Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.TextBox1.Multiline = True
End Sub
Sub do_that()
Dim o1, o2 As String
If CheckBox1.Checked = True Then o1 = vbNewLine Else o1 = ""
If CheckBox2.Checked = True Then o2 = vbNewLine Else o2 = ""
TextBox1.Text = ComboBox1.Text & o1 & ComboBox2.Text & o2
End Sub
Private Sub ComboBox2_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox2.SelectedIndexChanged
do_that()
End Sub
Private Sub CheckBox1_CheckedChanged(sender As Object, e As EventArgs) Handles CheckBox1.CheckedChanged
do_that()
End Sub
Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
do_that()
End Sub
Private Sub CheckBox2_CheckedChanged(sender As Object, e As EventArgs) Handles CheckBox2.CheckedChanged
do_that()
End Sub
End Class