Hi,
I am attempting to implement optimistic locking in order to handle concurrency issues.
I have added the following field to my entities:
[Timestamp]
public byte[] RowVersion { get; set; }
According to the EF documentation, this is all that is required, as long as the initial row version value is supplied with the update. However, I cannot seem to get this to work in ASPNet Zero.
Should I be implementing a custom repository to perform the updates? And if so, how do I prevent the update that is automatically called by the Unit Of Work manager?
Thank you
18 Answer(s)
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Did you supply the initial row version? What's not working?
You should not need to implement a custom repository for this.
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Hi,
Basically, I am not getting a DbUpdateConcurrencyException when I perform a second update on stale data. I have checked that the row version updates in the database, but EF does not object to performing the second update with the old row version.
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Many thanks, that is probably the issue I am having.
The (best) solution to this problem is to set the Row Version in the Original Values collection prior to update. I will therefore need to override the update method. I assume the way to do this is via a custom repository?
If so, how do I get the framework to call this rather than the default Update method? If I call it manually, how do I ensure that the default Update method doesn't get called by the Unit Of Work manager?
Cheers
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I will therefore need to override the update method. I assume the way to do this is via a custom repository?
Actually, you might want to override ApplyAbpConceptsForModifiedEntity in YourDbContext instead (reason below).
If so, how do I get the framework to call this rather than the default Update method? If I call it manually, how do I ensure that the default Update method doesn't get called by the Unit Of Work manager?
The framework (and UnitOfWorkManager) doesn't call Update, but automatically saves changes (incl. ApplyAbpConcepts).
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Hi,
I don't seem to have this method available. I am using v4 of Aspnet Zero, MVC, jQuery.
Not quite sure how I would achieve my aim with this method anyway?
Cheers
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I don't seem to have this method available.
Can you show what you did?
Not quite sure how I would achieve my aim with this method anyway?
Simple:
protected override void ApplyAbpConceptsForModifiedEntity(DbEntityEntry entry, long? userId, EntityChangeReport changeReport) { if (entry.Entity is MyRowVersionEntity) { entry.OriginalValues["Timestamp"] = entry.CurrentValues["Timestamp"]; } base.ApplyAbpConceptsForModifiedEntity(entry, userId, changeReport); } -
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Thanks for the explanation.
I have been unable to code anything, as the version of Abp I am using does not have the ApplyAbpConceptsForModifiedEntity method available for override. The Abp.EntityFramework dll is at version 2.01. I am using aspnet zero v4
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I'll update and give it a go.
Many thanks.
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Many thanks, the system is now picking up concurrency issue.
One final problem I am having. I cannot work out how to provide a sensible error message to the users in this instance. The Dynamic Web Api returns a generic message. Is there a way I can override this behaviour when encountering a concurrency exception?
Cheers
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You can override SaveChanges and SaveChangesAsync in YourDbContext:
public override int SaveChanges() { try { return base.SaveChanges(); } catch (DbUpdateConcurrencyException innerException) { throw new UserFriendlyException("Concurrency exception!", innerException.Message, innerException); } } -
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Nice. Thank you.
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Hi,
I am having an issue with the upgrade. I have the following service:
Task<IEnumerable<SelectListItem>> GetPayrollGroupsForDropdown(long? userId);When I call this service via dynamic web with an 'undefined' parameter, I am getting the following validation error:
"The value 'undefined' is not valid for Nullable'1"
This has only started happening since the upgrade.
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Please post a new topic. Remember to state which version you upgraded from and to.
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<cite>aaron: </cite> You need Abp.EntityFramework v2.3.0, which should be compatible with ASP.NET Zero v4.0 to v4.4. ASP.NET Zero v4.5 to v4.6 should use Abp.EntityFramework v3.1.2.
Hi aaron,
Which version should I upgrade to if I'm using MVC5AJ1? Because I'm not able to upgrade to the latest version, which is version 3.2.3 due to my .NETFramework is 4.6.1
Thanks. /Tommy
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Hi Tommy, can you try Abp.EntityFramework v2.3.0?
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<cite>aaron: </cite> Hi Tommy, can you try Abp.EntityFramework v2.3.0?
Hi aaron,
Able to update now.
What should I do in order to get the exception? Follow the stackoverflow approach?
Thanks. /Tommy
