i was given a practice code and when i executed the code everything went well. now when i deleted the CStr from a label it was assigned to, i noticed that the program did not do anything different, everything went well as it should have, unless i didnt check somewhere i was supposed to?

for example in my code.....
Code:
Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ListBox1.Items.Add("COMP 2110")
        ListBox1.Items.Add("COMP 2120")
        ListBox1.Items.Add("COMP 2300")
        ListBox1.Items.Add("COMP 2315")
        ListBox1.Items.Add("COMP 2400")
        ListBox1.Items.Add("COMP 2501")
        ListBox1.Items.Add("GEIC 1000")
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        
        Dim num As Integer
        Dim Count As Integer
        Dim file_courses As IO.StreamWriter = IO.File.CreateText("Courses.dat")
        

        Label1.Text = CStr(ListBox1.Items.Count)//when i deleted this CStr nothing different happened? what was supposed to happen?

        For num = 0 To (ListBox1.Items.Count)
            file_courses.Write(ListBox1.Items(Count))

        Next

        file_courses.Close()
    End Sub
End Class
so again i ask why do we need or what is the importance of CStr?