You didn't provide your code.
I am writing sample code, You can achieve your requirement like this way:
txtalp.Text = "22"
Dim x As String = ""
For k As Integer = 1 To (Convert.ToInt32(textBox1.Text))
listBox2.Items.Add(k)
Next
For i As Integer = 0 To listBox2.Items.Count - 1
x += "-" + listBox2.Items(i)
Next
x = x.Remove(0, 1)
textBox1.Text = x