LINQ代碼結合兩個數據庫表？

Question

所以我有一個表，我在一個網站上顯示，通過一些LINQ代碼從數據庫獲取所有信息。 表“db.Log”包含一些內容和一個外鍵customerId ，它鏈接到名為dbo.customers的數據庫中的Id （它只有Id和customerName） ，我希望LINQ代碼將這兩者結合起來，所以我除非你全部知道，否則可以在表格中填寫客戶的姓名，而不是真正說不出任何內容的ID。 以下是當前代碼：

LogModelsController.cs

message = (from log 
           in db.Log 
           select log);

int pageSize = 10;
int pageNumber = (page ?? 1);

return View(message.OrderByDescending(i => i.timeStamp).ToPagedList(pageNumber, pageSize));

LogModel.cs

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;

namespace ASDMVC.Models
{
    [Table("Log")]
    public class LogModel
    {
        [Key]
        public long id { get; set; }
        public string message { get; set; }
        public DateTime timeStamp { get; set; }
        public string level { get; set; }
        public int customerId { get; set; }
    }

    public class LogDBContext:DbContext
    {
        public LogDBContext() : base("MySqlConnection")
        {

        }

        public DbSet <LogModel> Log { get; set; }

    }
}

我對LINQ代碼很新，請原諒我，任何幫助都將不勝感激。

提前致謝。

編輯：NewCustomerModel.cs

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;
using System.Web.Mvc;

namespace ASDMVC.Models
{
    [Table("Customers")]
    public class NewCustomerModel
    {
        [Key]
        public int Id { get; set; }
        [Display(Name = "Customer Id")]
        public int CustomerId { get; set; }
        public string CustomerName { get; set; }
    }

    public class CustomerDBContext : DbContext
    {
        public CustomerDBContext() : base("MySqlConnection")
        {

        }
        public DbSet<NewCustomerModel> Customers { get; set; }
    }
}

我認為（在與朋友交談后）需要這種模式 - 可能完全錯誤。

---

用戶1666620建議后的代碼

LogModelsController.cs

message = (from log in db.Log join customers in dbo.Customers on log.customerId equals customers.Id select log);

int pageSize = 10;
int pageNumber = (page ?? 1);

return View(message.OrderByDescending(i => i.timeStamp).ToPagedList(pageNumber, pageSize));

LogModel.cs

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;

namespace ASDMVC.Models
{
    [Table("Log")]
    public class LogModel
    {
        [Key]
        public long id { get; set; }
        public string message { get; set; }
        public DateTime timeStamp { get; set; }
        public string level { get; set; }
        public int customerId { get; set; }
        public int customerName { get; set; }
    }

    public class LogDBContext:DbContext
    {
        public LogDBContext() : base("MySqlConnection")
        {

        }

        public DbSet <LogModel> Log { get; set; }

    }
}

有錯誤：

指定的LINQ表達式包含對與不同上下文關聯的查詢的引用。

Answer 1

這應該為你做：

var message = (from log in db.Log
               join customers in dbo.customers on log.customerid equals customers.Id
               select log); 

在上面，沒有必要明確使用where子句，因為在連接中處理。

如果您只想返回特定列，可以執行以下操作：

var message = (from log in db.Log
               join customers in dbo.customers on log.customerid equals customers.Id
               select new { customerId = customers.Id, logId = log.id }); 

如果你想在兩個上下文之間進行連接，請看一下這個解決方法： 模擬交叉上下文連接 - LINQ / C＃

Answer 2

控制器：

message = db.GetLogs();

int pageSize = 10;
int pageNumber = (page ?? 1);
var logs = message.OrderByDescending(i => i.timeStamp).ToPagedList(pageNumber, pageSize);

foreach (var log in logs)
    log.Name = Customer.Where(a => a.Value == log.customerId.ToString()).FirstOrDefault().Text;
                return PartialView("_LogPartialLayout", logs);

模型：

using System;
using System.Linq;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;
using System.Collections.Generic;
using System.Web.Mvc;

namespace ASDMVC.Models
{
    [Table("Log")]
    public class LogModel
    {
        [Key]
        public long id { get; set; }
        public string message { get; set; }
        public DateTime timeStamp { get; set; }
        public string level { get; set; }
        public int customerId { get; set; }
        [NotMapped]
        public string Name { get; set; }
    }

    public class LogDBContext:DbContext
    {
        public LogDBContext() : base("MySqlConnection")
        {

        }

        public DbSet <LogModel> Log { get; set; }

        public IQueryable<LogModel> GetLogs()
        {
            return from log in Log
                   select log;
        }
    }
}