[Ctrl]キーを押下しながらボタンクリック時の判定

private void Form1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.A && e.Control)
    {
        this.Text = "Ctrl + A";
    }
    else if (e.KeyCode == Keys.A)
    {
        this.Text = "A";
    }
    else
    {
        this.Text = "none";
    }
}

Private Sub Form1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) _
    Handles MyBase.KeyDown

    If e.KeyCode = Keys.A AndAlso e.Control Then
        Me.Text = "Ctrl + A"
    ElseIf e.KeyCode = Keys.A Then
        Me.Text = "A"
    Else
        Me.Text = "none"
    End If

End Sub

	Private Sub ButtonA_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonA.Click
		If My.Computer.Keyboard.CtrlKeyDown Then
			MsgBox("CTRL key down")
		Else
			MsgBox("CTRL key up")
		End If
	End Sub

    Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click 
        If (System.Windows.Forms.Control.ModifierKeys And Keys.Shift) = Keys.Shift Then
            MessageBox.Show("Shift キーを押しながら Button1 をクリックしやがったな")
        Else
            MessageBox.Show("Button1 をクリックしやがったな")
        End If
    End Sub