I am trying to connect sql anywhere12 database to my .net project but while connecting to the database but the connection can not be opened

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using iAnywhere.Data.SQLAnywhere;

namespace myproject1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btncon_Click(object sender, EventArgs e)
        {
         string connetionString = null;
         SAConnection connection = new SAConnection();
         SACommand command;
            //string sqla = null;
         connetionString = " ENG=demo12;UID=dba;PWD=sql;DBN=sql;LINKS=TCPIP";

         //  sqla = "INSERT INTO  Student(Rollnumber,Name) values('" + textBox1.Text + "','" + textBox2.Text + "')";
           // sqla = "SELECT * FROM Contacts";
            connection = new SAConnection(connetionString);
            try
            {
                connection.Open();
                command = new SACommand("SELECT * FROM Contacts", connection);
                command.ExecuteNonQuery();
                command.Dispose();
                connection.Close();
                MessageBox.Show(" ExecuteNonQuery in SqlCommand executed !!");
            }
            catch (Exception )
            {
                MessageBox.Show("Can not open connection ! ");
            }

        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

please help me why this things are happening inside the program im just a beginner in sql anywhere