“ sing”之后，ConnectionString属性尚未初始化。

无言的风

我的连接字符串、数据库和其他一切都正常工作，但当我在页面上调用它时。
2 M2 O! h- w9 f: L, O我有几种方法可以连接到数据库并返回给我一个值。这是我第一次需要使用两种方法。我得到了这个错误conn.Open()：
“ ConnectionString属性尚未初始化。
描述:目前正在执行Web未处理的异常发生在请求过程中。请查看堆栈跟踪，以获取代码中相关错误及其起源的详细信息。
6 P# ?! z( }( b异常细节：System.InvalidOperationException：ConnectionString属性尚未初始化。
2 O6 S' s. X2 e* I! t当我打电话时，只有一份工作做得很好。
我从这两种方法中得到的是，我为每个人使用几乎相同的代码，只是更改了表名：
public DataTable Category()()(()()()()(                      )sda = new SqlDataAdapter("select * from tbl_category",conn);        sda.Fill(dt);        return dt;}和
; a; x, Y  ]/ L, ^& N% s9 Cpublic int CategoryLastId(){     using (conn){        conn.Open()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；sqlCommand = new SqlCommand("SELECT MAX(Id) AS LastID FROM tbl_category",conn);       sqlCommand.ExecuteNonQuery()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；Int32 newId = (Int32)sqlCommand.ExecuteScalar()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；conn.Close()；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；；return Convert.ToInt32(newId);   }}感觉他们有冲突(也可以通过)NHibernate调用.Get，但也很好用)
                                                               
: {3 \$ v7 n% L7 e# H2 t2 ~    解决方案: