C# Uyarı Mesajı

 
  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; 
  using System.Data.OleDb; 
  using System.Globalization; 
  using System.Threading; 
   
  namespace AraçTakip 
  { 
      public partial class Form1 : Form 
      {         
          public Form1() 
          { 
              InitializeComponent(); 
          } 
   
          OleDbConnection con = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=data.accdb"); 
          OleDbDataAdapter da; 
   
          void listele() 
          {             
              con.Open(); 
              da = new OleDbDataAdapter("select * from liste", con); 
              DataTable tablo = new DataTable(); 
              da.Fill(tablo); 
              dataGridView1.DataSource = tablo; 
              con.Close(); 
          }        
   
          private void Form1_Load(object sender, EventArgs e) 
          { 
              listele(); 
          } 
   
          public void kontrol() 
          { 
              OleDbCommand komut = con.CreateCommand(); 
              con.Open(); 
              komut = new OleDbCommand("Select * From liste Where tarih='" + DateTime.Now + "'", con); 
              OleDbDataReader oku = komut.ExecuteReader(); 
              while (oku.Read()) 
              { 
                  MessageBox.Show("Vizesi Gelen Araçlar", "Deneme"); 
              } 
              con.Close(); 
   
          } 
   
          private void button1_Click(object sender, EventArgs e) 
          {             
              OleDbCommand cmd = con.CreateCommand(); 
              con.Open(); 
              cmd.CommandText = "Insert into liste(plaka,marca,model,tarih)Values(@plaka,@marca,@model,@tarih)"; 
              cmd.Connection = con; 
              cmd.Parameters.AddWithValue("@plaka", textBox1.Text); 
              cmd.Parameters.AddWithValue("@marca", textBox2.Text); 
              cmd.Parameters.AddWithValue("@model", textBox3.Text); 
              cmd.Parameters.AddWithValue("@tarih", dateTimePicker1.Value); 
              cmd.ExecuteNonQuery(); 
              MessageBox.Show("Kayıt Yapıldı", "Başırıyla Tamamlandı"); 
              con.Close(); 
              listele(); 
          } 
   
          private void button2_Click(object sender, EventArgs e) 
          { 
              OleDbCommand cmd = con.CreateCommand(); 
              con.Open(); 
              cmd.CommandText = "Delete From liste Where plaka=@plaka"; 
              cmd.Connection = con; 
              cmd.Parameters.AddWithValue("@plaka", dataGridView1.CurrentRow.Cells[0].Value);             
              cmd.ExecuteNonQuery(); 
              MessageBox.Show("Silme İşlemi Yapıldı", "Başırıyla Tamamlandı"); 
              con.Close(); 
              listele(); 
          } 
   
          private void button3_Click(object sender, EventArgs e) 
          { 
              OleDbCommand cmd = con.CreateCommand(); 
              con.Open(); 
              cmd.CommandText = "Update liste Set marca=@marca,model=@model,tarih=@tarih Where plaka=@plaka"; 
              cmd.Connection = con;             
              cmd.Parameters.AddWithValue("@marca", textBox2.Text); 
              cmd.Parameters.AddWithValue("@model", textBox3.Text); 
              cmd.Parameters.AddWithValue("@tarih", dateTimePicker1.Value); 
              cmd.Parameters.AddWithValue("@plaka", textBox1.Text); 
              cmd.ExecuteNonQuery(); 
              MessageBox.Show("Güncelleme Yapıldı", "Başırıyla Tamamlandı"); 
              con.Close(); 
              listele(); 
          } 
   
          private void dataGridView1_CellEnter(object sender, DataGridViewCellEventArgs e) 
          { 
              textBox1.Text = dataGridView1.CurrentRow.Cells[0].Value.ToString(); 
              textBox2.Text = dataGridView1.CurrentRow.Cells[1].Value.ToString(); 
              textBox3.Text = dataGridView1.CurrentRow.Cells[2].Value.ToString(); 
              dateTimePicker1.Value = Convert.ToDateTime(dataGridView1.CurrentRow.Cells[3].Value.ToString()); 
          }        
      } 
  }