为何我的插入就是不行呢？？？

高手请指教一下，当我点击“添加”的时候，就是不行，麻烦能否给指点一下？谢谢。
public static bool insertOperate(oil y)
        {
            try
            {
                
                SqlConnection con=oilOperate.createCon();
                con.Open();
//                SqlCommand cmd=new SqlCommand("insert into price  values(y.DateTime,y.Categories,y.Products,y.TodayPrices,y.PreviousDay,y.Remarks,y.Units,y.messagePerson,y.messageUnit,y.visiable)",con);
                
                SqlCommand cmd=new SqlCommand("insert into Price values(@DateTime,@Categories,@Products,@TodayPrices,@PreviousDay,@Remarks,@Units,@messagePerson,@messageUnit,@visiable)",con);
                SqlParameter para=new SqlParameter("@DateTime",SqlDbType.SmallDateTime,4);
                para.Value=y.DateTime;
                cmd.Parameters.Add(para);

                para=new SqlParameter("@Categories",SqlDbType.VarChar,20);
                para.Value=y.Categories;
                cmd.Parameters.Add(para);

                para=new SqlParameter("@Products",SqlDbType.VarChar,20);
                para.Value=y.Products;
                cmd.Parameters.Add(para);

                para=new SqlParameter("@TodayPrices",SqlDbType.VarChar,20);
                para.Value=y.TodayPrices;
                cmd.Parameters.Add(para);

                para=new SqlParameter("@PreviousDay",SqlDbType.VarChar,20);
                para.Value=y.PreviousDay;
                cmd.Parameters.Add(para);

                para=new SqlParameter("@Remarks",SqlDbType.VarChar,50);
                para.Value=y.Remarks;
                cmd.Parameters.Add(para);

                para=new SqlParameter("@Units",SqlDbType.VarChar,20);
                para.Value=y.Units;
                cmd.Parameters.Add(para);

                para=new SqlParameter("@messagePerson",SqlDbType.VarChar,50);
                para.Value=y.messagePerson;
                cmd.Parameters.Add(para);

                para=new SqlParameter("@messateUnit",SqlDbType.VarChar,50);
                para.Value=y.messageUnit;
                cmd.Parameters.Add(para);
            
                para=new SqlParameter("@visiable",SqlDbType.VarChar,10);
                para.Value=y.visiable;
                cmd.Parameters.Add(para);

                cmd.ExecuteNonQuery();
                return true;
            }
            catch(Exception e)
            {
                return false;
            }
            
        }