Multiple CheckBoxes and TextBoxes VB.NET

Okay I have Check Boxes set to display code in Text Boxes with one check box checked. Now I am looking on how to check multiple check boxes and have that code displayed to the check box.

What I want is to have "SelectBox" and "UpBox" both checked to display in TextBox1 "0000FFEE", in TextBox2 "0010FFEE", in TextBox3 "00000011", and finally in TextBox4 "00100011".

Example code:

Private Sub SelectBox_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SelectBox.CheckedChanged
    If SelectBox.Checked = True Then
        TextBox1.Text = "0000FFFE"
        TextBox2.Text = "0010FFFE"
        TextBox3.Text = "00000001"
        TextBox4.Text = "00100001"
    Else
        TextBox1.Text = "0000FFFF"
        TextBox2.Text = "0010FFFF"
        TextBox3.Text = "00000000"
        TextBox4.Text = "00100000"

        End If
End Sub

Private Sub UpBox_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles UpBox.CheckedChanged
    If UpBox.Checked = True Then
        TextBox1.Text = "0000FFEF"
        TextBox2.Text = "0010FFEF"
        TextBox3.Text = "00000010"
        TextBox4.Text = "00100010"
    Else
        TextBox1.Text = "0000FFFF"
        TextBox2.Text = "0010FFFF"
        TextBox3.Text = "00000000"
        TextBox4.Text = "00100000"
    End If
End Sub