public partial class Register : System.Web.UI.Page{

public string ID, Pass, Email, BDYear, BDMonth, BDDay, FullName;
SqlCommand cmd;
SqlConnection con;
SqlDataAdapter da;
protected void Page_Load(object sender, EventArgs e)
{


    if (IsPostBack){

        ID = Request.Form["ID"];
        Pass = Request.Form["PW"];
        Email = Request.Form["EMAIL"];
        BDYear = Request.Form["BDYear"];
        BDMonth = Request.Form["BDMonth"];
        BDDay = Request.Form["BDDay"];
        FullName = Request.Form["FullName"];

        cmd = new SqlCommand("INSERT INTO UserInfo (ID, Pass, Email, BDYear, BDMonth, BDDay, FullName) VALUES (ID, Pass, Email,BDYear, BDMonth, BDDay, FullName)");

    }

}

cmd = new SqlCommand("INSERT INTO UserInfo (ID, Pass, Email, BDYear, BDMonth, BDDay, FullName) VALUES ("+ID+", "+Pass+", "+Email+","+BDYear+", "+BDMonth+", "+BDDay+", "+FullName+")");