private void insert_Click(object sender, EventArgs e)
        {
            int?SL = null;

            universityData.Teacher_Insert(textBox2.Text, textBox3.Text, ref SL);
            textBox1.Text = SL.ToString();
            universityData.SubmitChanges();

            ///aita te akta jhamela ache ata insert korar por just akta value update hoy ak tar ashi hoy na
            //Table<Teacher> teachers = universityData.Teachers;
            //dataGridView1.DataSource = teachers;

            ShowtheTables();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            UniversityDataDataContext universityData = new UniversityDataDataContext();//conn established

            if (textBox1.ReadOnly == false)
            {
                Student student = new Student();
                student.Id     = Convert.ToInt32(textBox1.Text); // or, student.Id = int.Parse(textBox1.Text);
                student.S_Name = textBox2.Text;
                student.Reg    = textBox3.Text;
                universityData.Students.InsertOnSubmit(student); //inserting on student table as a row
                universityData.SubmitChanges();                  //comminting the changes
                MessageBox.Show("Record inserted into the Student Table");
            }
            else
            {
                Student student = universityData.Students.SingleOrDefault(E => E.Id == int.Parse(textBox1.Text));
                student.Id     = int.Parse(textBox1.Text);
                student.S_Name = textBox2.Text;
                student.Reg    = textBox3.Text;
                universityData.SubmitChanges();//comminting the changes
                MessageBox.Show("Record updated into the Student Table");
            }
        }
 private void button3_Click(object sender, EventArgs e)
 {
     if (dataGridView1.SelectedRows.Count > 0)
     {
         if (MessageBox.Show("Are you sure of deleting the selected row?", "Confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
         {
             int     rowsel  = Convert.ToInt32(dataGridView1.SelectedRows[0].Cells[0].Value);
             Student student = universityData.Students.SingleOrDefault(E => E.Id == rowsel);
             universityData.Students.DeleteOnSubmit(student);
             universityData.SubmitChanges();//comminting the changes
             LoadTable();
         }
     }
     else
     {
         MessageBox.Show("Please Select the entire Row ");
     }
 }