如何克隆POCO实体，并添加上下文 [英] How to Clone POCO entity and add to context

问题描述

我用EF4，我有创建POCO从我的数据库结构代理的对象。我有一个POCO（对象），其中有很多到其他实体的关系。

我创建使用的DataContractSerializer和BinaryFormatter的对象的深层副本，并允许调用它clonedObject。<用于克隆/ p>

功能：

 公共牛逼CloneProxy< T> （T源）
 {
变种DCS =新System.Runtime.Serialization 
 .DataContractSerializer（typeof运算（T））; 
字符串文件路径=Initiative.txt;使用（的FileStream文件=新的FileStream（文件路径，FileMode.Create））
 {
（新的BinaryFormatter（））
 
序列化（文件，源）。 
} 
 
 context.CreateProxyTypes（新类型[] {typeof运算（倡议）}）; 。使用（的FileStream文件=新的FileStream（文件路径，FileMode.Open））
 {
回报率（T）
 
（新的BinaryFormatter（））反序列化（文件）; 
} 
 
} 
  

现在，我有clonedObject，怎么我将其添加到上下文？ ？我怎么把它添加到数据库中。

我对象（只是给你的POCO倡议的想法）：

 倡议
 {
 InitI 
 InitName 
<收缴>评论
} 
评论
 {
 CommentI 
< FK> InitI 
} 
  

这里有一些我已经收到我做的方式和错误

  cloneInit.InitI = 0。 
 
 Data_Business.RQRMComment [] =改编新Data_Business.RQRMComment [1]; 
 
 ARR = cloneInit.RQRMComments.ToArray（）; 
 
的for（int x = 0; X< arr.Length; X ++）//每一个（VAR在cloneInit.RQRMComments X）
 {
 RQRMComment thisC = ARR [X ]; 
 INT Y = thisC.InitI; 
 thisC.InitI = 0; 
 thisC.ID = 0; 
} 
 Context.AddObject（倡议，cloneInit）; 
 Context.SaveChanges（System.Data.Objects.SaveOptions.AcceptAllChangesAfterSave）; 
  

错误：

离= {对象不能添加或连接，因为它的EntityReference具有不匹配的EntityKey此对象的的EntityKey属性值。}

请帮帮忙，我已经花了太多时间在这。谢谢你。

解决方案

我有需要克隆我的实体为宗旨，以重新显示表单上的数据，以便用户可以选择创建和放大器;添加类似。在努力减少工作的用户需要，以添加范围，类似的项目，我的DB的花费金额

我查了几个选项，包括反射&安培;序列化，但它们是凌乱了什么，我想实现的，然后我发现我可以克服XYZ是对象的关键信息的一部分，并且不能被修改的问题 - 即把我的实体主键0插入后（保存更改） - 用下面的代码：

  MyDbEntities BB =新MyDbEntities（）; 
 
 //添加和放大器;保存新的条目
 db.Product.AddObject（产品）; 
 db.SaveChanges（）; 
 
 //复位实体
 db.ObjectStateManager.ChangeObjectState（产品，System.Data.EntityState.Added）; 
 product.ProductId = 0; 
  

I am using EF4 and I have create POCO objects with proxies from my database structure . I have a POCO (object) which has lots of relationships to other entities.

I created a deep copy of the object using DataContractSerializer and BinaryFormatter and lets call it clonedObject.

function used for cloning is:

public T CloneProxy<T>(T source)
{
  var dcs = new System.Runtime.Serialization
     .DataContractSerializer(typeof(T));
  string filePath = "Initiative.txt";

  using (FileStream file = new FileStream(filePath, FileMode.Create))
  {
    (new BinaryFormatter()).Serialize(file, source);
  }

  context.CreateProxyTypes(new Type[] { typeof(Initiative) });

  using (FileStream file = new FileStream(filePath, FileMode.Open))
  {
    return (T)(new BinaryFormatter()).Deserialize(file);
  }

}

Now that I have clonedObject, how do I add it to the context? how do I add it to the database?

my object (just giving you an Idea of the POCO Initiative):

Initiative
{   
InitI   
InitName    
<collection>Comments
}    
Comments    
{    
CommentI    
<FK>InitI   
}

Here are some of the way I have done and errors I have received.

cloneInit.InitI = 0;

    Data_Business.RQRMComment[] arr = new Data_Business.RQRMComment[1];

    arr = cloneInit.RQRMComments.ToArray();

    for (int x = 0; x < arr.Length; x++) //each (var x in cloneInit.RQRMComments)
    {
      RQRMComment thisC = arr[x];
      int y = thisC.InitI;
      thisC.InitI = 0;
      thisC.ID = 0;
    } 
    Context.AddObject("Initiatives", cloneInit); 
    Context.SaveChanges(System.Data.Objects.SaveOptions.AcceptAllChangesAfterSave);

Error:

ex = {"The object could not be added or attached because its EntityReference has an EntityKey property value that does not match the EntityKey for this object."}

Please help, I have spent too much time on this. Thank you.

解决方案

I have had a need to clone my Entities for the purpose of re-displaying the data on a form so that a user can choose to "Create & Add Similar" in an effort to reduce the amount of effort a user needs to expend in order to add a range of similar items to my DB.

I checked out a few options including reflection & serialization but they are messy for what I am trying to achieve, I then discovered that I can overcome the "XYZ is part of the object's key information and cannot be modified" issue - i.e. set my entities primary key to 0 after insert (Save Changes) - with the following code:

MyDbEntities bb = new MyDbEntities();

 //Add & Save new entry
 db.Product.AddObject(product);
 db.SaveChanges();

 //Reset entity
 db.ObjectStateManager.ChangeObjectState(product, System.Data.EntityState.Added);
 product.ProductId = 0;

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