[英]WinForm DataGridView have only one row although DataSource have two or more rows
I set a List have 2 elements to the dataGridView's DataSource, but it's always have one row, the RowCount property is 1. This is so strange 我将一个List设置为dataGridView的DataSource包含2个元素,但它始终只有一行,RowCount属性为1。这很奇怪
My code below have some Entity class name which I must explain. 我下面的代码有一些实体类名称,我必须解释。
HoaDon is Order
ChiTietHoaDon is OrderDetail
SanPham is Product
Code: 码:
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";
}
}
}
}
This is because you are using List<ChiTietHoaDon>
as data source of your datagridview and it doesn't notify changes so the grid doesn't show new items. 这是因为您将
List<ChiTietHoaDon>
用作datagridview的数据源,并且它不会通知更改,因此网格不会显示新项目。
You should use BindingList<ChiTietHoaDon>
instead. 您应该改用
BindingList<ChiTietHoaDon>
。
But if you want to continue using List<ChiTietHoaDon>
, to update the grid you can first set dgrChiTiet.DataSource=null;
但是,如果要继续使用
List<ChiTietHoaDon>
来更List<ChiTietHoaDon>
格,则可以首先设置dgrChiTiet.DataSource=null;
and then dgrChiTiet.DataSource = allChiTiet;
然后
dgrChiTiet.DataSource = allChiTiet;
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