C# form ile veritabanı bağlantısı nasıl kurulur?

Toolbox’dan eklenecekler: 3 Label, 3 Button, 3 Textbox, 1 DataGridView.

Referansa Eklenecek:

using System.Data.SqlClient;

Form1 public partial class’ın altına yazılacak:

SqlConnection baglanti = new SqlConnection("Data Source=.;Initial Catalog=okul;
Integrated Security=True");
void listele()
        {
            if (baglanti.State==ConnectionState.Closed)
            {
                baglanti.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = baglanti;
                cmd.CommandText = "SELECT * FROM ogrenci";
                SqlDataAdapter adaptor = new SqlDataAdapter(cmd);
                DataSet ds = new DataSet();
                adaptor.Fill(ds, "ogrenci");
                dataGridView1.DataSource = ds.Tables["ogrenci"];
                dataGridView1.Columns[0].Visible = false;
                baglanti.Close();
            }
        }
void temizle()
        {
            textBox1.Clear();
            textBox2.Clear();
            textBox3.Clear();
        }

Form1_Load:

listele();

Button1_Click:

if (baglanti.State==ConnectionState.Closed)
            {
                baglanti.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = baglanti;
                cmd.CommandText = "INSERT INTO ogrenci(numara, ad, soyad) 
VALUES('" + int.Parse(textBox1.Text) + "', '" + textBox2.Text + "', '" + textBox3.Text + "')";
                cmd.ExecuteNonQuery();
                cmd.Dispose();
                baglanti.Close();
                temizle();
                listele();
                MessageBox.Show("Kaydedildi!");
            }

Button2_Click:

if (baglanti.State==ConnectionState.Closed)
            {
                baglanti.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = baglanti;
                cmd.CommandText = "UPDATE ogrenci SET numara='" + int.Parse(textBox1.Text) + "',
 ad='" + textBox2.Text + "', soyad='" + textBox3.Text + "' WHERE sirano='" 
+ dataGridView1.CurrentRow.Cells[0].Value + "'";
                cmd.ExecuteNonQuery();
                cmd.Dispose();
                baglanti.Close();
                temizle();
                listele();
                MessageBox.Show("Güncellendi!");
            }            

DataGridView1_CellClick:

textBox1.Text = dataGridView1.CurrentRow.Cells[1].Value.ToString();
textBox2.Text = dataGridView1.CurrentRow.Cells[2].Value.ToString();
textBox3.Text = dataGridView1.CurrentRow.Cells[3].Value.ToString();

Button3_Click:

            if (baglanti.State==ConnectionState.Closed)
            {
                baglanti.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = baglanti;
                cmd.CommandText = "DELETE FROM ogrenci WHERE sirano='" + 
dataGridView1.CurrentRow.Cells[0].Value + "'";
                cmd.ExecuteNonQuery();
                cmd.Dispose();
                baglanti.Close();
                temizle();
                listele();
                MessageBox.Show("Silindi!");
            }     

Çıktısı:

Bu alana reklam verebilirsiniz!