c# - 数据读取器初始化(再次)

Question

我收到数据读取器初始化错误。我知道这个问题以前已经回答过很多次了，但这些案例似乎不适合我的情况。错误消息开头为“执行读取器:连接属性尚未初始化。”

程序:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;

namespace BookList   

{
    class Program
    {
        static void Main(string[] args)
        {
            SqlConnection dataConnection = new SqlConnection();
            dataConnection.ConnectionString = "Integrated Security = true; Initial Catalog = BIBLIOGRAPHY;Data Source = JBSHAPIRO-PC\\SQLEXPRESS";

            dataConnection.Open();
            Console.Write("Enter author's name: ");
            string person = Console.ReadLine();




            SqlCommand datacommand = new SqlCommand();
            datacommand.CommandText = "SELECT AUTHOR, TITLE, YEAR, KEYWORDS 

FROM BOOKS WHERE AUTHOR = ' " + person + " ' ";


            Console.WriteLine("About to Execute: {0}\n\n", 

datacommand.CommandText);


            SqlDataReader dataReader = datacommand.ExecuteReader();

            while (dataReader.Read())
            {
                string author1 = dataReader.GetString(0);
                string title1 = dataReader.GetString(1);
                int year1 = dataReader.GetInt32(2);
                string keywords1 = dataReader.GetString(3);

                Console.WriteLine(
                    "Author: {0}\n, Title: {1}\n, Year: {2}\n; Key Words: {4)\n\n",
                author1, title1, year1, keywords1);
                dataReader.Close();
            }
            dataConnection.Close();
        }
    }
}

代码适用于为 C# 3 编写的不同数据库，但我现在尝试使用 C# 6。有什么建议吗？

Answer 1

您从未将 SqlCommand 与连接关联起来:

SqlCommand datacommand = new SqlCommand();
datacommand.Connection = dataConnection;

没有它，命令(以及扩展的数据读取器)不知道任何要使用的连接。