”
AllDetail(numfiles).uCode = Would be the detail after “unitcode=”
AllDetail(numfiles).uOps = Would be the detail after “operation=”
Within the text files that are being read there will be the following lines
Unitname=
Unitcode=
Operation=
Requirements=
Dateplanned=
For the purpose of this array I just need the unitname, unitcode & operation. Going forward I will need the dateplanned as when this is working I want to try and work out how to only display the information if the dateplanned matches the date from a datepicker. Hope that helps and any guidance or tips are gratefully received
If your file is not very big you could simply
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
For each line in allLines
Dim parts = line.Split("="c)
if parts.Length = 2 andalso parts(0) = "unitname" Then
AllDetails(numFiles).uName = parts(1)
Exit For
End If
Next
If you are absolutely sure of the format of your input file, you could also use Linq to remove the explict for each
Dim line = allLines.Where(Function(x) (x.StartsWith("unitname"))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
EDIT
Looking at the last details added to your question I think you could rewrite your code in this way, but still a critical piece of info is missing.
What kind of object is supposed to be stored in the array AllDetails?
I suppose you have a class named FileDetail as this
Public class FileDetail
Public Dim uName As String
Public Dim uCode As String
Public Dim uCode As String
End Class
....
numfiles = 0
lb1.Items.Clear()
Dim lynxin As New IO.DirectoryInfo(zMailbox)
' Get the FileInfo array here and dimension the array for the size required
Dim allfiles = lynxin.GetFiles("*.txt")
' The array should contains elements of a class that have the appropriate properties
Dim AllDetails(allfiles.Count) as FileDetail
lb1.Items.Clear()
For Each txtfi In allfiles)
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
AllDetails(numFiles) = new FileDetail()
AllDetails(numFiles).uPath = txtfi.FullName
Dim line = allLines.Where(Function(x) (x.StartsWith("unitname="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("unitcode="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("operation="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uOps = line.Split("="c)(1)
End If
lb1.Items.Add(IO.Path.GetFileNameWithoutExtension(txtfi.Name))
numfiles = numfiles + 1
Next
Keep in mind that this code could be really simplified if you start using a List(Of FileDetails)