Notes

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace _CarsDBApp
{
public partial class FrmCountry : Form
{
public FrmCountry()
{
InitializeComponent();
}

private void btnInsert_Click(object sender, EventArgs e)
{
using (CarDBEntities db = new CarDBEntities())
{
db.Countries.Add(new Country { CountryName = textBox1.Text });
db.SaveChanges();
}
ListCountry();
}

private void FrmCountry_Load(object sender, EventArgs e)
{
ListCountry();
}
public void ListCountry()
{
using (CarDBEntities db = new CarDBEntities())
{
var country = (from b in db.Countries
select new
{
CountryId = b.CountryId,
CountryName = b.CountryName
}).ToList();
dataGridView1.DataSource = country;
}
}
int id;
private void btnDelete_Click(object sender, EventArgs e)
{

if (id != 0)
{
using (CarDBEntities db = new CarDBEntities())
{
Country county = db.Countries.Where(b => b.CountryId == id).FirstOrDefault();
DialogResult r = MessageBox.Show(string.Format("{0} adlı markayı silmek istediğinizden emin misiniz?", county.CountryName), "Silme İşlemi", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2);
switch (r)
{
case DialogResult.Yes:
db.Countries.Remove(county);
db.SaveChanges();
break;
}

}

}
ListCountry();
}




private void dataGridView1_CellEnter(object sender, DataGridViewCellEventArgs e)
{
id = Convert.ToInt32(dataGridView1.Rows[e.RowIndex].Cells["CountryId"].Value);
textBox1.Text = dataGridView1.Rows[e.RowIndex].Cells["CountryName"].Value.ToString();
}

private void btnUpdate_Click(object sender, EventArgs e)
{
if (id != 0)
{

using (CarDBEntities db = new CarDBEntities())
{
Country country = db.Countries.Where(b => b.CountryId == id).FirstOrDefault();
if (country != null)
{
country.CountryName = textBox1.Text;
db.SaveChanges();
}
}
}
ListCountry();

}
}
}