Public Class Form1

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
TextBox_log.Text = TextBox_log.Text & "1111" & Environment.NewLine
End Sub

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
TextBox_log.Text = TextBox_log.Text & "2222" & Environment.NewLine
End Sub

Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
TextBox_log.Text = TextBox_log.Text & "333" & Environment.NewLine
End Sub
End Class