SqlConnection con = LinkDB.CreateConnection();
con.Open();
SqlDataAdapter sda = new SqlDataAdapter("Select FirmNo,Named from T04_Firms order by FirmNo", con);
DataSet ds = new DataSet();
sda.Fill(ds, "Firms");
datagridview1.DataSource = ds.Tables["Frims"].DefaultView;
为什么这句会出现“未将对象引用设置到对象的实例。”的错误？