Question

我有这个代码

var now = DateTime.UtcNow;

var currentRoleInsights = dbContext.DocumentInsights.Where(dr =>
        dr.DocumentID == data.ID && 
        insightIDsToDelete.Contains(dr.InsightID)).ToList();

foreach (var r in currentRoleInsights)
{
    r.StatusID = StatusType.Deleted;
    r.DeletedByAMSUserID = amsUserID;
    r.DateDeleted = now;
}

现在，如果我再次使用以下代码查询：

var data = dbContext.DocumentInsights.Where(dr =>
    dr.DocumentID == data.ID && 
    insightIDsToDelete.Contains(dr.InsightID)).ToList();

我会得到状态已更新的数据吗？

请注意，我尚未调用dbContext.SaveChanges()，并且我不希望我的代码看起来像这样

var now = DateTime.UtcNow;

var currentRoleInsights = dbContext.DocumentInsights.Where(dr =>
        dr.DocumentID == data.ID && 
        insightIDsToDelete.Contains(dr.InsightID)).ToList();

foreach (var r in currentRoleInsights)
{
    r.StatusID = StatusType.Deleted;
    r.DeletedByAMSUserID = amsUserID;
    r.DateDeleted = now;
}

dbContext.SaveChanges()

var data = dbContext.DocumentInsights.Where(dr =>
    dr.DocumentID == data.ID && 
    insightIDsToDelete.Contains(dr.InsightID)).ToList();
// modify data

Answer 1

我会得到状态已更新的数据吗？

是

// @nuget: EntityFramework

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

public class Program
{
    public static void Main()
    {
        InsertData();

        using (var context = new BookStore())
        {
            var authors = context.Authors.Include(a => a.Books).ToList();

            DisplayData(authors);

            foreach(var a in authors){
                a.Books.ToList().ForEach(x=>x.Title = x.Title + " 2019");
            }

            Console.WriteLine();

            authors = context.Authors.Include(a => a.Books).ToList();
            DisplayData(authors);
        }

    }

    public static void DisplayData(List<Author> list)
    {
        foreach(var author in list)
        {
            Console.WriteLine("Author Name: " + author.Name);
            Console.WriteLine("\tBook List:");
            foreach(var book in author.Books)
            {
                Console.WriteLine("\t\t" + book.Title);
            }
        }
    }

    public static void InsertData()
    {
        using (var context = new BookStore())
        {
            Author author1 = new Author()
            {
                Name = "Mark",
                Books = new List<Book>
                {
                    new Book() { Title = "Fundamentals of Computer Programming with C#"},
                    new Book() { Title = "Java: A Beginner's Guide"},
                }
            };
            Author author2 = new Author()
            {
                Name = "Andy",
                Books = new List<Book>
                {
                    new Book() { Title = "SQL: The Ultimate Beginners Guide"}
                }
            };

            Author author3 = new Author()
            {
                Name = "Johny",
                Books = new List<Book>
                {
                    new Book() { Title = "Learn VB.NET"},
                    new Book() { Title = "C# Fundamentals for Absolute Beginners"},
                }
            };

            context.Authors.Add(author1);
            context.Authors.Add(author2);
            context.Authors.Add(author3);

            context.SaveChanges();
        }
    }

    public class BookStore : DbContext
    {
        public BookStore() : base(FiddleHelper.GetConnectionStringSqlServer())
        {
        }

        public DbSet<Author> Authors { get; set; }
        public DbSet<Book> Books { get; set; }
    }

    public class Book
    {
        public int Id { get; set; }
        public string Title { get; set; }
        public int AuthorId { get; set; }
        [ForeignKey("AuthorId")]
        public Author Author { get; set; }
    }

    public class Author
    {
        public int AuthorId { get; set; }
        public string Name { get; set; }
        public ICollection<Book> Books { get; set; }
    }
}

将上面的代码复制并粘贴到https://dotnetfiddle.net/

Linq-to-SQL dbContext数据

1 个答案: