private void Form1_Load(object sender, EventArgs e)
        {
            Text = "Otel Otomasyonu" + "-" + Tools.KullaniciAdSoyad().ToUpper();
            //menuStrip1.Items[3].Visible = false;
            if (PersonellerORM.AktifKullanici.YetkiID == 1)
            {
            }
            else if (PersonellerORM.AktifKullanici.YetkiID == 2)
            {
                kasaToolStripMenuItem.Visible             = false;
                kasaHareketTipiToolStripMenuItem1.Visible = false;
            }
            else
            {
                menuStrip1.Items[0].Visible = false;
                menuStrip1.Items[1].Visible = false;
                menuStrip1.Items[2].Visible = false;
                menuStrip1.Items[4].Visible = false;
                menuStrip1.Items[5].Visible = false;
                menuStrip1.Items[7].Visible = false;
            }
            çıkışToolStripMenuItem.Alignment = ToolStripItemAlignment.Right;
            çıkışToolStripMenuItem.BackColor = Color.Red;

            CloseAllMdiChildForms();
            if (musForm.IsDisposed)
            {
                musForm = new MusteriForm();
            }
            musForm.MdiParent   = this;
            musForm.WindowState = FormWindowState.Maximized;

            musForm.Show();
        }
        private void müşterilerToolStripMenuItem_Click(object sender, EventArgs e)
        {
            CloseAllMdiChildForms();
            if (musForm.IsDisposed)
            {
                musForm = new MusteriForm();
            }
            musForm.MdiParent   = this;
            musForm.WindowState = FormWindowState.Maximized;

            musForm.Show();
        }