C# 在EF中更新父实体时如何添加/更新子实体
这两个实体是一对多关系（由CodeFirstFluentAPI构建） 目前我有两个想法：C# 在EF中更新父实体时如何添加/更新子实体,c#,asp.net-mvc,entity-framework,asp.net-web-api,C#,Asp.net Mvc,Entity Framework,Asp.net Web Api,这两个实体是一对多关系（由CodeFirstFluentAPI构建） 目前我有两个想法： 通过model.Id获取名为existing的跟踪父实体，并将model中的值逐个分配给该实体。这听起来很愚蠢。在model.Children中，我不知道哪个孩子是新的，哪个孩子被修改（甚至被删除） 通过模型创建新的父实体，并将其附加到DbContext并保存。但是DbContext如何知道子级的状态（新增/删除/修改） 实现此功能的正确方法是什么？因为发布到WebApi控制器的模型与任何实体框架（EF）上
model.Idexistingmodelmodel.Children模型实现此功能的正确方法是什么？因为发布到WebApi控制器的模型与任何实体框架（EF）上下文分离，所以唯一的选择是从数据库加载对象图（父对象包括其子对象），并比较添加、删除或更新的子对象。（除非您在分离状态（在浏览器中或任何地方）期间使用自己的跟踪机制跟踪更改，我认为这比以下情况更复杂。）它可能如下所示：
public void Update(UpdateParentModel model)
{
var existingParent = _dbContext.Parents
.Where(p => p.Id == model.Id)
.Include(p => p.Children)
.SingleOrDefault();
if (existingParent != null)
{
// Update parent
_dbContext.Entry(existingParent).CurrentValues.SetValues(model);
// Delete children
foreach (var existingChild in existingParent.Children.ToList())
{
if (!model.Children.Any(c => c.Id == existingChild.Id))
_dbContext.Children.Remove(existingChild);
}
// Update and Insert children
foreach (var childModel in model.Children)
{
var existingChild = existingParent.Children
.Where(c => c.Id == childModel.Id && c.Id != default(int))
.SingleOrDefault();
if (existingChild != null)
// Update child
_dbContext.Entry(existingChild).CurrentValues.SetValues(childModel);
else
{
// Insert child
var newChild = new Child
{
Data = childModel.Data,
//...
};
existingParent.Children.Add(newChild);
}
}
_dbContext.SaveChanges();
}
}
…CurrentValues.SetValuesprotected void UpdateChildCollection<Tparent, Tid , Tchild>(Tparent dbItem, Tparent newItem, Func<Tparent, IEnumerable<Tchild>> selector, Func<Tchild, Tid> idSelector) where Tchild : class
{
var dbItems = selector(dbItem).ToList();
var newItems = selector(newItem).ToList();
if (dbItems == null && newItems == null)
return;
var original = dbItems?.ToDictionary(idSelector) ?? new Dictionary<Tid, Tchild>();
var updated = newItems?.ToDictionary(idSelector) ?? new Dictionary<Tid, Tchild>();
var toRemove = original.Where(i => !updated.ContainsKey(i.Key)).ToArray();
var removed = toRemove.Select(i => DbContext.Entry(i.Value).State = EntityState.Deleted).ToArray();
var toUpdate = original.Where(i => updated.ContainsKey(i.Key)).ToList();
toUpdate.ForEach(i => DbContext.Entry(i.Value).CurrentValues.SetValues(updated[i.Key]));
var toAdd = updated.Where(i => !original.ContainsKey(i.Key)).ToList();
toAdd.ForEach(i => DbContext.Set<Tchild>().Add(i.Value));
}
不知道这一切将如何在规模上执行，但不确定如何处理此问题。只是概念验证
控制器。UpdateModelconst string PK=“Id”；
受保护的模型；
受保护的System.Data.Entity.DbSet模型；
私有void TestUpdate（对象项）
{
var props=item.GetType（）.GetProperties（）；
foreach（道具中的var道具）
{
对象值=道具获取值（项目）；
if（prop.PropertyType.IsInterface&&value！=null）
{
foreach（变量iItem in（System.Collections.IEnumerable）值）
{
测试更新（iItem）；
}
}
}
int id=（int）item.GetType（）.GetProperty（PK）.GetValue（item）；
如果（id==0）
{
con.Entry（item）.State=System.Data.Entity.EntityState.Added；
}
其他的
{
con.Entry（item）.State=System.Data.Entity.EntityState.Modified；
}
}
上述两个项目都在断开连接的实体返回到服务器时识别这些实体，检测并保存更改，并返回到受客户端影响的数据。如果使用EntityFrameworkCore，则可以在控制器post操作中执行以下操作（递归附加导航属性，包括集合）：
\u context.Attach（modelPostedToController）；
IEnumerable unchangedEntities=_context.ChangeTracker.Entries（）。其中（x=>x.State==EntityState.Unchanged）；
foreach（实体进入未更改的ee）{
ee.State=EntityState.Modified；
}
wait_context.SaveChangesAsync（）；
您还需要确保为此操作使用了新的/专用的实体框架数据库上下文。好的。我曾经有过这样的答案，但一路上都忘了。当你知道有更好的方法但却记不住或找不到时，绝对是折磨！这很简单。我只是用多种方法测试了它
var parent = _dbContext.Parents
.Where(p => p.Id == model.Id)
.Include(p => p.Children)
.FirstOrDefault();
parent.Children = _dbContext.Children.Where(c => <Query for New List Here>);
_dbContext.Entry(parent).State = EntityState.Modified;
_dbContext.SaveChanges();
var parent=\u dbContext.Parents
.Where（p=>p.Id==model.Id）
.包括（p=>p.儿童）
.FirstOrDefault（）；
parent.Children=_dbContext.Children.Where（c=>）；
_dbContext.Entry（parent.State=EntityState.Modified；
_dbContext.SaveChanges（）；
您可以用新列表替换整个列表！SQL代码将根据需要删除和添加实体。你不必担心那件事。一定要包括儿童收集或没有骰子。祝你好运 @查尔斯·麦金托什（Charles McIntosh）确实为我的情况给出了答案，因为传入的模型是分离的。对我来说，最终起作用的是首先保存传入的模型。。。然后继续添加子项，就像我以前一样：
public async Task<IHttpActionResult> GetUPSFreight(PartsExpressOrder order)
{
db.Entry(order).State = EntityState.Modified;
db.SaveChanges();
...
}
公共异步任务GetUpsCargo（PartsExpressOrder）
{
db.Entry（order）.State=EntityState.Modified；
db.SaveChanges（）；
...
}
公共异步任务PutParent（int-id，Parent-Parent）
{
如果（！ModelState.IsValid）
{
返回请求（ModelState）；
}
if（id！=parent.id）
{
返回请求（）；
}
db.Entry（parent.State=EntityState.Modified；
foreach（parent.Children中的子项）
{
db.Entry（child.State=child.Id==0？EntityState.Added:EntityState.Modified；
}
尝试
{
等待db.saveChangesSync（）；
}
catch（DbUpdateConcurrencyException）
{
如果（！ParentExists（id））
{
返回NotFound（）；
}
其他的
{
投掷；
}
UpdateChildCollection(dbCopy, detached, p => p.MyCollectionProp, collectionItem => collectionItem.Id)
const string PK = "Id";
protected Models.Entities con;
protected System.Data.Entity.DbSet<T> model;
private void TestUpdate(object item)
{
var props = item.GetType().GetProperties();
foreach (var prop in props)
{
object value = prop.GetValue(item);
if (prop.PropertyType.IsInterface && value != null)
{
foreach (var iItem in (System.Collections.IEnumerable)value)
{
TestUpdate(iItem);
}
}
}
int id = (int)item.GetType().GetProperty(PK).GetValue(item);
if (id == 0)
{
con.Entry(item).State = System.Data.Entity.EntityState.Added;
}
else
{
con.Entry(item).State = System.Data.Entity.EntityState.Modified;
}
}
_context.Attach(modelPostedToController);
IEnumerable<EntityEntry> unchangedEntities = _context.ChangeTracker.Entries().Where(x => x.State == EntityState.Unchanged);
foreach(EntityEntry ee in unchangedEntities){
ee.State = EntityState.Modified;
}
await _context.SaveChangesAsync();
var parent = _dbContext.Parents
.Where(p => p.Id == model.Id)
.Include(p => p.Children)
.FirstOrDefault();
parent.Children = _dbContext.Children.Where(c => <Query for New List Here>);
_dbContext.Entry(parent).State = EntityState.Modified;
_dbContext.SaveChanges();
public async Task<IHttpActionResult> GetUPSFreight(PartsExpressOrder order)
{
db.Entry(order).State = EntityState.Modified;
db.SaveChanges();
...
}
public async Task<IHttpActionResult> PutParent(int id, Parent parent)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (id != parent.Id)
{
return BadRequest();
}
db.Entry(parent).State = EntityState.Modified;
foreach (Child child in parent.Children)
{
db.Entry(child).State = child.Id == 0 ? EntityState.Added : EntityState.Modified;
}
try
{
await db.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!ParentExists(id))
{
return NotFound();
}
else
{
throw;
}
}
return Ok(db.Parents.Find(id));
}
updatechild(objCas.ECC_Decision, PromatCon.ECC_Decision.Where(Function(c) c.rid = objCas.rid And Not objCas.ECC_Decision.Select(Function(x) x.dcid).Contains(c.dcid)).toList)
Sub updatechild(Of Ety)(amList As ICollection(Of Ety), rList As ICollection(Of Ety))
If amList IsNot Nothing Then
For Each obj In amList
Dim x = PromatCon.Entry(obj).GetDatabaseValues()
If x Is Nothing Then
PromatCon.Entry(obj).State = EntityState.Added
Else
PromatCon.Entry(obj).State = EntityState.Modified
End If
Next
End If
If rList IsNot Nothing Then
For Each obj In rList.ToList
PromatCon.Entry(obj).State = EntityState.Deleted
Next
End If
End Sub
PromatCon.SaveChanges()
var parent = context.Parent.FirstOrDefault(x => x.Id == modelParent.Id);
if (parent != null)
{
parent.Childs = modelParent.Childs;
}
public async Task<bool> UpdateDeviceShutdownAsync(Guid id, DateTime shutdownAtTime, int areaID, decimal mileage,
decimal motohours, int driverID, List<int> commission,
string shutdownPlaceDescr, int deviceShutdownTypeID, string deviceShutdownDesc,
bool isTransportation, string violationConditions, DateTime shutdownStartTime,
DateTime shutdownEndTime, string notes, List<Guid> faultIDs )
{
try
{
using (var db = new GJobEntities())
{
var isExisting = await db.DeviceShutdowns.FirstOrDefaultAsync(x => x.ID == id);
if (isExisting != null)
{
isExisting.AreaID = areaID;
isExisting.DriverID = driverID;
isExisting.IsTransportation = isTransportation;
isExisting.Mileage = mileage;
isExisting.Motohours = motohours;
isExisting.Notes = notes;
isExisting.DeviceShutdownDesc = deviceShutdownDesc;
isExisting.DeviceShutdownTypeID = deviceShutdownTypeID;
isExisting.ShutdownAtTime = shutdownAtTime;
isExisting.ShutdownEndTime = shutdownEndTime;
isExisting.ShutdownStartTime = shutdownStartTime;
isExisting.ShutdownPlaceDescr = shutdownPlaceDescr;
isExisting.ViolationConditions = violationConditions;
// Delete children
foreach (var existingChild in isExisting.DeviceShutdownFaults.ToList())
{
db.DeviceShutdownFaults.Remove(existingChild);
}
if (faultIDs != null && faultIDs.Any())
{
foreach (var faultItem in faultIDs)
{
var newChild = new DeviceShutdownFault
{
ID = Guid.NewGuid(),
DDFaultID = faultItem,
DeviceShutdownID = isExisting.ID,
};
isExisting.DeviceShutdownFaults.Add(newChild);
}
}
// Delete all children
foreach (var existingChild in isExisting.DeviceShutdownComissions.ToList())
{
db.DeviceShutdownComissions.Remove(existingChild);
}
// Add all new children
if (commission != null && commission.Any())
{
foreach (var cItem in commission)
{
var newChild = new DeviceShutdownComission
{
ID = Guid.NewGuid(),
PersonalID = cItem,
DeviceShutdownID = isExisting.ID,
};
isExisting.DeviceShutdownComissions.Add(newChild);
}
}
await db.SaveChangesAsync();
return true;
}
}
}
catch (Exception ex)
{
logger.Error(ex);
}
return false;
}
public async Task UpdateAsync(TempOrder order)
{
order.CheckNotNull(nameof(order));
order.OrderId.CheckNotNull(nameof(order.OrderId));
order.DateModified = _dateService.UtcNow;
if (_context.Entry(order).State == EntityState.Modified)
{
await _context.SaveChangesAsync().ConfigureAwait(false);
}
else // Detached.
{
var existing = await SelectAsync(order.OrderId!.Value).ConfigureAwait(false);
if (existing != null)
{
order.DateModified = _dateService.UtcNow;
_context.TrackChildChanges(order.Products, existing.Products, (a, b) => a.OrderProductId == b.OrderProductId);
await _context.SaveChangesAsync(order, existing).ConfigureAwait(false);
}
}
}
/// <summary>
/// Tracks changes on childs models by comparing with latest database state.
/// </summary>
/// <typeparam name="T">The type of model to track.</typeparam>
/// <param name="context">The database context tracking changes.</param>
/// <param name="childs">The childs to update, detached from the context.</param>
/// <param name="existingChilds">The latest existing data, attached to the context.</param>
/// <param name="match">A function to match models by their primary key(s).</param>
public static void TrackChildChanges<T>(this DbContext context, IList<T> childs, IList<T> existingChilds, Func<T, T, bool> match)
where T : class
{
context.CheckNotNull(nameof(context));
childs.CheckNotNull(nameof(childs));
existingChilds.CheckNotNull(nameof(existingChilds));
// Delete childs.
foreach (var existing in existingChilds.ToList())
{
if (!childs.Any(c => match(c, existing)))
{
existingChilds.Remove(existing);
}
}
// Update and Insert childs.
var existingChildsCopy = existingChilds.ToList();
foreach (var item in childs.ToList())
{
var existing = existingChildsCopy
.Where(c => match(c, item))
.SingleOrDefault();
if (existing != null)
{
// Update child.
context.Entry(existing).CurrentValues.SetValues(item);
}
else
{
// Insert child.
existingChilds.Add(item);
// context.Entry(item).State = EntityState.Added;
}
}
}
/// <summary>
/// Saves changes to a detached model by comparing it with the latest data.
/// </summary>
/// <typeparam name="T">The type of model to save.</typeparam>
/// <param name="context">The database context tracking changes.</param>
/// <param name="model">The model object to save.</param>
/// <param name="existing">The latest model data.</param>
public static void SaveChanges<T>(this DbContext context, T model, T existing)
where T : class
{
context.CheckNotNull(nameof(context));
model.CheckNotNull(nameof(context));
context.Entry(existing).CurrentValues.SetValues(model);
context.SaveChanges();
}
/// <summary>
/// Saves changes to a detached model by comparing it with the latest data.
/// </summary>
/// <typeparam name="T">The type of model to save.</typeparam>
/// <param name="context">The database context tracking changes.</param>
/// <param name="model">The model object to save.</param>
/// <param name="existing">The latest model data.</param>
/// <param name="cancellationToken">A cancellation token to cancel the operation.</param>
/// <returns></returns>
public static async Task SaveChangesAsync<T>(this DbContext context, T model, T existing, CancellationToken cancellationToken = default)
where T : class
{
context.CheckNotNull(nameof(context));
model.CheckNotNull(nameof(context));
context.Entry(existing).CurrentValues.SetValues(model);
await context.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
}
{
"groupId": 1,
"groupName": "Group 1",
"sortOrder": 1,
"filterNames": [
{
"filterId": 1,
"filterName1": "Name11111",
"sortOrder": 10,
"groupId": 1
} ,
{
"filterId": 1006,
"filterName1": "Name Changed 1",
"sortOrder": 10,
"groupId": 1
} ,
{
"filterId": 1007,
"filterName1": "New Filter 1",
"sortOrder": 10,
"groupId": 1
} ,
{
"filterId": 2,
"filterName1": "Name 2 Changed",
"sortOrder": 10,
"groupId": 1
}
]
}
public async Task<int> UpdateFilter(FilterGroup filterGroup)
{
var Ids = from f in filterGroup.FilterNames select f.FilterId;
var toBeDeleted = dbContext.FilterNames.Where(x => x.GroupId == filterGroup.GroupId
&& !Ids.Contains(x.FilterId)).ToList();
foreach(var item in toBeDeleted)
{
dbContext.FilterNames.Remove(item);
}
await dbContext.SaveChangesAsync();
dbContext.FilterGroups.Attach(filterGroup);
dbContext.Entry(filterGroup).State = EntityState.Modified;
for(int i=0;i<filterGroup.FilterNames.Count();i++)
{
if (filterGroup.FilterNames.ElementAt(i).FilterId != 0)
{
dbContext.Entry(filterGroup.FilterNames.ElementAt(i)).State = EntityState.Modified;
}
}
return await dbContext.SaveChangesAsync();
}
private void Reconcile<T>(DbContext context,
IReadOnlyCollection<T> oldItems,
IReadOnlyCollection<T> newItems,
Func<T, T, bool> compare)
{
var itemsToAdd = new List<T>();
var itemsToRemove = new List<T>();
foreach (T newItem in newItems)
{
T oldItem = oldItems.FirstOrDefault(arg1 => compare(arg1, newItem));
if (oldItem == null)
{
itemsToAdd.Add(newItem);
}
else
{
context.Entry(oldItem).CurrentValues.SetValues(newItem);
}
}
foreach (T oldItem in oldItems)
{
if (!newItems.Any(arg1 => compare(arg1, oldItem)))
{
itemsToRemove.Add(oldItem);
}
}
foreach (T item in itemsToAdd)
context.Add(item);
foreach (T item in itemsToRemove)
context.Remove(item);
}