Read from text file, store data into corresponding structure every 6 element, and then form an array - vb.net

Question

The text file contains the following: inside the [], anything inside () was not in the text file, just for clarification
[1(ID)
Jimmy(First name)
Paul (Last name)
78 (marks1)
80 (marks2)
92 (marks3)
2
Ben
James
67
82
73
]
I created a structure that holds student details including their name, id, marks in each subject.
Private Structure StudInfo
Public FName As String
Public LName As String
Public StudentId As Integer
Public ScMark As Integer
Public EnMark As Integer
Public MaMark As Integer
The program needs to read the first six elements in a row, storing each element into the corresponding structure type, then let it become the first element of an array"students()", and then next six elements, let it become the second element of that array. I have no idea how to use loops to do that.
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
'create an array that hold student details
Dim Students() As StudInfo
' read from text file
Dim FileNum As Integer = FreeFile()
Dim TempS As String = ""
Dim TempL As String
FileOpen(FileNum, "some.text", OpenMode.Input)
Do Until EOF(FileNum)
TempL = LineInput(FileNum)
TempS = TempL + vbCrLf
Loop
End Sub
Thank you.

Answer 1

You have to use a BinaryReader (which takes a IO.Stream as it's constructor), then you can read the data type you want, into the variable you want.
The problem you will have is the data will not be searchable (ie. you cannot read the 30th record, unless you physically read the first 29, because the strings are of variable length, and therefore the record is variable length), this also applies to modifying a record (you cant make it bigger, because it will overwrite the next record).
The answer is to work with fixed length records, or field offsets or fixed length strings. Then you will have a records of predictable size, and you can determine the amount of records by dividing the file length by the record size.
Hope this helps.

Answer 2

You could try something like this:
Public Class Form1
Private Students As New List(Of StudInfo)
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Students.Clear()
Dim fileName = "c:\some folder\directory\someFile.txt"
Using sr As New System.IO.StreamReader(fileName)
Dim value As Integer
Dim strValue As String
While Not sr.EndOfStream
Try
Dim student As New StudInfo
strValue = sr.ReadLine().Trim("[]")
If Integer.TryParse(strValue, value) Then
student.StudentId = value
Else
MessageBox.Show("Error Converting StudentID to Integer")
Exit Sub
End If
student.FName = sr.ReadLine().Trim("[]")
student.LName = sr.ReadLine().Trim("[]")
strValue = sr.ReadLine().Trim("[]")
If Integer.TryParse(strValue, value) Then
student.ScMark = value
Else
MessageBox.Show("Error Converting ScMark to Integer")
Exit Sub
End If
strValue = sr.ReadLine().Trim("[]")
If Integer.TryParse(strValue, value) Then
student.EnMark = value
Else
MessageBox.Show("Error Converting EnMark to Integer")
Exit Sub
End If
strValue = sr.ReadLine().Trim("[]")
If Integer.TryParse(strValue, value) Then
student.MaMark = value
Else
MessageBox.Show("Error Converting MaMark to Integer")
Exit Sub
End If
Students.Add(student)
Catch ex As Exception
MessageBox.Show("Error reading file. All records may not have been created.")
End Try
End While
MessageBox.Show("Done!")
End Using
End Sub
Private Class StudInfo
Public FName As String
Public LName As String
Public StudentId As Integer
Public ScMark As Integer
Public EnMark As Integer
Public MaMark As Integer
End Class
End Class

Answer 3

It depends a bit on the exact format of your text file.
If the file only contains the data for the two students (no brackets or blank lines), then all you need to do is to open the file and read 6 lines, add the data to your structure. and read the next 6 lines. If you have an undetermined number of students in the text file, then you would be better using a List. Other wise you're goiing to have to use extra processing time to Redim the array each time you want to add a student and keep track of the array size an all sorts of messing around.
However. Lets go with the most straightforward answer and assume your data has no brackets or blank lines and that there are only two students.
This code should work just fine. If you have a different definite number of students, then you will need to change the size of the Students array.
I'm also assuming that the data is correctly formatted and there are no non-numeric characters are in the lines where there shouldn't be.
Private Sub ReadStudentInfo()
'create an array that hold student details
Dim Students(2) As StudInfo
Dim index As Integer = 0
' read from text file
Dim datafile As New StreamReader("some.text")
Do Until datafile.EndOfStream
Dim tempStudent As StudInfo
With tempStudent
Integer.TryParse(datafile.ReadLine, .StudentId)
.FName = datafile.ReadLine
.LName = datafile.ReadLine
Integer.TryParse(datafile.ReadLine, .ScMark)
Integer.TryParse(datafile.ReadLine, .EnMark)
Integer.TryParse(datafile.ReadLine, .MaMark)
End With
Students(index) = tempStudent
index = index + 1
Loop
End Sub
If your text file does contain blank lines, just insert
datafile.ReadLine()
between each line of data - like this
Integer.TryParse(datafile.ReadLine, .ScMark)
datafile.ReadLine()
Integer.TryParse(datafile.ReadLine, .EnMark)
If you have the brackets in your text file, then you'll need to add extra code to remove them.