如何清理实体框架对象上下文？ [英] How to clean-up an Entity Framework object context?

问题描述

我添加几个实体对象上下文。

I am adding several entities to an object context.

try
{
    forach (var document in documents)
    {
        this.Validate(document); // May throw a ValidationException.

        this.objectContext.AddToDocuments(document);
    }

    this.objectContext.SaveChanges();
}
catch
{
    // How to clean-up the object context here?

    throw;
}

如果一些文件通过验证，一个失败，所有文档通过了验证保持添加到对象上下文。我要清理对象上下文，因为它可以重复使用，会出现以下情况。

If some of the documents pass the the validation and one fails, all documents that passed the validation remain added to the object context. I have to clean-up the object context because it may be reused and the following can happen.

var documentA = new Document { Id = 1, Data = "ValidData" };
var documentB = new Document { Id = 2, Data = "InvalidData" };
var documentC = new Document { Id = 3, Data = "ValidData" };

try
{
    // Adding document B will cause a ValidationException but only
    // after document A is added to the object context.
    this.DocumentStore.AddDocuments(new[] { documentA, documentB, documentC });
}
catch (ValidationException)
{
}

// Try again without the invalid document B. This causes an exception because
// of a duplicate primary key - document A with id 1 is added a second time.
this.DocumentStore.AddDocuments(new[] { documentA, documentC });

这将再次文件A添加到对象上下文，并在后果的SaveChanges（ ）将抛出，因为重复的主键的一个例外。

This will again add document A to the object context and in consequence SaveChanges() will throw an exception because of a duplicate primary key.

所以，我必须删除所有已添加的文档在验证错误的情况下， 。我当然可以先进行验证和只添加的所有文件后，他们已经被成功验证，但可悲的是这并没有解决整个问题 - 如果的SaveChanges（）失败，所有的文件仍保持增加，但尚未保存的。

So I have to remove all already added documents in the case of an validation error. I could of course perform the validation first and only add all documents after they have been successfully validated but sadly this does not solve the whole problem - if SaveChanges() fails, all documents still remain added but unsaved.

我企图吞并由

 this.objectContext.ObjectStateManager.GetObjectStateEntries(EntityState.Added)

但我得到一个例外说明该对象未连接。那么，如何摆脱所有添加，但尚未保存的对象？

but I am getting a exception stating that the object is not attached. So how do I get rid of all added but unsaved objects?

推荐答案

这只是一个微不足道的错误，但我要离开这里的问题 - 也许它可以帮助别人

It was just a trivial bug but I am going to leave the question here - maybe it helps others.

我有以下

var objectStateEntries = this.objectContext
                             .ObjectStateManager
                             .GetObjectStateEntries(EntityState.Added);

foreach (var objectStateEntry in objectStateEntries)
{
    this.objectContext.Detach(objectStateEntry);
}

而我想以下

while I wanted the following

foreach (var objectStateEntry in objectStateEntries)
{
    this.objectContext.Detach(objectStateEntry.Entity);
}

和无法看到它。

这篇关于如何清理实体框架对象上下文？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！