private void BtnSearch_Click(object sender, EventArgs e)
        {
            ep.Clear();

            if (txtSearchUserName.Text.Trim().Length == 0)
            {
                ep.SetError(txtSearchUserName, "Kullacı adı boş bırakılamaz!");
                txtSearchUserName.Focus();
                return;
            }
            if (txtSearchPassword.Text.Trim().Length == 0)
            {
                ep.SetError(txtSearchPassword, "Şifre boş bırakılamaz!");
                txtSearchPassword.Focus();
                return;
            }


            var check   = UsersHelper.Login(txtSearchUserName.Text, txtSearchPassword.Text).Item1;
            var staffID = UsersHelper.Login(txtSearchUserName.Text, txtSearchPassword.Text).Item2;

            if (check)
            {
                var userPrivileges = UserPrivilegesHelper.GetByStaffID(staffID);

                chkConfiguration.Checked = Convert.ToBoolean(userPrivileges.Configuration);
                chkStaff.Checked         = Convert.ToBoolean(userPrivileges.Staff);
                chkStudent.Checked       = Convert.ToBoolean(userPrivileges.Student);
                chkBook.Checked          = Convert.ToBoolean(userPrivileges.Book);
                chkIssueBook.Checked     = Convert.ToBoolean(userPrivileges.IssueBook);
                chkReturnBook.Checked    = Convert.ToBoolean(userPrivileges.ReturnBook);
                chkReport.Checked        = Convert.ToBoolean(userPrivileges.Report);
                chkGSM.Checked           = Convert.ToBoolean(userPrivileges.Gsm);
                chkEmail.Checked         = Convert.ToBoolean(userPrivileges.Email);

                var staff = StaffsHelper.GetById(staffID);
                txtUpdateUser.Text = staff.Name;
                txtContactNo.Text  = staff.ContactNo;

                var designation = DesignationsHelper.GetById(staff.DesignationID);
                txtDesignation.Text = designation.Name;

                btnUpdate.Enabled         = true;
                txtSearchUserName.Enabled = false;
                txtSearchPassword.Enabled = false;
                btnSearch.Enabled         = false;
            }
            else
            {
                MessageBox.Show("Kullanıcı Adı ve Şifre Eşleşmiyor.", "Library Management System", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
        }
        private void btnEdit_Click(object sender, EventArgs e)
        {
            if (dgvStaffList.Rows.Count > 0)
            {
                if (dgvStaffList.SelectedRows.Count == 1)
                {
                    int selectIndex = dgvStaffList.CurrentRow.Index;
                    var staffID     = dgvStaffList.Rows[selectIndex].Cells[0].Value;

                    var s = StaffsHelper.GetById(Convert.ToInt32(staffID));
                    var d = DesignationsHelper.GetById(s.DesignationID);

                    cmbDesignation.SelectedItem = d.Name;
                    txtName.Text            = s.Name;
                    txtTcNo.Text            = s.TCNO;
                    cmbGender.SelectedIndex = s.Gender;
                    txtAddress.Text         = s.Address;
                    txtContactNo.Text       = s.ContactNo;

                    EnableComponent();
                }
            }
        }