SqlConnection conn = new SqlConnection(@" Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\proje\Student\Student\data\okul.mdf;Integrated Security=True;Connect Timeout=30;");
            conn.Open();
            SqlCommand cmd = new SqlCommand("Insert into ogrenci(adi) values ('" + TextBox1.Text + "')", conn);
            cmd.ExecuteNonQuery();
            TextBox1.Text = "";