cmd=new sqlcommand("select max(reg_code) from tbl_registration",con);
dr=cmd.ExecuteReader();
dr.Read();
if (dr.HasRows)
{
if (dr[0].ToString() != "")
{
maxNo = Int64.Parse(dr[0].ToString());
long b = (maxNo + 1);
if (b <= 9)
{
txtusercode.Text = "000" + b.ToString();
}
else if (b <= 99)
{
txtusercode.Text = "00" + b.ToString();
}
else if (b <= 999)
{
txtusercode.Text = "0" + b.ToString();
}
else if (b <= 9999)
{
txtusercode.Text = b.ToString();
}
dr.Close();
}
else
{
txtusercode.Text = "0001";
dr.Close();
}
}
else
{
dr.Close();
txtusercode.Text = "0001";
}