I have update a generic update method as follows
public virtual void Update<TEntity>(TEntity entity, string modifiedBy =
null) where TEntity : class,IEntity
{
using (var context = new BanyanDbContext())
{
entity.ModifiedDate = DateTime.UtcNow;
entity.ModifiedBy = modifiedBy;
var existingEntiy = context.Set<TEntity>().Find(entity.Id);
context.Entry(existingEntiy).CurrentValues.SetValues(entity);
context.Entry(existingEntiy).State = EntityState.Modified;
Save(context);
}
}
This method is working fine for updating non reference type values, but CurrentValues.SetValues() does not set or update navigation properties.
How can I set navigation property in this scenario.
public TEntity RemoveNavigationProperties(TEntity input)
{
foreach (var item in input.GetType().GetProperties().Where(x => x.PropertyType.Namespace == input.GetType().Namespace))
{
item.SetValue(input, null);
}
return input;
}
This worked for me. (I just needed to null them)
As you can see below, I'm trying to update the "active" and "version" fields, which are properties of the templateData object.
When I want to add a new record, it works fine and meets the needs. But when I try to update the state.modified line, the error is:
Attaching an entity of type '...' failed because another entity already has the same primary key value. This can happen when using the 'Attach' method or setting the state of an entity to 'Unchanged' or 'Modified' if any entities in the graph have conflicting key values. This may be because some entities are new and have not received database-generated key values. In this case use the 'Add' method or the 'Added' entity state to track the graph and then set the state of non-new entities to 'Unchanged' or 'Modified' as appropriate.
Although I have tried many ways of crashing (as you noticed) I have not been successful.
What is the cause of this error? And how can I handle it?
Thank you for your help.
Service:
public ResultObject<TemplateData> SaveTemplateData(TemplateData oTemplateData)
{
var oResult = new ResultObject<TemplateData>();
using (var contextTransaction = _context.Database.BeginTransaction())
{
try
{
var listTempDatas = _context.TemplateDatas.Where(td => td.TemplateRID == oTemplateData.TemplateRID)
.ToList();
#region active/version
oTemplateData.Active = true;
if (listTempDatas.Count > 0)
{
#region resetActives
listTempDatas.ForEach(ltd => ltd.Active = false);
#endregion
#region getMaxVersion
var maxVersionValue = listTempDatas.Max(ltd => ltd.TemplateVersion);
//var maxVersionValue2 = listTempDatas.OrderByDescending(ltd => ltd.TemplateVersion).Select(ltd => ltd.TemplateVersion).First();
oTemplateData.TemplateVersion = maxVersionValue + 1;
#endregion
}
else if (listTempDatas.Count == 0)
{
oTemplateData.TemplateVersion = 1;
}
#endregion
if (oTemplateData.ID > 0)
{
var oldTempData = _context.TemplateDatas.AsNoTracking()
.FirstOrDefault(td => td.ID == oTemplateData.ID);
if (oldTempData != null)
_context.Entry(oTemplateData).State = EntityState.Modified;// and there it is
}
else if (oTemplateData.ID == 0)
{
_context.Entry(oTemplateData).State = EntityState.Added;
}
_context.SaveChanges();
oResult.ResulObject = oTemplateData;
contextTransaction.Commit();
}
catch (Exception e)
{
contextTransaction.Rollback();
oResult.AddError("TemplateService.SaveTemplateData", e.ToString());
}
}
return oResult;
}
Entity:
public class TemplateData
{
...
public int ID { get; set; }
public int? TemplateRID { get; set; }
...
public int? TemplateVersion { get; set; }
public bool? Active { get; set; }
...
public virtual Template Template { get; set; }
}
DataContextExtension:
public static ApplicationDbContext BulkInsert<T>(this ApplicationDbContext context, T entity, int count,
int batchSize) where T : class
{
context.Set<T>().Add(entity);
if (count % batchSize == 0)
{
context.SaveChanges();
context.Dispose();
context = new ApplicationDbContext();
// This is optional
context.Configuration.AutoDetectChangesEnabled = false;
}
return context;
}
The problem is that the line
var listTempDatas = _context.TemplateDatas.Where(td => td.TemplateRID == oTemplateData.TemplateRID)
.ToList();
already loads (tracks) in the context the existing entity you are trying to update.
So first you can try to find it in that list (instead of with a separate database query):
var oldTempData = listTempDatas.FirstOrDefault(td => td.ID == oTemplateData.ID);
and then simply update the properties of the existing entity rather than trying to mark the detached entity as modified:
if (oldTempData != null)
_context.Entry(oldTempData).CurrentValues.SetValues(oTemplateData); // and there you go
I have an entity which is not connected to my dbcontext. I want to change that. However there is already another instance of the same entity attached to dbcontext. If I just add my new entity, I get an error, that an entity with the same primary key is already attached.
I tried multiple different variants of removing the old entity from dbcontext without any success. How can I replace the old instance with the new one?
Note: I don't want to copy the values, I want to attach this very instance of my new entity to dbcontext.
var entity = new MyEntity { Id = 1 };
var logicalDuplicate = dbcontext.Set<MyEntity >().Local
.FirstOrDefault(e => e.Equals(entity));
if (logicalDuplicate != null)
{
// remove logicalDuplicate from dbcontext
}
dbcontext.MyEntity.Attach(entity);
For clarification: I have overridden Equals to check for Id instead of reference.
Try this:
if (logicalDuplicate != null)
{
dbcontext.Entry(logicalDuplicate).State = EntityState.Detached;
dbcontext.MyEntity.Attach(entity);
dbcontext.Entry(entity).State = EntityState.Modified;
}
else
{
dbcontext.MyEntity.Add(entity);
}
How to get related entries
I investigated that and want to share with my results.
I used reflection as short way to get entity properties names. But it's possible to get it without reflection as mentioned #Florian Haider. You can use
answer and this.
// Found loaded related entries that can be detached later.
private HashSet<DbEntityEntry> relatedEntries;
private DbContext context;
private List<string> GetPropertiesNames(object classObject)
{
// TODO Use cache for that.
// From question https://stackoverflow.com/questions/5851274/how-to-get-all-names-of-properties-in-an-entity
var properties = classObject.GetType().GetProperties(BindingFlags.DeclaredOnly |
BindingFlags.Public |
BindingFlags.Instance);
return properties.Select(t => t.Name).ToList();
}
private void GetRelatedEntriesStart(DbEntityEntry startEntry)
{
relatedEntries = new HashSet<DbEntityEntry>();
// To not process start entry twice.
relatedEntries.Add(startEntry);
GetRelatedEntries(startEntry);
}
private void GetRelatedEntries(DbEntityEntry entry)
{
IEnumerable<string> propertyNames = GetPropertiesNames(entry.Entity);
foreach (string propertyName in propertyNames)
{
DbMemberEntry dbMemberEntry = entry.Member(propertyName);
DbReferenceEntry dbReferenceEntry = dbMemberEntry as DbReferenceEntry;
if (dbReferenceEntry != null)
{
if (!dbReferenceEntry.IsLoaded)
{
continue;
}
DbEntityEntry refEntry = context.Entry(dbReferenceEntry.CurrentValue);
CheckReferenceEntry(refEntry);
}
else
{
DbCollectionEntry dbCollectionEntry = dbMemberEntry as DbCollectionEntry;
if (dbCollectionEntry != null && dbCollectionEntry.IsLoaded)
{
foreach (object entity in (ICollection)dbCollectionEntry.CurrentValue)
{
DbEntityEntry refEntry = context.Entry(entity);
CheckReferenceEntry(refEntry);
}
}
}
}
}
private void CheckReferenceEntry(DbEntityEntry refEntry)
{
// Add refEntry.State check here for your need.
if (!relatedEntries.Contains(refEntry))
{
relatedEntries.Add(refEntry);
GetRelatedEntries(refEntry);
}
}
Edit This finds the original product, removes it, and adds the new one:
static void UpdateDatabase()
{
Context context = new Context();
Product product1 = context.Products.Find(1);
context.Products.Remove(product1);
Product product2 = new Product(){ProductId = 1, Name = "Product2"};
context.Products.Add(product2);
context.SaveChanges();
}
Best way to salve this problem is
db is my database Object
updateprice is my database entity object
ep is my old same database entity object
db.Entry(updateprice).CurrentValues.SetValues(ep);
I am trying to override SaveChanges DbContect using Entity Framework.
The
override int SaveChanges()
is not running and the break-point is not being hit.
I have moved the class into the root where the EDMX file is located but that still did not help.
How can get I the SaveChanges override to work?
using System;
using System.Data.Entity;
namespace DAL
{
public class MyEntities : DbContext
{
public override int SaveChanges()
{
throw new Exception("override DbContext>SaveChanges working");
// return base.SaveChanges();
}
}
}
Code to call SaveChanges
using (var ctx = new Entities())
{
// model.clientID = data.clientID;
// model.clientGUID = data.clientGUID;
model.clientName = data.clientName;
model.clientDept = data.clientDept;
model.clientWebsite = data.clientWebsite;
model.clientEmail = data.clientEmail;
model.isActive = data.isActive;
model.clientModDate = data.clientModDate;
model.clientCreatedDate = data.clientCreatedDate;
ctx.Clients.Add(model);
ctx.SaveChanges();
}
The easiest way: the EF class is defined with "partial". So add another class file with the class name being:
public partial class MyEntities
{
public void SavingChanges()
{
//Do custom code
this.SaveChanges();
}
}
And change all of your SaveChanges() calls to SavingChanges(). Then you can customize the process however you want. The key is to add another partial class so make sure the EF context has the partial defined (not in your code sample but was the default implementation).
I was able to get the code working using the comments provided.
Create the class file in the same project the EDMX is located
public partial class Entities <--- same name as project Entity
all working now!
https://exceptionnotfound.net/entity-change-tracking-using-dbcontext-in-entity-framework-6/
namespace ModelApp_MVC.Models
{
public partial class Entities : DbContext
{
public override int SaveChanges()
{
//Do custom code
// throw new Exception("override DbContext>SaveChanges working");
// this.SaveChanges();
var modifiedEntities = ChangeTracker.Entries()
.Where(p => p.State == EntityState.Modified).ToList();
var now = DateTime.UtcNow;
foreach (var change in modifiedEntities)
{
var entityName = change.Entity.GetType().Name;
var primaryKey = GetPrimaryKeyValue(change);
foreach (var prop in change.OriginalValues.PropertyNames)
{
var originalValue = change.OriginalValues[prop].ToString();
var currentValue = change.CurrentValues[prop].ToString();
if (originalValue != currentValue) //Only create a log if the value changes
{
ChangeLog log = new ChangeLog()
{
EntityName = entityName,
PrimaryKeyValue = primaryKey.ToString(),
PropertyName = prop,
OldValue = originalValue,
NewValue = currentValue,
DateChanged = now
};
ChangeLogs.Add(log);
}
}
}
return base.SaveChanges();
}
object GetPrimaryKeyValue(DbEntityEntry entry)
{
var objectStateEntry = ((IObjectContextAdapter)this).ObjectContext.ObjectStateManager.GetObjectStateEntry(entry.Entity);
return objectStateEntry.EntityKey.EntityKeyValues[0].Value;
}
}
}
Frustrating, this. Here's a pair of related objects, as generated by database-first Entity Framework:
public partial class DevelopmentType
{
public DevelopmentType()
{
this.DefaultCharges = new HashSet<DefaultCharge>();
}
public System.Guid RowId { get; set; }
public string Type { get; set; }
public virtual ICollection<DefaultCharge> DefaultCharges { get; set; }
}
public partial class DefaultCharge
{
public System.Guid RowId { get; set; }
public decimal ChargeableRate { get; set; }
public Nullable<System.Guid> DevelopmentType_RowId { get; set; }
public virtual DevelopmentType DevelopmentType { get; set; }
}
Here's the code that I'm calling to save a DevelopmentType - it involves automapper since we differentiate entity objects from DTOs:
public void SaveDevelopmentType(DevelopmentType_dto dt)
{
Entities.DevelopmentType mappedDevType = Mapper.Map<DevelopmentType_dto, Entities.DevelopmentType>(dt);
_Context.Entry(mappedDevType).State = System.Data.EntityState.Modified;
_Context.DevelopmentTypes.Attach(mappedDevType);
_Context.SaveChanges();
}
In my user interface, the most common operation will be for a user to look at a list of DevelopmentTypes and update their DefaultCharge. So when I test this using the above code, it runs without error, but nothing actually changes.
If I pause in the debugger it's clear that the changed DefaultCharge is being passed into the function, and that it's attached to the DevelopmentType to be saved.
Stepping through it, if I change the value manually inside visual studio, it does save the updated value. Which is just even more confusing.
Monitoring the database with SQL Server Profiler reveals that update commands are issued only for the parent object and not for any attached objects.
I have other similar code elsewhere that functions as expected. What am I doing wrong here?
EDIT:
I have discovered that if you do this prior to the call to SaveDevelopmentType:
using (TransactionScope scope = new TransactionScope())
{
dt.Type = "Test1";
dt.DefaultCharges.First().ChargeableRate = 99;
_CILRepository.SaveDevelopmentType(dt);
scope.Complete();
}
The change to Type saves, but the change to ChargeableRate does not. I don't think it helps, massively, but thought I'd add it.
The problem is, that EF is not aware of the changed DefaultCharges.
By setting the State of the DevelopmentType to EntityState.Modified, EF only knows that the object DevelopmentType has been changed. However, this means that EF will only update DevelopmentType but not it's navigation properties.
A workaround - which isn't best practice - would be to iterate over all DefaultCharge of the current DevelopmentType and set the entity state to EntityState.Modified.
Additionally I would recommend to attach the entity to the context first, and change the state afterwards.
EDIT after comment
As you are using DTOs I suppose you are transfering these objects either through different layers or different machines.
In this case I would recommend to use self tracking entities, because it is not possible to share one context. These entities additionally holds their current state (ie. new, updated, deleted etc). There are many tutorials on the net about self tracking entities.
e.g. MSDN - Working with Self-Tracking Entities
As far as I know EF can save child entities only if the parent object was retrieved with the same Context that is trying to save it. That is attaching an object that was retrieved by one context to another context, will allow you to save changes to parent objects but not children. This was the result of a on old search based on which we switched to NHibernate. If memory serves correctly I was able to find a link where EF team member(s) confirmed this and that there WAS no plan to change this behavior. Unfortunately all links related to that search have been erased from my PC since.
As I am not aware of how you are retrieving the objects in your case, I am not sure this is relevant to your case, but put it out there just in case it helps.
Here is a link on attaching detached objects to a context.
http://www.codeproject.com/Articles/576330/Attaching-detached-POCO-to-EF-DbContext-simple-and
Context.Entry() already "Attaches" the Entity internally in order to have the context change its EntityState.
By calling Attach() you're changing the EntityState back to Unchanged. Try to comment out this line.
The Graphdiff library was a great help for me to handle all of these complexities.
You only need to set up the navigation properties that you wish to insert/update/delete (using fluent syntax) and Graphdiff will take care of it
Note: It seems to be that the project is not updated anymore but i'm using it since more than a year and is quite stable
This is not a workaround for every case, but I did discover that you can get around this by updating foreign keys on an object instead of updating navigation property objects.
For example... instead of:
myObject.myProperty = anotherPropertyObject;
Try this:
myObject.myPropertyID = anotherPropertyObject.ID;
Make sure the object is flagged as modified in EF's mind (as mentioned in other posts) and then call your save method.
Worked for me at least! It'll be a no-go when working with nested properties, but perhaps you can break your contexts up into smaller chunks and work over objects in multiple parts to avoid context bloat.
Good luck! :)
If I understand the question correctly, you have problem updating child fields. I had problems with child collection fields. I tried this and it worked for me.
You should update all child collections after attaching the object to the database context change the modified state of the parent object and save changes to the context.
Database.Products.Attach(argProduct);
argProduct.Categories = Database.Categories.Where(x => ListCategories.Contains(x.CategoryId)).ToList();
Database.Entry(argProduct).State = EntityState.Modified;
Database.SaveChanges();
I created a helper method to solve this problem.
Consider this:
public abstract class BaseEntity
{
/// <summary>
/// The unique identifier for this BaseEntity.
/// </summary>
[Key]
public Guid Id { get; set; }
}
public class BaseEntityComparer : IEqualityComparer<BaseEntity>
{
public bool Equals(BaseEntity left, BaseEntity right)
{
if (ReferenceEquals(null, right)) { return false; }
return ReferenceEquals(left, right) || left.Id.Equals(right.Id);
}
public int GetHashCode(BaseEntity obj)
{
return obj.Id.GetHashCode();
}
}
public class Event : BaseEntity
{
[Required(AllowEmptyStrings = false)]
[StringLength(256)]
public string Name { get; set; }
public HashSet<Manager> Managers { get; set; }
}
public class Manager : BaseEntity
{
[Required(AllowEmptyStrings = false)]
[StringLength(256)]
public string Name { get; set; }
public Event Event{ get; set; }
}
DbContext with the helper method:
public class MyDataContext : DbContext
{
public MyDataContext() : base("ConnectionName") { }
//Tables
public DbSet<Event> Events { get; set; }
public DbSet<Manager> Managers { get; set; }
public async Task AddOrUpdate<T>(T entity, params string[] ignoreProperties) where T : BaseEntity
{
if (entity == null || Entry(entity).State == EntityState.Added || Entry(entity).State == EntityState.Modified) { return; }
var state = await Set<T>().AnyAsync(x => x.Id == entity.Id) ? EntityState.Modified : EntityState.Added;
Entry(entity).State = state;
var type = typeof(T);
RelationshipManager relationship;
var stateManager = ((IObjectContextAdapter)this).ObjectContext.ObjectStateManager;
if (stateManager.TryGetRelationshipManager(entity, out relationship))
{
foreach (var end in relationship.GetAllRelatedEnds())
{
var isForeignKey = end.GetType().GetProperty("IsForeignKey", BindingFlags.Instance | BindingFlags.NonPublic)?.GetValue(end) as bool?;
var navigationProperty = end.GetType().GetProperty("NavigationProperty", BindingFlags.Instance | BindingFlags.NonPublic)?.GetValue(end);
var propertyName = navigationProperty?.GetType().GetProperty("Identity", BindingFlags.Instance | BindingFlags.NonPublic)?.GetValue(navigationProperty) as string;
if (string.IsNullOrWhiteSpace(propertyName) || ignoreProperties.Contains(propertyName)) { continue; }
var property = type.GetProperty(propertyName);
if (property == null) { continue; }
if (end is IEnumerable) { await UpdateChildrenInternal(entity, property, isForeignKey == true); }
else { await AddOrUpdateInternal(entity, property, ignoreProperties); }
}
}
if (state == EntityState.Modified)
{
Entry(entity).OriginalValues.SetValues(await Entry(entity).GetDatabaseValuesAsync());
Entry(entity).State = GetChangedProperties(Entry(entity)).Any() ? state : EntityState.Unchanged;
}
}
private async Task AddOrUpdateInternal<T>(T entity, PropertyInfo property, params string[] ignoreProperties)
{
var method = typeof(EasementDataContext).GetMethod("AddOrUpdate");
var generic = method.MakeGenericMethod(property.PropertyType);
await (Task)generic.Invoke(this, new[] { property.GetValue(entity), ignoreProperties });
}
private async Task UpdateChildrenInternal<T>(T entity, PropertyInfo property, bool isForeignKey)
{
var type = typeof(T);
var method = isForeignKey ? typeof(EasementDataContext).GetMethod("UpdateForeignChildren") : typeof(EasementDataContext).GetMethod("UpdateChildren");
var objType = property.PropertyType.GetGenericArguments()[0];
var enumerable = typeof(IEnumerable<>).MakeGenericType(objType);
var param = Expression.Parameter(type, "x");
var body = Expression.Property(param, property);
var lambda = Expression.Lambda(Expression.Convert(body, enumerable), property.Name, new[] { param });
var generic = method.MakeGenericMethod(type, objType);
await (Task)generic.Invoke(this, new object[] { entity, lambda, null });
}
public async Task UpdateForeignChildren<T, TProperty>(T parent, Expression<Func<T, IEnumerable<TProperty>>> childSelector, IEqualityComparer<TProperty> comparer = null) where T : BaseEntity where TProperty : BaseEntity
{
var children = (childSelector.Invoke(parent) ?? Enumerable.Empty<TProperty>()).ToList();
foreach (var child in children) { await AddOrUpdate(child); }
var existingChildren = await Set<T>().Where(x => x.Id == parent.Id).SelectMany(childSelector).AsNoTracking().ToListAsync();
if (comparer == null) { comparer = new BaseEntityComparer(); }
foreach (var child in existingChildren.Except(children, comparer)) { Entry(child).State = EntityState.Deleted; }
}
public async Task UpdateChildren<T, TProperty>(T parent, Expression<Func<T, IEnumerable<TProperty>>> childSelector, IEqualityComparer<TProperty> comparer = null) where T : BaseEntity where TProperty : BaseEntity
{
var stateManager = ((IObjectContextAdapter)this).ObjectContext.ObjectStateManager;
var currentChildren = childSelector.Invoke(parent) ?? Enumerable.Empty<TProperty>();
var existingChildren = await Set<T>().Where(x => x.Id == parent.Id).SelectMany(childSelector).AsNoTracking().ToListAsync();
if (comparer == null) { comparer = new BaseEntityComparer(); }
var addedChildren = currentChildren.Except(existingChildren, comparer).AsEnumerable();
var deletedChildren = existingChildren.Except(currentChildren, comparer).AsEnumerable();
foreach (var child in currentChildren) { await AddOrUpdate(child); }
foreach (var child in addedChildren) { stateManager.ChangeRelationshipState(parent, child, childSelector.Name, EntityState.Added); }
foreach (var child in deletedChildren)
{
Entry(child).State = EntityState.Unchanged;
stateManager.ChangeRelationshipState(parent, child, childSelector.Name, EntityState.Deleted);
}
}
public static IEnumerable<string> GetChangedProperties(DbEntityEntry dbEntry)
{
var propertyNames = dbEntry.State == EntityState.Added ? dbEntry.CurrentValues.PropertyNames : dbEntry.OriginalValues.PropertyNames;
foreach (var propertyName in propertyNames)
{
if (IsValueChanged(dbEntry, propertyName))
{
yield return propertyName;
}
}
}
private static bool IsValueChanged(DbEntityEntry dbEntry, string propertyName)
{
return !Equals(OriginalValue(dbEntry, propertyName), CurrentValue(dbEntry, propertyName));
}
private static string OriginalValue(DbEntityEntry dbEntry, string propertyName)
{
string originalValue = null;
if (dbEntry.State == EntityState.Modified)
{
originalValue = dbEntry.OriginalValues.GetValue<object>(propertyName) == null
? null
: dbEntry.OriginalValues.GetValue<object>(propertyName).ToString();
}
return originalValue;
}
private static string CurrentValue(DbEntityEntry dbEntry, string propertyName)
{
string newValue;
try
{
newValue = dbEntry.CurrentValues.GetValue<object>(propertyName) == null
? null
: dbEntry.CurrentValues.GetValue<object>(propertyName).ToString();
}
catch (InvalidOperationException) // It will be invalid operation when its in deleted state. in that case, new value should be null
{
newValue = null;
}
return newValue;
}
}
Then I call it like this
// POST: Admin/Events/Edit/5
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Edit(Event #event)
{
if (!ModelState.IsValid) { return View(#event); }
await _db.AddOrUpdate(#event);
await _db.SaveChangesAsync();
return RedirectToAction("Index");
}