Get values from listarray VB NET 2008

[doomfrawen]

Hi everyone, I have to make a program that reads a txt file after reading it, show it in a richtext box and in another tab make the average of the grades the input received sort it by the student id and then in the same rtb sort it by the average of their grades, and finally save it on a new text file.

The text file input is something like this

12 3 10.0 6.9 7.3
19 2 6.7 9.3
10 3 4.5 9.3 4.5

and the output should look like this

sorted by student ID
10 6.1 4.5 9.3 4.5
12 8.1 10.0 6.9 7.3
19 5.3 6.7 9.3

sorted by grade average
12 8.1 10.0 6.9 7.3
10 6.1 4.5 9.3 4.5
19 5.3 6.7 9.3

As you noticed in the input the first number is the student ID, the second number is the number of tests made by the student, and the other 3 numbers are grades, in the output the first number is the student ID, the second number is the average of the tests, and the other 3 numbers are grades, but my problem is that I can't get the values from the list that I 've created, here is the code:

      Imports System.IO

      Public Class Form1

          Private Sub AbrirToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles AbrirToolStripMenuItem.Click

              ' Try

              Dim txtString As String()

              txtString = System.IO.File.ReadAllLines("C:\read.txt")

              ' Catch ioexception As IOException

              'MsgBox("File Not Found")

              Dim studentList As New System.Collections.Generic.Dictionary(Of Integer, Decimal())
 
              For Each line As String In txtString
 
                  If (String.IsNullOrEmpty(line)) Then
 
                      Continue For

                  End If

                  Dim data As String() = line.Split(" ")
 
                  Dim studentId As Integer = Convert.ToInt32(data(0))

                  Dim gradeList As New List(Of Decimal)
       

                  For i1 As Integer = 1 To data.Length - 1

                      gradeList.Add(Convert.ToDecimal(data(i1)))
       

                  Next
       
                  studentList.Add(studentId, gradeList.ToArray())      

              Next

              'At this point I have it all in memory :)
       

             'this code should retrieve me the values but it doesn't

             'the error says that the key has not been found on the dictionary
       

              Dim value1 As Object

              value1 = studentList(1)

              RichTextBox1.Text = value1
 
              'End Try
  
          End Sub

thanks in advance I really appreciate all your help

[chkmos]

I hope you don't mind if I rewrite the code for definition interpretation.

In the program, you should use the following approach in writing this program.
1. Load a file definition (which you have done)
2. Declare a Student Class definition
3. Define the sorting ability of the class (IComparable)
4. Read the definition into student class list

According to the guidelines, i have written the class definition as followed.
Class Definition

Public Class Student : Implements IComparable(Of Student)
        Public StudentID As Integer
        Public ReadOnly Property TestCount() As Integer
            Get
                Return Grades.Count
            End Get
        End Property
        Public Grades As New List(Of Decimal)
        Public ReadOnly Property AverageGrade() As Decimal
            Get
                Return Math.Round(Grades.Average(), 1)
            End Get
        End Property

        Public Sub New(ByVal def As String)
            Dim tmp As String() = def.Split(" ")
            If tmp.Length = 0 Then Throw New ApplicationException("The student definition cannot be empty.")

            StudentID = Integer.Parse(tmp(0))
            Dim count As Integer = Integer.Parse(tmp(1)) 'tmp(1) is the test count, use it for validation only
            For n = 2 To tmp.Length - 1
                Grades.Add(Decimal.Parse(tmp(n)))
            Next

            If Not count = Grades.Count Then Throw New ApplicationException("The number of test and grades does not match")
        End Sub

        Public Function GetResult() As String
            Dim tmp1 As String = StudentID & " " & AverageGrade.ToString()
            Dim tmp2 As String = ""

            For n As Integer = 0 To Grades.Count - 1
                If n = 0 Then
                    tmp2 = Grades(n)
                Else
                    tmp2 &= " " & Grades(n)
                End If
            Next

            Return tmp1 & " " & tmp2
        End Function

        Public Function CompareTo(ByVal other As Student) As Integer Implements System.IComparable(Of Student).CompareTo
            Return StudentID.CompareTo(other.StudentID)
        End Function
    End Class

    Public Class StudentGradeComparer : Implements IComparer(Of Student)
        Public Function Compare(ByVal x As Student, ByVal y As Student) As Integer Implements System.Collections.Generic.IComparer(Of Student).Compare
            Return x.AverageGrade.CompareTo(y.AverageGrade)
        End Function
    End Class

Also, to use this class, you should create 3 textboxes and 3 buttons.

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim students As New List(Of Student)

        'Read input lines
        For Each line In TextBox1.Lines
            students.Add(New Student(line))
        Next

        'Sort By Student ID
        students.Sort()
        TextBox2.Text = ""
        For n As Integer = 0 To students.Count - 1
            TextBox2.Text &= students(n).GetResult() & vbCrLf
        Next

        'Sort By Average Grade
        students.Sort(New StudentGradeComparer())
        TextBox3.Text = ""
        For n As Integer = students.Count - 1 To 0 Step -1
            TextBox3.Text &= students(n).GetResult() & vbCrLf
        Next
    End Sub

By the way, you have got a mistake in the example (You divided the total score by 3, which should be 2 !)
19 5.3 6.7 9.3 should be 19 8 6.7 9.3

This program use Visual Basic 2008 functionality, therefore, it should be opened by Visual Basic 2008.

I have attached the code for you for your reference. Hope that i can help you ^.^.