用LINQ打印一个表格

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问题描述

我是 LINQ 编程的初学者，我想知道如何使用控制台应用程序中的 LINQ 打印表(在 SQL Server 中)中的所有数据.到目前为止，我所做的是创建一个名为 Response 的表，该表具有多个字段(我在 SQL Server Management Studio 中设计了该表)并编写了一个控制台 C# 类来打印所有值.这是我的代码:

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

namespace LinqConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            using (DatabaseDBDataContext responses = new DatabaseDBDataContext()) 
            {
                IEnumerable<Response> responses = from response in responses.Responses select response; 

                foreach (Response response in responses)
                {

                    Console.WriteLine(response);
                }
                Console.ReadKey();
            }

        }
    }
}

但是，当我在 cmd 中运行它时，我会得到它作为我的输出:

LinqConsoleApplication.Response

通过谷歌搜索某些解决方案，我发现 Console.WriteLine(response) 应该从表中返回 EVERYTHING (select *)，但似乎并非如此.请问有什么建议吗?我构建查询的方式是否有错误?我需要使用 StringBuilder 方法将每个字段附加到 writeLine() 吗?

推荐答案

你可以使用反射来做到这一点.确保你正在使用System.Reflection.

static void Main(string[] args)
{
  using (AcumenProjectsDBDataContext acumenResponse = new AcumenProjectsDBDataContext()) 
  {
    IEnumerable<Response> responseData = from response in acumenResponse.Responses select response; 
    //added code
     foreach (Response response in responseData)
     {
        foreach (PropertyInfo prop in response.GetType().GetProperties(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
        {
          object value = prop.GetValue(response, new object[] { });
          Console.WriteLine("{0} = {1}", prop.Name, value);
        }
      }
      Console.ReadKey();
   }

}

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问题描述

I am a starter with programming in LINQ and I would like to know how I can print all the data from a table (in SQL Server) using LINQ from a console application. What I have done till now is to create a table called Response which has several fields (I have designed the table in SQL Server Management Studio) and have written a console C# class to print all the values out. Here's my code for that:

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

namespace LinqConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            using (DatabaseDBDataContext responses = new DatabaseDBDataContext()) 
            {
                IEnumerable<Response> responses = from response in responses.Responses select response; 

                foreach (Response response in responses)
                {

                    Console.WriteLine(response);
                }
                Console.ReadKey();
            }

        }
    }
}

However, when I run this in cmd, I get this as my output:

LinqConsoleApplication.Response

From googling for some solutions, I have found that Console.WriteLine(response) should return EVERYTHING (select *) from a table, but that doesn't seem to be the case. Any suggestions please? Is there an error in the way I have framed the query? Will I need to use a StringBuilder method to append each and every field to the writeLine()?

推荐答案

You can do this with using reflection.Make sure you're using System.Reflection.

static void Main(string[] args)
{
  using (AcumenProjectsDBDataContext acumenResponse = new AcumenProjectsDBDataContext()) 
  {
    IEnumerable<Response> responseData = from response in acumenResponse.Responses select response; 
    //added code
     foreach (Response response in responseData)
     {
        foreach (PropertyInfo prop in response.GetType().GetProperties(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
        {
          object value = prop.GetValue(response, new object[] { });
          Console.WriteLine("{0} = {1}", prop.Name, value);
        }
      }
      Console.ReadKey();
   }

}

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