的WinForm的DataGridView只有一行，雖然數據源有兩個或更多的行

Question

我設置列表有2個元素到DataGridView的DataSource，但它總有一個行，行數屬性爲1.這太奇怪了

我下面的代碼有一些我必須解釋的實體類名。

HoaDon is Order 
ChiTietHoaDon is OrderDetail 
SanPham is Product 

代碼：

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

這是因爲你使用List<ChiTietHoaDon>爲您的datagridview的數據源，因此電網不顯示新項目，它不更改通知。

您應該改用BindingList<ChiTietHoaDon>。

但是，如果你想繼續使用List<ChiTietHoaDon>，更新您可以先設置dgrChiTiet.DataSource=null;的網格，然後dgrChiTiet.DataSource = allChiTiet;