How to assign a price to a string in a list box

Question

Doing a college tuition calculator and have a list box with 3 colleges already loaded I have a combo box with the credit hours loaded I have a button to calculate and a label to display the results. I am stuck on how to assign the 3 colleges in the list box a price per credit hour so that I can calculate after choosing a college and how many credit hours I want to get a price of the tuition. I am guessing I need to assign a price to each index in the list box but do not know how to set that up. Any advice would be appreciated.

Answer 1

Hi @Matthew Turcotte ,
You can store Key-Value pair in listbox.
Check the following example.

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load  
        ComboBox1.Items.Add(100)  
        ComboBox1.Items.Add(150)  
        ComboBox1.Items.Add(200)  
  
        Dim dic As Dictionary(Of String, Double) = New Dictionary(Of String, Double)()  
        dic.Add("College A", 4) '4 per credit hour'  
        dic.Add("College B", 4.5)  
        dic.Add("College C", 5)  
        ListBox1.DataSource = New BindingSource(dic, Nothing)  
        ListBox1.DisplayMember = "Key"  
        ListBox1.ValueMember = "Value"  
    End Sub  
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click  
        If ComboBox1.SelectedItem IsNot Nothing Then  
            Label1.Text = CDbl(ListBox1.SelectedValue) * CDbl(ComboBox1.SelectedItem)  
        End If  
    End Sub  

Result of my test.

Hope it could be helpful.

Best Regards,
Xingyu Zhao
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Answer 2

Here is an example that calculates without a button.

Full source

College class

Public Class College  
    Public Property Id() As Integer  
    Public Property Name() As String  
    Public Property Credit() As Double  
  
    Public Overrides Function ToString() As String  
        Return Name  
    End Function  
End Class  

Class for mocking up schools

Public Class Mocked  
    ''' <summary>  
    ''' Should come from a database or file  
    ''' </summary>  
    ''' <returns></returns>  
    Public Shared Function Colleges() As List(Of College)  
        Return New List(Of College) From {  
                New College() With {.Id = 1, .Name = "University Of Phoenix", .Credit = 10.5},  
                New College() With {.Id = 2, .Name = "Bryn Mawr College", .Credit = 20.5},  
                New College() With {.Id = 3, .Name = "Grinnell College", .Credit = 30.5},  
                New College() With {.Id = 4, .Name = "Capella University", .Credit = 40.5},  
                New College() With {.Id = 5, .Name = "Strayer University", .Credit = 60.5}  
            }  
    End Function  
End Class  

Form code

Public Class Form1  
    Private ReadOnly _collegeBindingSource As New BindingSource  
    Private ReadOnly _hoursBindingSource As New BindingSource  
    Private Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown  
        _collegeBindingSource.DataSource = Mocked.Colleges  
        SchoolListBox.DataSource = _collegeBindingSource  
  
        AddHandler _collegeBindingSource.PositionChanged, AddressOf _  
            BindingSources_PositionChanged  
  
        AddHandler _hoursBindingSource.PositionChanged, AddressOf _  
            BindingSources_PositionChanged  
  
        _hoursBindingSource.DataSource = Enumerable.  
            Range(100, 10).  
            Select(Function(item) (item * 2).ToString()).  
            ToList()  
  
        HoursComboBox.DataSource = _hoursBindingSource  
  
    End Sub  
  
    Private Sub BindingSources_PositionChanged(sender As Object, e As EventArgs)  
        Dim currentCollege = CType(_collegeBindingSource.Current, College)  
        CostLabel.Text =  
            $"Cost: {(currentCollege.Credit * CDbl(_hoursBindingSource.Current)).ToString("C")}"  
    End Sub  
End Class