Vb.Net textbox’a girilen sayıya kadar olan sayıları listbox’a dik üçgen olarak ekleme

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim i, j As Integer 

Dim gec As String

gec = ""

ListBox1.Items.Clear()

For i = 1 To Val(TextBox1.Text)

For j = 1 To i

gec = gec & " " & j

Next j

ListBox1.Items.Add(gec)

gec = ""

Next i

gec = ""

ListBox2.Items.Clear()

For i = Val(TextBox1.Text) To 1 Step -1

For j = i To 1 Step -1

gec = gec & " " & j

Next j

ListBox2.Items.Add(gec)

gec = ""

Next i

End Sub

End Class