Private Sub b_simpan_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles b_simpan.Click
        If K_bukuTextBox.Text = "" Then
            MsgBox("Data Tidak Lengkap", vbCritical, "Salah")
            K_bukuTextBox.Focus()
        ElseIf Judul_bukuTextBox.Text = "" Then
            MsgBox("Data Tidak Lengkap", vbCritical, "Salah")
            Judul_bukuTextBox.Focus()
        ElseIf KategoriTextBox.Text = "" Then
            MsgBox("Data Tidak Lengkap", vbCritical, "Salah")
            KategoriTextBox.Focus()
        ElseIf Jumlah_bukuTextBox.Text = "" Then
            MsgBox("Data Tidak Lengkap", vbCritical, "Salah")
            Jumlah_bukuTextBox.Focus()
        ElseIf SumberTextBox.Text = "" Then
            MsgBox("Data Tidak Lengkap", vbCritical, "Salah")
            SumberTextBox.Focus()
        Else : simpan()
        End If
        tampildata()
        kosongkan()
    End Sub

    Private Sub b_ubah_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles b_ubah.Click
        ubah()
        tampildata()
        kosongkan()
    End Sub

    Private Sub b_hapus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles b_hapus.Click
        hapus()
        tampildata()
        kosongkan()
    End Sub

    Private Sub b_keluar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
        Close()
    End Sub

    Private Sub b_databaru_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles b_databaru.Click
        kosongkan()
    End Sub