insert-update in datagridview

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C#

dear all ,

i have small table student(id,name,last_name,address) and small screeen with datagridview iam trying to make insert and update
i want to add record in datagrid and then user enter data in that record
this my code , i do not know if it's possible or not

private void button1_Click(object sender, EventArgs e)
      {


              DataRow dr = dt.NewRow();
              dr["student_id"] = Convert.ToInt32(textBox1.Text);
              dr["student_name"] = textBox2.Text;
              dr["student_last_name"] = textBox3.Text;
              dr["address"] = textBox4.Text;
              dt.Rows.Add(dr);
              obj.addstudent(Convert.ToInt32(dr["student_id"].ToString()), dr["student_name"].ToString(), dr["student_last_name"].ToString(), dr["address"].ToString());
              dataGridView1.DataSource = dt;
      }

other thing update i want event firing after all cells in the same row updated not firing the event for each cell separetly like what happen in asp (rowupdating) this is my code :

int x, y;
       private void dataGridView1_CellBeginEdit(object sender, DataGridViewCellCancelEventArgs e)
       {
           x = dataGridView1.CurrentCellAddress.X;
           y = dataGridView1.CurrentCellAddress.Y;

       }

       private void dataGridView1_CancelRowEdit(object sender, QuestionEventArgs e)
       {
           x = -1;
           y = -1;
       }
       int id;
       string name, lname, add;
       private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
       {
           string s = dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString();
           id=Convert.ToInt32( dataGridView1 .Rows[e.RowIndex ].Cells[0].Value.ToString());
           name=dataGridView1.Rows[e.RowIndex].Cells[1].Value.ToString();
           lname = dataGridView1.Rows[e.RowIndex].Cells[2].Value.ToString();
           add = dataGridView1.Rows[e.RowIndex].Cells[3].Value.ToString();



       }

       private void btnupdate_Click(object sender, EventArgs e)
       {

           int done = obj.updat(id,name,lname,add);

       }

thanks and regards