private void btn_refresh_Click(object sender, EventArgs e)
        {
            // Data Grid View
            ManageUser vu = new ManageUser();
            DataTable  dt = vu.Select_user();

            dataGridView1.DataSource = dt;
        }
        private void ManageUser_Load(object sender, EventArgs e)
        {
            // Data Grid View
            ManageUser vu = new ManageUser();
            DataTable  dt = vu.Select_user();

            dataGridView1.DataSource = dt;
        }
        private void text_search_TextChanged(object sender, EventArgs e)
        {
            //Get keyword from textbox
            string     keyword = text_search.Text;
            ManageUser vu1     = new ManageUser();

            //Check if keywords have value or not
            if (keyword != null)
            {
                //show user based based on keywords
                DataTable dt = vu1.Search(keyword);
                dataGridView1.DataSource = dt;
            }
            else
            {
                //show all user from database
                DataTable dt = vu1.Select_user();
                dataGridView1.DataSource = dt;
            }
        }