C# EF：包含所有子对象（包括子子对象）的复制对象（深度复制）
我有一个具有如下属性的表：C# EF：包含所有子对象（包括子子对象）的复制对象（深度复制）,c#,entity-framework,linq,linq-to-entities,C#,Entity Framework,Linq,Linq To Entities,我有一个具有如下属性的表： Id Name ParentId ParentId是主列Id的外键。现在让我们假设我有几行，如：（仅显示来自行的ParentId） 现在，假设我们要复制其ParentId为空的行对象及其所有子对象 var row = db.FirstOrDefault(x=> x.Id == 1); var new_row = new Table1(); var subrows = row.Table1.ToArray(); foreach(var
Id Name ParentIdParentIdIdParentIdParentId var row = db.FirstOrDefault(x=> x.Id == 1);
var new_row = new Table1();
var subrows = row.Table1.ToArray();
foreach(var row in subrows)
{
db.Entry(row).State = System.Data.Entity.EntityState.Detached;
}
new_row.Table1 = subrows;
db.Table.Add(new_row);
db.saveChanges();
NULL
/ \
1 2
private void RecursiveDetach(Table1 parent)
{
var subrows = parent.Table1.ToArray();
foreach (var row in subrows)
{
if(row.Table1.Count() > 0)
{
RecursiveDetach(row);
}
db.Entry(row).State = System.Data.Entity.EntityState.Detached;
}
}
我以前不得不这么做。我完全是在代码中完成的，递归地复制对象并在需要的地方清理惟一的ID，但我所构建的最干净的方法是将对象序列化为XML，然后反序列化为新对象。这种方法效率较低，但非常灵活，易于实现
//Save object to XML file. Returns filename.
public string SaveObjectAsXML(int id)
{
//however you get your EF context and disable proxy creation
var db = GetContext();
bool currentProxySetting = db.Configuration.ProxyCreationEnabled;
db.Configuration.ProxyCreationEnabled = false;
//get the data
var item = db.GetItem(id); //retrieval be unique to your setup, but I have
//a more generic solution if you need it. Make
//sure you have all the sub items included
//in your object or they won't be saved.
db.Configuration.ProxyCreationEnabled = currentProxySetting;
//if no item is found, do whatever needs to be done
if (item == null)
{
return string.Empty;
}
//I actually write my data to a file so I can save states if needed, but you could
//modify the method to just spit out the XML instead
Directory.CreateDirectory(DATA_PATH); //make sure path exists to prevent write errors
string path = $"{DATA_PATH}{id}{DATA_EXT}";
var bf = new BinaryFormatter();
using (FileStream fs = new FileStream(path, FileMode.Create))
{
bf.Serialize(fs, repair);
}
return path;
}
//Load object from XML file. Returns ID.
public int LoadXMLData(string path)
{
//make sure the file exists
if (!File.Exists(path))
{
throw new Exception("File not found.");
}
//load data from file
try
{
using (FileStream fs = new FileStream(path, FileMode.Open))
{
var item = (YourItemType)new BinaryFormatter().Deserialize(fs);
db.YourItemTypes.Add(item);
db.SaveChanges();
return item.Id;
}
}
catch (Exception ex) {
//Exceptions here are common when copying between databases where differences in config entries result in mis-matches
throw;
}
}
//save object
var savedObjectFilename = SaveObjectAsXML(myObjID);
//loading the item will create a copy
var newID = LoadXMLData(savedObjectFilename);
祝你好运 我以前不得不这么做。我完全是在代码中完成的，递归地复制对象并在需要的地方清理惟一的ID，但我所构建的最干净的方法是将对象序列化为XML，然后反序列化为新对象。这种方法效率较低，但非常灵活，易于实现
//Save object to XML file. Returns filename.
public string SaveObjectAsXML(int id)
{
//however you get your EF context and disable proxy creation
var db = GetContext();
bool currentProxySetting = db.Configuration.ProxyCreationEnabled;
db.Configuration.ProxyCreationEnabled = false;
//get the data
var item = db.GetItem(id); //retrieval be unique to your setup, but I have
//a more generic solution if you need it. Make
//sure you have all the sub items included
//in your object or they won't be saved.
db.Configuration.ProxyCreationEnabled = currentProxySetting;
//if no item is found, do whatever needs to be done
if (item == null)
{
return string.Empty;
}
//I actually write my data to a file so I can save states if needed, but you could
//modify the method to just spit out the XML instead
Directory.CreateDirectory(DATA_PATH); //make sure path exists to prevent write errors
string path = $"{DATA_PATH}{id}{DATA_EXT}";
var bf = new BinaryFormatter();
using (FileStream fs = new FileStream(path, FileMode.Create))
{
bf.Serialize(fs, repair);
}
return path;
}
//Load object from XML file. Returns ID.
public int LoadXMLData(string path)
{
//make sure the file exists
if (!File.Exists(path))
{
throw new Exception("File not found.");
}
//load data from file
try
{
using (FileStream fs = new FileStream(path, FileMode.Open))
{
var item = (YourItemType)new BinaryFormatter().Deserialize(fs);
db.YourItemTypes.Add(item);
db.SaveChanges();
return item.Id;
}
}
catch (Exception ex) {
//Exceptions here are common when copying between databases where differences in config entries result in mis-matches
throw;
}
}
//save object
var savedObjectFilename = SaveObjectAsXML(myObjID);
//loading the item will create a copy
var newID = LoadXMLData(savedObjectFilename);
祝你好运 这里有第二个完全不同的答案：递归地分离整个对象，而不仅仅是父对象。以下内容是作为上下文对象的扩展方法编写的：
/// <summary>
/// Recursively detaches item and sub-items from EF. Assumes that all sub-objects are properties (not fields).
/// </summary>
/// <param name="item">The item to detach</param>
/// <param name="recursionDepth">Number of levels to go before stopping. object.Property is 1, object.Property.SubProperty is 2, and so on.</param>
public static void DetachAll(this DbContext db, object item, int recursionDepth = 3)
{
//Exit if no remaining recursion depth
if (recursionDepth <= 0) return;
//detach this object
db.Entry(item).State = EntityState.Detached;
//get reflection data for all the properties we mean to detach
Type t = item.GetType();
var properties = t.GetProperties(BindingFlags.Public | BindingFlags.Instance)
.Where(p => p.GetSetMethod()?.IsPublic == true) //get only properties we can set
.Where(p => p.PropertyType.IsClass) //only classes can be EF objects
.Where(p => p.PropertyType != typeof(string)) //oh, strings. What a pain.
.Where(p => p.GetValue(item) != null); //only get set properties
//if we're recursing, we'll check here to make sure we should keep going
if (properties.Count() == 0) return;
foreach (var p in properties)
{
//handle generics
if (p.PropertyType.IsGenericType)
{
//assume its Enumerable. More logic can be built here if that's not true.
IEnumerable collection = (IEnumerable)p.GetValue(item);
foreach (var obj in collection)
{
db.Entry(obj).State = EntityState.Detached;
DetachAll(db, obj, recursionDepth - 1);
}
}
else
{
var obj = p.GetValue(item);
db.Entry(obj).State = EntityState.Detached;
DetachAll(db, obj, recursionDepth - 1);
}
}
}
var queryableOrders = context.GetQueryable(includes);
var order = context.GetQueryable(includes).FirstOrDefault(o => o.OrderNumber == myOrderNumber);
//you can provide includes inline if you just have a couple
var order = context.GetQueryable<Order>(o => o.Tenders, o => o.SalesItems).FirstOrDefault(o => o.OrderNumber == myOrderNumber);
//如果您只有一对，就可以提供includesinline
var order=context.GetQueryable（o=>o.Tenders，o=>o.SalesItems）；
/// <summary>
/// Recursively detaches item and sub-items from EF. Assumes that all sub-objects are properties (not fields).
/// </summary>
/// <param name="item">The item to detach</param>
/// <param name="recursionDepth">Number of levels to go before stopping. object.Property is 1, object.Property.SubProperty is 2, and so on.</param>
public static void DetachAll(this DbContext db, object item, int recursionDepth = 3)
{
//Exit if no remaining recursion depth
if (recursionDepth <= 0) return;
//detach this object
db.Entry(item).State = EntityState.Detached;
//get reflection data for all the properties we mean to detach
Type t = item.GetType();
var properties = t.GetProperties(BindingFlags.Public | BindingFlags.Instance)
.Where(p => p.GetSetMethod()?.IsPublic == true) //get only properties we can set
.Where(p => p.PropertyType.IsClass) //only classes can be EF objects
.Where(p => p.PropertyType != typeof(string)) //oh, strings. What a pain.
.Where(p => p.GetValue(item) != null); //only get set properties
//if we're recursing, we'll check here to make sure we should keep going
if (properties.Count() == 0) return;
foreach (var p in properties)
{
//handle generics
if (p.PropertyType.IsGenericType)
{
//assume its Enumerable. More logic can be built here if that's not true.
IEnumerable collection = (IEnumerable)p.GetValue(item);
foreach (var obj in collection)
{
db.Entry(obj).State = EntityState.Detached;
DetachAll(db, obj, recursionDepth - 1);
}
}
else
{
var obj = p.GetValue(item);
db.Entry(obj).State = EntityState.Detached;
DetachAll(db, obj, recursionDepth - 1);
}
}
}
var queryableOrders = context.GetQueryable(includes);
var order = context.GetQueryable(includes).FirstOrDefault(o => o.OrderNumber == myOrderNumber);
//you can provide includes inline if you just have a couple
var order = context.GetQueryable<Order>(o => o.Tenders, o => o.SalesItems).FirstOrDefault(o => o.OrderNumber == myOrderNumber);
//如果您只有一对，就可以提供includesinline
var order=context.GetQueryable（o=>o.Tenders，o=>o.SalesItems）；
entities db=new entities（）ALTER TABLE[dbo].[TABLE]WITH NOCHECK ADD CONSTRAINT[FK_TABLE_TABLE]外键（[ParentId]）引用[dbo].[TABLE]（[Id]）entities db=newentities（）ALTER TABLE[dbo].[TABLE]WITH NOCHECK ADD CONSTRAINT[FK_TABLE\u TABLE]外键（[ParentId]）引用[dbo].[TABLE]（[Id]）Person.Address.State.PersonPerson.Address.State.Person