Change your Display() Method by this way:
private void display(DataTable tbl)
{
txtempid.Text = tbl.Rows[0][1].ToString();
txtname.Text = tbl.Rows[0][2].ToString();
txtsurname.Text = tbl.Rows[0][3].ToString();
txtfathername.Text = tbl.Rows[0][4].ToString();
dtdob.Text = tbl.Rows[0][5].ToString();
cbgender.Text = tbl.Rows[0][6].ToString();
cbcity.Text = tbl.Rows[0][7].ToString();
txtcontactno.Text = tbl.Rows[0][8].ToString();
dtdoj.Text = tbl.Rows[0][9].ToString();
txtdept.Text = tbl.Rows[0][10].ToString();
txtdesig.Text = tbl.Rows[0][11].ToString();
txtqualification.Text = tbl.Rows[0][12].ToString();
rtaddress.Text = tbl.Rows[0][13].ToString();
rtremarks.Text = tbl.Rows[0][14].ToString();
}
Then in main method:
display(tbl);