在EF 7中，您可以使用批量删除

    var ids = widgets.Select(x => x.Id).ToList();
    await _mrVodDbContext.Widgets.Where(x => ids.Contains(x.Id)).ExecuteDeleteAsync();

EF磁芯发生器

  DELETE FROM [i]
  FROM [Widgets] AS [i]
  WHERE [i].[Id] IN (4,3,2,1)

更多关于在发行说明中删除或更新的信息。https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-7.0/whatsnew#basic-executedelete-examples

如果您正在使用通用存储库:

在泛型存储库中，下面可能是新方法。

       public void RemoveMultiple(Expression<Func<T, bool>> predicate)
        {
             IQueryable<T> query = _context.Set<T>().Where(predicate);
             _context.Set<T>().RemoveRange(query.AsNoTracking());
            
        }

用法:

_unitOfWork.YOUR_ENTITY.RemoveMultiple(x => x.AccountId == accountId);
 _unitOfWork.Complete();

最快的删除方法是使用存储过程。与动态SQL相比，我更喜欢数据库项目中的存储过程，因为重命名将被正确处理，并且有编译器错误。动态SQL可以引用已删除/重命名而导致运行时错误的表。

在本例中，我有两个表List和ListItems。我需要一个快速的方法来删除给定列表的所有ListItems。

CREATE TABLE [act].[Lists]
(
    [Id] INT NOT NULL PRIMARY KEY IDENTITY, 
    [Name] NVARCHAR(50) NOT NULL
)
GO
CREATE UNIQUE INDEX [IU_Name] ON [act].[Lists] ([Name])
GO
CREATE TABLE [act].[ListItems]
(
    [Id] INT NOT NULL IDENTITY, 
    [ListId] INT NOT NULL, 
    [Item] NVARCHAR(100) NOT NULL, 
    CONSTRAINT PK_ListItems_Id PRIMARY KEY NONCLUSTERED (Id),
    CONSTRAINT [FK_ListItems_Lists] FOREIGN KEY ([ListId]) REFERENCES [act].[Lists]([Id]) ON DELETE CASCADE
)
go
CREATE UNIQUE CLUSTERED INDEX IX_ListItems_Item 
ON [act].[ListItems] ([ListId], [Item]); 
GO

CREATE PROCEDURE [act].[DeleteAllItemsInList]
    @listId int
AS
    DELETE FROM act.ListItems where ListId = @listId
RETURN 0

现在有趣的部分是使用扩展删除项目和更新Entity框架。

public static class ListExtension
{
    public static void DeleteAllListItems(this List list, ActDbContext db)
    {
        if (list.Id > 0)
        {
            var listIdParameter = new SqlParameter("ListId", list.Id);
            db.Database.ExecuteSqlCommand("[act].[DeleteAllItemsInList] @ListId", listIdParameter);
        }
        foreach (var listItem in list.ListItems.ToList())
        {
            db.Entry(listItem).State = EntityState.Detached;
        }
    }
}

现在可以使用的主要代码是as

[TestMethod]
public void DeleteAllItemsInListAfterSavingToDatabase()
{
    using (var db = new ActDbContext())
    {
        var listName = "TestList";
        // Clean up
        var listInDb = db.Lists.Where(r => r.Name == listName).FirstOrDefault();
        if (listInDb != null)
        {
            db.Lists.Remove(listInDb);
            db.SaveChanges();
        }

        // Test
        var list = new List() { Name = listName };
        list.ListItems.Add(new ListItem() { Item = "Item 1" });
        list.ListItems.Add(new ListItem() { Item = "Item 2" });
        db.Lists.Add(list);
        db.SaveChanges();
        listInDb = db.Lists.Find(list.Id);
        Assert.AreEqual(2, list.ListItems.Count);
        list.DeleteAllListItems(db);
        db.SaveChanges();
        listInDb = db.Lists.Find(list.Id);
        Assert.AreEqual(0, list.ListItems.Count);
    }
}

实体框架核心

3.1 3.0 2.2 2.1 2.0 1.1 1.0

using (YourContext context = new YourContext ())
{
    var widgets = context.Widgets.Where(w => w.WidgetId == widgetId);
    context.Widgets.RemoveRange(widgets);
    context.SaveChanges();
}

简介:

从集合下面的上下文中移除给定的实体集合 每个实体都处于已删除状态，这样它就会被删除 当SaveChanges被调用时，从数据库中获取。

备注:

Note that if System.Data.Entity.Infrastructure.DbContextConfiguration.AutoDetectChangesEnabled is set to true (which is the default), then DetectChanges will be called once before delete any entities and will not be called again. This means that in some situations RemoveRange may perform significantly better than calling Remove multiple times would do. Note that if any entity exists in the context in the Added state, then this method will cause it to be detached from the context. This is because an Added entity is assumed not to exist in the database such that trying to delete it does not make sense.

using (var context = new DatabaseEntities())
{
    context.ExecuteStoreCommand("DELETE FROM YOURTABLE WHERE CustomerID = {0}", customerId);
}

新增:支持可编写的id列表

var listOfIds = String.Join(',',customerIds.Select(id => $"'{id}'").ToList());
var sql= $@"DELETE  [YOURTABLE] WHERE CustomerID in ({listOfIds})";

注意:如果CustomerID是一个字符串，您应该仔细检查潜在的SQL注入风险，对于整数CustomerID是安全的

EntityFramework 6使用. removerange()使这变得更容易一些。

例子:

db.People.RemoveRange(db.People.Where(x => x.State == "CA"));
db.SaveChanges();

警告!不要在大型数据集上使用此方法!

EF将所有数据拉入内存，然后删除它。对于较小的数据集，这可能不是一个问题，但通常避免这种类型的删除，除非你能保证你只做非常小的更改。

您可以很容易地将进程运行到内存不足的状态，而EF会很高兴地提取您指定的所有数据来删除它。