WinForm DataGridView只有一行，盡管DataSource有兩行或更多行

Question

我將一個List設置為dataGridView的DataSource包含2個元素，但它始終只有一行，RowCount屬性為1。這很奇怪

我下面的代碼有一些實體類名稱，我必須解釋。

HoaDon is Order
ChiTietHoaDon is OrderDetail
SanPham is Product

碼：

using GymFitnessOlympic.Controller;
using GymFitnessOlympic.Models;
using GymFitnessOlympic.Models.Util;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace GymFitnessOlympic.View.ActForm
{
    public partial class FrmBanHang2 : Form
    {
        List<SanPham> allSanPham;
        List<ChiTietHoaDon> allChiTiet = new List<ChiTietHoaDon>();
        HoaDon hoaDon = new HoaDon();

        public FrmBanHang2()
        {
            InitializeComponent();
            int phongID = Login.GetPhongHienTai().MaPhongTap;
            allSanPham = SanPhamController.GetList(phongID);
            dgrChiTiet.AutoGenerateColumns = false;
            dgrChiTiet.AutoGenerateColumns = false;
            loadListSanPham(allSanPham);
        }

        void loadListSanPham(List<SanPham> li)
        {

            lbSanPham.DataSource = li;
        }

        void updateTable()
        {
            dgrChiTiet.DataSource = allChiTiet;
            int n = dgrChiTiet.RowCount;
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            if (spnQuantity.Value <= 0)
            {
                dxErrorProvider1.SetError(spnQuantity, "Quantity must be greater than 0");
                spnQuantity.Focus();
                return;
            }
            int gia;
            if (!int.TryParse(txtPrice.Text, out gia) || (gia % 500 != 0) || gia <= 0)
            {
                txtPrice.Focus();
                dxErrorProvider1.SetError(txtPrice, "Invalid Price");
                return;
            }
            if (lbSanPham.SelectedItem != null)
            {
                var sp = (SanPham)lbSanPham.SelectedItem;
                int soLuong = int.Parse(spnQuantity.Text);
                ChiTietHoaDon c = new ChiTietHoaDon()
                {
                    Gia = gia,
                    MaSanPham = sp.MaSanPham,
                    SoLuong = soLuong,
                    SanPham = sp

                };
                var old = allChiTiet.FirstOrDefault(c1 => c1.MaSanPham == c.MaSanPham);
                if (old != null)
                {
                    old.SoLuong += c.SoLuong;
                }
                else
                {
                    allChiTiet.Add(c);
                }
            }
            updateTable();
        }

        private void lbSanPham_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (lbSanPham.SelectedItem != null)
            {
                var sp = (SanPham)lbSanPham.SelectedItem;
                txtTenSanPham.Text
                     = sp.TenSanPham;
                txtPrice.Text = sp.Gia.ToString();
                spnQuantity.Text = "1";
            }
        }
    }
}

Answer 1

這是因為您將List<ChiTietHoaDon>用作datagridview的數據源，並且它不會通知更改，因此網格不會顯示新項目。

您應該改用BindingList<ChiTietHoaDon> 。

但是，如果要繼續使用List<ChiTietHoaDon>來更List<ChiTietHoaDon>格，則可以首先設置dgrChiTiet.DataSource=null; 然后dgrChiTiet.DataSource = allChiTiet;