private void button2_Click(object sender, EventArgs e)
{
int n = int.Parse(txtid.Text);
studint s = db.studint.FirstOrDefault(y => y.id == (n));
txtadrs.Text = s.adress;
txtage.Text = s.age.ToString();
txtname.Text = s.name;
}
private void add_studentdata()
{
studint s = new studint();
s.name = txtname.Text;
s.age = int.Parse(txtage.Text);
s.adress = txtadrs.Text;
db.studint.Add(s);
db.SaveChanges();
MessageBox.Show("datasaved bay");
}