Model OnDelete event? - entity-framework

I've got a simple model that looks like this:
public class ImageFile
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public ImageMeta Meta { get; set; }
public string FileName { get; set; }
public DateTime DateUploaded { get; set; }
public int Width { get; set; }
public int Height { get; set; }
}
Is there any way I can add some kind of "OnDelete" event hook so that whenever a model is deleted via db.Images.Remove(imageFile); or whatever other means, I can delete the associated file?

You can override the SaveChanges method of your context to hook up to delete entities.
public class GalleryContext : DbContext
{
public override int SaveChanges()
{
var deletedImages = ChangeTracker.Entries()
.Where(e => e.State == EntityState.Deleted && e.Entity is ImageFile)
.Select(e => e.Entity).Cast<ImageFile>();
foreach(var image in deletedImages)
{
// delete file here or call a method on image
}
return base.SaveChanges();
}
}

Related

One to Optional One Relation not updating the Principal Entity on EF Core

I Run into this scenario. I have related entities: Case and a Confinement
A Case has an optional navigation to confinement - ConfinementId, while the confinement has a required CaseId.
My problem is when I try to update the Case, by attaching the Confinement Record, the confinementID on the case entity is not updated.
Here are my mapping and Entity Classes:
public class Confinement : Entity
{
public int Id { get; set; }
public string ReferenceId { get; set; }
public int CaseId { get; set; }
public DateTime StartDate { get; set; }
public DateTime? EndDate { get; set; }
public bool IsActive { get; set; }
public int BranchId { get; set; }
public string Status { get; set; }
public virtual Case Case {get;set;}
}
public class Case : Entity
{
public int CaseId { get; set; }
public string CaseReferenceId { get; set; }
public int? ConsultationId { get; set; }
public int? ConfinementId { get; set; }
public virtual Confinement Confinement { get; set; }
****Omitted
}
Configuration
public void Configure(EntityTypeBuilder<Case> builder)
{
builder.HasKey(c => c.CaseId);
builder.HasMany(t => t.Details)
.WithOne(t => t.Case)
.HasForeignKey(t => t.CaseId);
builder.HasOne(t => t.Confinement)
.WithOne(a=>a.Case)
.HasForeignKey<Confinement>(t => t.CaseId);
}
public void Configure(EntityTypeBuilder<Confinement> builder)
{
builder.HasKey(c => c.Id);
builder.HasOne(a => a.Case)
.WithOne(a => a.Confinement)
.HasForeignKey<Confinement>(a => a.CaseId);
}
Controller Code
public async Task<IActionResult> AddConfinement(int caseId)
{
if (caseId == 0)
return BadRequest();
if (_service.ExistingCase(caseId))
return BadRequest("Case has already a confinement record!");
var #case = await _caseService.FindAsync(caseId);
if (#case == null)
return NotFound("Case not found!");
var confinement = _converter.ConvertFromCase(#case);
confinement.ObjectState = ObjectState.Added;
#case.Confinement = confinement;
#case.ObjectState = ObjectState.Modified;
#case.ConfinementId = confinement.Id;
_caseService.Update(#case);
await _unitOfWork.SaveChangesAsync();
return Ok();
}
When the AddConfinement Method is called, the confinement is added on the database, but the Case.ConfinementId is not updated. Is there anything wrong to this implementation.
As a workaround, I created a trigger on the database but i want to accomplish this on the application level.

Entity Framework circular dependency for last entity

Please consider the following entities
public class What {
public int Id { get; set; }
public string Name { get; set; }
public ICollection<Track> Tracks { get; set; }
public int? LastTrackId { get; set; }]
public Track LastTrack { get; set; }
}
public class Track {
public Track(string what, DateTime dt, TrackThatGeoposition pos) {
What = new What { Name = what, LastTrack = this };
}
public int Id { get; set; }
public int WhatId { get; set; }
public What What { get; set; }
}
I use the following to configure the entities:
builder.HasKey(x => x.Id);
builder.HasMany(x => x.Tracks).
WithOne(y => y.What).HasForeignKey(y => y.WhatId);
builder.Property(x => x.Name).HasMaxLength(100);
builder.HasOne(x => x.LastTrack).
WithMany().HasForeignKey(x => x.LastTrackId);
Has you can see there is a wanted circular reference:
What.LastTrack <-> Track.What
when I try to add a Track to the context (on SaveChanges in fact):
Track t = new Track("truc", Datetime.Now, pos);
ctx.Tracks.Add(t);
ctx.SaveChanges();
I get the following error:
Unable to save changes because a circular dependency was detected in the data to be saved: ''What' {'LastTrackId'} -> 'Track' {'Id'}, 'Track' {'WhatId'} -> 'What' {'Id'}'.
I would like to say... yes, I know but...
Is such a configuration doable with EF Core ?
This is what I like to call the favored child problem: a parent has multiple children, but one of them is extra special. This causes problems in real life... and in data processing.
In your class model, What (is that a sensible name, by the way?) has Tracks as children, but one of these, LastTrack is the special child to which What keeps a reference.
When both What and Tracks are created in one transaction, EF will try to use the generated What.Id to insert the new Tracks with WhatId. But before it can save What it needs the generated Id of the last Track. Since SQL databases can't insert records simultaneously, this circular reference can't be established in one isolated transaction.
You need one transaction to save What and its Tracks and a subsequent transaction to set What.LastTrackId.
To do this in one database transaction you can wrap the code in a TransactionScope:
using(var ts = new TransactionScope())
{
// do the stuff
ts.Complete();
}
If an exception occurs, ts.Complete(); won't happen and a rollback will occur when the TransactionScope is disposed.
I encountered the same problem, but i solved it differently.
In my case, it was about a list of status and a reference to the last status. So with the following case :
public class What {
public int Id { get; set; }
public string Name { get; set; }
public ICollection<Status> StatusList { get; set; }
public int? LastStatusId { get; set; }
public Status LastStatus { get; set; }
public void AddStatus(Status s)
{
StatusList.Add(s);
LastStatus = s;
}
}
public class Status{
public int Id { get; set; }
public int WhatId { get; set; }
public What What { get; set; }
}
In my program, i changed my code to use StatusList as an history that doesn't include the lastStatus, so :
public class What {
public int Id { get; set; }
public string Name { get; set; }
public ICollection<Status> StatusHistory { get; set; }
public int? LastStatusId { get; set; }
public Status LastStatus { get; set; }
public void AddStatus(Status s)
{
if(LastStatus) StatusList.Add(LastStatus);
LastStatus = s;
}
public List<Status> GetStatusList(Status s) // If needed, a method, not a property because i got an error with lazyLoading
{
return new List<Status>(StatusHistory) { LastStatus}; // List of all status (history + last)
}
}
public class Status{
public int Id { get; set; }
public int? WhatId { get; set; }
public What What { get; set; }
}
and don't forget to put in your context IsRequired(false) on the foreignKey :
builder.HasMany(x => x.Status).
WithOne(y => y.What).HasForeignKey(y => y.WhatId).IsRequired(false);
Like this, no more circular reference.

EF6: Single relationship table for multiple related entities

I have a EF Model with many entities, like Nodes, Attributes, Tags, etc.
There is also an "Alias" entity, and pretty much every other entity else can have a many-to-many relationship with Aliases. One of the undesired things about this is the number of tables that are created to track these relationships (eg. NodeAlias, AttributeAlias, etc.).
Are there any design alternatives that could map an Alias to all of the other entities in a single table? I was thinking maybe something along these lines if it's possible:
+---------+--------+-------------+-----------+
| AliasId | NodeId | AttributeId | TagId |
+---------+--------+-------------+-----------+
| 1 | 1 | 2 | 3 |
+---------+--------+-------------+-----------+
I updated my solution to provide many-to-many relationships between aliases and every other entity.
I intentionally posted this as a separate answer so that my previous answer can also remain here if anyone would need it.
Step #1: I created extension methods for getting and setting property values using reflection in a convenient way:
public static class ObjectExtensions
{
public static TResult GetPropertyValue<TResult>(this object entity, string propertyName)
{
object propertyValue = entity?.GetType().GetProperty(propertyName)?.GetValue(entity);
try
{
return (TResult)propertyValue;
}
catch
{
return default(TResult);
}
}
public static void SetPropertyValue(this object entity, string propertyName, object value)
{
entity?.GetType().GetProperty(propertyName)?.SetValue(entity, value);
}
}
Step #2: I updated the models to provide many-to-many relationship.
public class Node
{
[Key]
public int NodeId { get; set; }
public string Name { get; set; }
public virtual ICollection<AliasMapping> AliasMappings { get; set; }
}
public class Attribute
{
[Key]
public int AttributeId { get; set; }
public string Name { get; set; }
public virtual ICollection<AliasMapping> AliasMappings { get; set; }
}
public class Tag
{
[Key]
public int TagId { get; set; }
public string Name { get; set; }
public virtual ICollection<AliasMapping> AliasMappings { get; set; }
}
public class Alias
{
[Key]
public int AliasId { get; set; }
public string Name { get; set; }
public virtual ICollection<AliasMapping> AliasMappings { get; set; }
}
public class AliasMapping
{
[Key]
public int Id { get; set; }
[ForeignKey("Alias")]
public int AliasId { get; set; }
public Alias Alias { get; set; }
[ForeignKey("Node")]
public int? NodeId { get; set; }
public virtual Node Node { get; set; }
[ForeignKey("Attribute")]
public int? AttributeId { get; set; }
public virtual Attribute Attribute { get; set; }
[ForeignKey("Tag")]
public int? TagId { get; set; }
public virtual Tag Tag { get; set; }
}
Step #3: Due to relationship changes the MyDbContext could have been simplified as the [ForeignKey] data annotations are enough.
public class MyDbContext : DbContext
{
public DbSet<Node> Nodes { get; set; }
public DbSet<Attribute> Attributes { get; set; }
public DbSet<Tag> Tags { get; set; }
public DbSet<Alias> Aliases { get; set; }
public DbSet<AliasMapping> AliasMappings { get; set; }
}
Step #4: I also updated the extension methods so that you can create and remove alias mappings.
public static class AliasExtensions
{
public static void CreateMapping(this MyDbContext context, object entity, Alias alias)
{
if (entity == null || alias == null)
{
return;
}
string mappingEntityPropertyName = entity.GetType().Name;
string entityKeyPropertyName = String.Concat(mappingEntityPropertyName, "Id");
int entityId = entity.GetPropertyValue<int>(entityKeyPropertyName);
AliasMapping[] mappings =
context
.AliasMappings
.Where(mapping => mapping.AliasId == alias.AliasId)
.ToArray();
if (mappings.Any(mapping => mapping.GetPropertyValue<int?>(entityKeyPropertyName) == entityId))
{
// We already have the mapping between the specified entity and alias.
return;
}
bool usableMappingExists = true;
var usableMapping = mappings.FirstOrDefault(mapping => mapping.GetPropertyValue<int?>(entityKeyPropertyName) == null);
if (usableMapping == null)
{
usableMappingExists = false;
usableMapping = new AliasMapping()
{
Alias = alias
};
}
usableMapping.SetPropertyValue(mappingEntityPropertyName, entity);
usableMapping.SetPropertyValue(entityKeyPropertyName, entityId);
if (!usableMappingExists)
{
context.AliasMappings.Add(usableMapping);
}
// This step is required here, I think due to using reflection.
context.SaveChanges();
}
public static void RemoveMapping(this MyDbContext context, object entity, Alias alias)
{
if (entity == null || alias == null)
{
return;
}
string mappingEntityPropertyName = entity.GetType().Name;
string entityKeyPropertyName = String.Concat(mappingEntityPropertyName, "Id");
int entityId = entity.GetPropertyValue<int>(entityKeyPropertyName);
AliasMapping[] mappings =
context
.AliasMappings
.Where(mapping => mapping.AliasId == alias.AliasId)
.ToArray();
AliasMapping currentMapping = mappings.FirstOrDefault(mapping => mapping.GetPropertyValue<int?>(entityKeyPropertyName) == entityId);
if (currentMapping == null)
{
// There is no mapping between the specified entity and alias.
return;
}
currentMapping.SetPropertyValue(mappingEntityPropertyName, null);
currentMapping.SetPropertyValue(entityKeyPropertyName, null);
// This step is required here, I think due to using reflection.
context.SaveChanges();
}
}
Step #5: Updated the console app steps to align it with the changes.
class Program
{
static void Main(string[] args)
{
// Consider specify the appropriate database initializer!
// I use DropCreateDatabaseAlways<> strategy only for this example.
Database.SetInitializer(new DropCreateDatabaseAlways<MyDbContext>());
var aliases =
Enumerable
.Range(1, 9)
.Select(index => new Alias() { Name = String.Format("Alias{0:00}", index) })
.ToList();
var attributes =
Enumerable
.Range(1, 5)
.Select(index => new Attribute() { Name = String.Format("Attribute{0:00}", index) })
.ToList();
var nodes =
Enumerable
.Range(1, 5)
.Select(index => new Node() { Name = String.Format("Node{0:00}", index) })
.ToList();
var tags =
Enumerable
.Range(1, 5)
.Select(index => new Tag() { Name = String.Format("Tag{0:00}", index) })
.ToList();
using (var context = new MyDbContext())
{
context.Aliases.AddRange(aliases);
context.Nodes.AddRange(nodes);
context.Attributes.AddRange(attributes);
context.Tags.AddRange(tags);
// Always save changes after adding an entity but before trying to create a mapping.
context.SaveChanges();
// One Alias To Many Entities
context.CreateMapping(nodes[0], aliases[0]);
context.CreateMapping(nodes[1], aliases[0]);
context.CreateMapping(nodes[2], aliases[0]);
context.CreateMapping(nodes[3], aliases[0]);
context.CreateMapping(attributes[0], aliases[0]);
context.CreateMapping(attributes[1], aliases[0]);
context.CreateMapping(attributes[2], aliases[0]);
context.CreateMapping(tags[0], aliases[0]);
context.CreateMapping(tags[1], aliases[0]);
// One Entity To Many Aliases
context.CreateMapping(nodes[4], aliases[0]);
context.CreateMapping(nodes[4], aliases[1]);
context.CreateMapping(nodes[4], aliases[2]);
context.CreateMapping(attributes[3], aliases[1]);
context.CreateMapping(attributes[3], aliases[3]);
context.CreateMapping(tags[2], aliases[2]);
context.CreateMapping(tags[2], aliases[3]);
// Remove mapping
context.RemoveMapping(nodes[4], aliases[0]);
// Not really needed here as both 'CreateMapping' and 'RemoveMapping' save the changes
context.SaveChanges();
}
Console.Write("Press any key to continue . . .");
Console.ReadKey(true);
}
}
Please note: RemoveMapping() will not delete an AliasMapping even if no entity is associated with it! But CreateMapping() will make use of it later if needed. E.g. look at the screenshot below and check AliasMapping where Id = 5.
Screenshot about the execution result:
You were talking about many-to-many relationship but reading your post I think it is more likely a "special one-to-many" relationship, actually "combined multiple one-to-one" relationship as I see that an Alias can be mapped to a single Node AND/OR to a single Attribute AND/OR to a single Tag.
I think I found a solution for this case.
If it's not the case and an Alias can be mapped to multiple Node AND/OR to multiple Attribute AND/OR to multiple Tag then I think this solution below needs only a small change. :)
Step #1 - These are my example models
public class Node
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual AliasMapping AliasMapping { get; set; }
}
public class Attribute
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual AliasMapping AliasMapping { get; set; }
}
public class Tag
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual AliasMapping AliasMapping { get; set; }
}
public class Alias
{
[Key]
public int AliasId { get; set; }
public string Name { get; set; }
public virtual AliasMapping AliasMapping { get; set; }
}
Step #2 - Creating the custom mapping table
public class AliasMapping
{
[Key]
[ForeignKey("Alias")]
public int AliasId { get; set; }
public Alias Alias { get; set; }
[ForeignKey("Node")]
public int NodeId { get; set; }
public virtual Node Node { get; set; }
[ForeignKey("Attribute")]
public int AttributeId { get; set; }
public virtual Attribute Attribute { get; set; }
[ForeignKey("Tag")]
public int TagId { get; set; }
public virtual Tag Tag { get; set; }
}
Step #3 - Creating the DbContext
public class MyDbContext : DbContext
{
public DbSet<Node> Nodes { get; set; }
public DbSet<Attribute> Attributes { get; set; }
public DbSet<Tag> Tags { get; set; }
public DbSet<Alias> Aliases { get; set; }
public DbSet<AliasMapping> AliasMappings { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder
.Entity<AliasMapping>()
.HasOptional(mapping => mapping.Attribute)
.WithOptionalPrincipal(attribute => attribute.AliasMapping)
.Map(config => config.MapKey("AliasId"));
modelBuilder
.Entity<AliasMapping>()
.HasOptional(mapping => mapping.Node)
.WithOptionalPrincipal(node => node.AliasMapping)
.Map(config => config.MapKey("AliasId"));
modelBuilder
.Entity<AliasMapping>()
.HasOptional(mapping => mapping.Tag)
.WithOptionalPrincipal(tag => tag.AliasMapping)
.Map(config => config.MapKey("AliasId"));
}
}
Step #4 - Creating extension method so that creating a relationship will be easy
public static class AliasExtensions
{
public static void CreateMapping<TEntity>(this MyDbContext context, TEntity entity, Alias alias)
{
string mappingEntityPropertyName = typeof(TEntity).Name;
string entityKeyPropertyName = String.Concat(mappingEntityPropertyName, "Id");
bool entityExists = true;
var mapping = context.AliasMappings.Find(alias.AliasId);
if (mapping == null)
{
entityExists = false;
mapping = new AliasMapping()
{
Alias = alias
};
}
typeof(AliasMapping)
.GetProperty(mappingEntityPropertyName)
.SetValue(mapping, entity);
typeof(AliasMapping)
.GetProperty(entityKeyPropertyName)
.SetValue(mapping, typeof(TEntity).GetProperty("Id").GetValue(entity));
if (!entityExists)
{
context.AliasMappings.Add(mapping);
}
}
}
Step #5 - Created a console app to see this working
class Program
{
static readonly Random rnd = new Random(DateTime.Now.TimeOfDay.Milliseconds);
static void Main(string[] args)
{
Database.SetInitializer(new DropCreateDatabaseAlways<MyDbContext>());
var aliases =
Enumerable
.Range(1, 9)
.Select(index => new Alias() { Name = String.Format("Alias{0:00}", index) })
.ToList();
var attributes =
Enumerable
.Range(1, 5)
.Select(index => new Attribute() { Name = String.Format("Attribute{0:00}", index) })
.ToList();
var nodes =
Enumerable
.Range(1, 5)
.Select(index => new Node() { Name = String.Format("Node{0:00}", index) })
.ToList();
var tags =
Enumerable
.Range(1, 5)
.Select(index => new Tag() { Name = String.Format("Tag{0:00}", index) })
.ToList();
using (var context = new MyDbContext())
{
context.Aliases.AddRange(aliases);
context.Nodes.AddRange(nodes);
context.Attributes.AddRange(attributes);
context.Tags.AddRange(tags);
context.SaveChanges();
// Associate aliases to attributes
attributes.ForEach(attribute =>
{
var usableAliases = aliases.Where(alias => alias.AliasMapping?.Attribute == null).ToList();
var selectedAlias = usableAliases[rnd.Next(usableAliases.Count)];
context.CreateMapping(attribute, selectedAlias);
});
// Associate aliases to nodes
nodes.ForEach(node =>
{
var usableAliases = aliases.Where(alias => alias.AliasMapping?.Node == null).ToList();
var selectedAlias = usableAliases[rnd.Next(usableAliases.Count)];
context.CreateMapping(node, selectedAlias);
});
// Associate aliases to tags
tags.ForEach(tag =>
{
var usableAliases = aliases.Where(alias => alias.AliasMapping?.Tag == null).ToList();
var selectedAlias = usableAliases[rnd.Next(usableAliases.Count)];
context.CreateMapping(tag, selectedAlias);
});
context.SaveChanges();
}
Console.Write("Press any key to continue . . .");
Console.ReadKey(true);
}
}

Entity framework replaces delete+insert with an update. How to turn it off

I want to remove a row in database and insert it again with the same Id, It sounds ridiculous, but here is the scenario:
The domain classes are as follows:
public class SomeClass
{
public int SomeClassId { get; set; }
public string Name { get; set; }
public virtual Behavior Behavior { get; set; }
}
public abstract class Behavior
{
public int BehaviorId { get; set; }
}
public class BehaviorA : Behavior
{
public string BehaviorASpecific { get; set; }
}
public class BehaviorB : Behavior
{
public string BehaviorBSpecific { get; set; }
}
The entity context is
public class TestContext : DbContext
{
public DbSet<SomeClass> SomeClasses { get; set; }
public DbSet<Behavior> Behaviors { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
modelBuilder.Entity<SomeClass>()
.HasOptional(s => s.Behavior)
.WithRequired()
.WillCascadeOnDelete(true);
}
}
Now this code can be executed to demonstrate the point
(described with comments in the code below)
using(TestContext db = new TestContext())
{
var someClass = new SomeClass() { Name = "A" };
someClass.Behavior = new BehaviorA() { BehaviorASpecific = "Behavior A" };
db.SomeClasses.Add(someClass);
// Here I have two classes with the state of added which make sense
var modifiedEntities = db.ChangeTracker.Entries()
.Where(entity => entity.State != System.Data.Entity.EntityState.Unchanged).ToList();
// They save with no problem
db.SaveChanges();
// Now I want to change the behavior and it causes entity to try to remove the behavior and add it again
someClass.Behavior = new BehaviorB() { BehaviorBSpecific = "Behavior B" };
// Here it can be seen that we have a behavior A with the state of deleted and
// behavior B with the state of added
modifiedEntities = db.ChangeTracker.Entries()
.Where(entity => entity.State != System.Data.Entity.EntityState.Unchanged).ToList();
// But in reality when entity sends the query to the database it replaces the
// remove and insert with an update query (this can be seen in the SQL Profiler)
// which causes the discrimenator to remain the same where it should change.
db.SaveChanges();
}
How to change this entity behavior so that delete and insert happens instead of the update?
A possible solution is to make the changes in 2 different steps: before someClass.Behavior = new BehaviorB() { BehaviorBSpecific = "Behavior B" }; insert
someClass.Behaviour = null;
db.SaveChanges();
The behaviour is related to the database model. BehaviourA and B in EF are related to the same EntityRecordInfo and has the same EntitySet (Behaviors).
You have the same behaviour also if you create 2 different DbSets on the context because the DB model remains the same.
EDIT
Another way to achieve a similar result of 1-1 relationship is using ComplexType. They works also with inheritance.
Here an example
public class TestContext : DbContext
{
public TestContext(DbConnection connection) : base(connection, true) { }
public DbSet<Friend> Friends { get; set; }
public DbSet<LessThanFriend> LessThanFriends { get; set; }
}
public class Friend
{
public Friend()
{Address = new FullAddress();}
public int Id { get; set; }
public string Name { get; set; }
public FullAddress Address { get; set; }
}
public class LessThanFriend
{
public LessThanFriend()
{Address = new CityAddress();}
public int Id { get; set; }
public string Name { get; set; }
public CityAddress Address { get; set; }
}
[ComplexType]
public class CityAddress
{
public string Cap { get; set; }
public string City { get; set; }
}
[ComplexType]
public class FullAddress : CityAddress
{
public string Street { get; set; }
}

EF 6 Codefirst -Setting default value for a property defined in base class using fluent API

I have a base class which has audit properties like
public abstract class BaseModel
{
[Column(Order = 1)]
public long Id { get; set; }
public long CreatedBy { get; set; }
public DateTime CreatedDate { get; set; }
public long ModifiedBy { get; set; }
public DateTime ModifiedDate { get; set; }
public bool IsActive { get; set; }
}
All my poco classes derive from this class.
I am trying to set a default value to the IsActive properties. I am not keen on using annotations and hence was wandering if I can work this using fluent API.
I tried this but it does not work. Seems like it creates a new table named BaseModel
modelBuilder.Entity<BaseModel>()
.Property(p => p.IsActive)
.HasColumnAnnotation("DefaultValue", true);
Can any one suggest a way here?
There is no way to do this. It can't set default values with Entity Framework. Instead you can use the constructor
public abstract class BaseModel
{
protected BaseModel()
{
IsActive = true;
}
}
I have resolved this problem by overriding the SaveChanges method. See below for my solution.
Solution Explain
i) Override the SaveChanges method in the DbContext class.
public override int SaveChanges()
{
return base.SaveChanges();
}
ii) Write logic to set default values
public override int SaveChanges()
{
//set default value for your property
foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("YOUR_PROPERTY") != null))
{
if (entry.State == EntityState.Added)
{
if (entry.Property("YOUR_PROPERTY").CurrentValue == null)
entry.Property("YOUR_PROPERTY").CurrentValue = YOUR_DEFAULT_VALUE;
}
}
return base.SaveChanges();
}
Example
i) Create Base Class
public abstract class BaseModel
{
[Column(Order = 1)]
public long Id { get; set; }
public long CreatedBy { get; set; }
public DateTime CreatedDate { get; set; }
public long ModifiedBy { get; set; }
public DateTime ModifiedDate { get; set; }
public bool IsActive { get; set; }
}
ii) override SaveChanges
public override int SaveChanges()
{
//set default value for IsActive property
foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("IsActive") != null))
{
if (entry.State == EntityState.Added)
{
if(entry.Property("IsActive").CurrentValue == null)
entry.Property("IsActive").CurrentValue = false;
}
}
return base.SaveChanges();
}