Get prime number in Visual Basic

I need to write a Windows Form application in visual studio that contain a text box and it shows the prime number from 1 to 100 and those number are separated by "|"

For example it looks like this 1 | 2 | 3 | 5 ...

 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    IsPrime()

End Sub
Private Sub IsPrime()
    Dim checkPrime = 1, i, primeNumber As Integer
    For primeNumber = 1 To 100
        For i = 2 To primeNumber - 1
            If primeNumber Mod i = 0 Then
                checkPrime = 0 'Not prime number'
                Exit For
            Else
                checkPrime = 1 'Is prime number
            End If
        Next
        If checkPrime = 1 Then
            Me.Txt_PrimeNumber.Text = primeNumber.ToString + "| "

        End If
    Next

End Sub

But now when i run it, it only display

97|