View Code 
1 using (SqlConnection con = new SqlConnection(strcon))
2 {
3      string sql = "select * from Forums where ForumID=1";
4      SqlCommand cmd = new SqlCommand(sql, con);
5      con.Open();
6      SqlDataReader reader = cmd.ExecuteReader();
7      Response.Write(reader[0]);         
8 }


报错：

在没有任何数据时进行无效的读取尝试。

 

原来，reader是向下读取的

 

View Code 
 1 using (SqlConnection con = new SqlConnection(strcon))
 2 {
 3         string sql = "select * from Forums where ForumID=1";
 4         SqlCommand cmd = new SqlCommand(sql, con);
 5         con.Open();
 6         SqlDataReader reader = cmd.ExecuteReader();
 7         while (reader.Read())
 8         {
 9                Response.Write(reader[0]);
10          }
11             
12 }

 

这样就ok了