How to override the ef core to write data automatically or log to file? - asp.net-core

Question

I am using asp.net core + ef core. I can add delete get or update data to the database.
But can it be true that when I do these operations it can auto log to file or database the userinfo and datetime?
If I am updating data the data will auto update the LastModifiedDateTime and ModifyUserId property.
or log it to file?
for example:
If I update the database
await _context.SaveChangesAsync(cancellationToken);
I can do this:
public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = new CancellationToken())
{
foreach (var entry in ChangeTracker.Entries<AuditableEntity>())
{
switch (entry.State)
{
case EntityState.Added:
entry.Entity.CreatedBy = _currentUserService.UserId;
entry.Entity.Created = _dateTime.Now;
break;
case EntityState.Modified:
entry.Entity.LastModifiedBy = _currentUserService.UserId;
entry.Entity.LastModified = _dateTime.Now;
break;
}
}
return base.SaveChangesAsync(cancellationToken);
}
no need I specify the property but override it to log it automatically?
how to set the property of each entity?
Then I can know when and who do the update?

Answer 1

Create new base model class. Every models must have at least one or more columns that are same such as ID, CreatedBy, etc. Then link base model with all your models.
BaseModel.cs
public class BaseModel
{
public int ID { get; set; }
public DateTime? Created { get; set; }
public string CreatedBy { get; set; }
public DateTime? LastModified { get; set; }
public string LastModifiedBy { get; set; }
}
User.cs
public class User : BaseModel
{
public string Name { get; set; }
public int Age {get; set; }
}
YourDbContext.cs
public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = new CancellationToken())
{
var entities = ChangeTracker.Entries().Where(x => x.Entity is BaseModel && (x.State == EntityState.Added || x.State == EntityState.Modified));
DateTime dt = DateTime.Now;
foreach (var entity in entities)
{
if (entity.State == EntityState.Added)
{
((BaseModel)entity.Entity).CreatedBy = _currentUserService.UserId;
((BaseModel)entity.Entity).Created = dt;
}
else if (entity.State == EntityState.Modified)
{
((BaseModel)entity.Entity).ModifiedBy = _currentUserService.UserId;
((BaseModel)entity.Entity).LastModified = dt;
}
}
return base.SaveChangesAsync(cancellationToken);
}