Public Class Form1
    Dim boobold As Boolean = False
    Dim booitalic As Boolean = False
    Dim boounderline As Boolean = False
    Private Sub chkBold_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkBold.CheckedChanged
        Dim boobold As Boolean = False
        If chkBold.CheckState = CheckState.Checked Then
            boobold = True
        Else
            boobold = False
        End If
    End Sub

    Private Sub chkItalic_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkItalic.CheckedChanged
        Dim booitalic As Boolean = False
        If chkItalic.CheckState = CheckState.Checked Then
            booitalic = True
        Else
            booitalic = False
        End If

    End Sub

    Private Sub chkUnderline_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkUnderline.CheckedChanged
        Dim boounderline As Boolean = False
        If chkUnderline.CheckState = CheckState.Checked Then
            boounderline = True
        Else
            booitalic = False
        End If
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub ruleall()
        If chkBold.CheckState = CheckState.Checked Then
            chkUnderline.CheckState = CheckState.Unchecked
            chkItalic.CheckState = CheckState.Unchecked
            txtdisplay.Font = New System.Drawing.Font(txtdisplay.Font, FontStyle.Bold)

        ElseIf chkItalic.CheckState = CheckState.Checked Then
            chkBold.CheckState = CheckState.Unchecked
            chkUnderline.CheckState = CheckState.Unchecked
            txtdisplay.Font = New System.Drawing.Font(txtdisplay.Font, FontStyle.Italic)

        ElseIf chkUnderline.CheckState = CheckState.Checked Then
            chkBold.CheckState = CheckState.Unchecked
            chkItalic.CheckState = CheckState.Unchecked
            txtdisplay.Font = New System.Drawing.Font(txtdisplay.Font, FontStyle.Underline)
            ' Else
            '     chkBold.CheckState = CheckState.Unchecked
            '    chkItalic.CheckState = CheckState.Unchecked
            '    txtdisplay.Font = New System.Drawing.Font(txtdisplay.Font, FontStyle.Regular)
        End If
    End Sub
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
        'Etc
    End Sub