How to clean-up an Entity Framework object context?

Question

I am adding several entities to an object context.

try {     forach (var document in documents)     {         this.Validate(document); // May throw a ValidationException.          this.objectContext.AddToDocuments(document);     }      this.objectContext.SaveChanges(); } catch {     // How to clean-up the object context here?      throw; } 

If some of the documents pass the the validation and one fails, all documents that passed the validation remain added to the object context. I have to clean-up the object context because it may be reused and the following can happen.

var documentA = new Document { Id = 1, Data = "ValidData" }; var documentB = new Document { Id = 2, Data = "InvalidData" }; var documentC = new Document { Id = 3, Data = "ValidData" };  try {     // Adding document B will cause a ValidationException but only     // after document A is added to the object context.     this.DocumentStore.AddDocuments(new[] { documentA, documentB, documentC }); } catch (ValidationException) { }  // Try again without the invalid document B. This causes an exception because // of a duplicate primary key - document A with id 1 is added a second time. this.DocumentStore.AddDocuments(new[] { documentA, documentC }); 

This will again add document A to the object context and in consequence SaveChanges() will throw an exception because of a duplicate primary key.

So I have to remove all already added documents in the case of an validation error. I could of course perform the validation first and only add all documents after they have been successfully validated but sadly this does not solve the whole problem - if SaveChanges() fails, all documents still remain added but unsaved.

I tried to detach all objects returned by

 this.objectContext.ObjectStateManager.GetObjectStateEntries(EntityState.Added) 

but I am getting a exception stating that the object is not attached. So how do I get rid of all added but unsaved objects?

Answer 1

Daniel's answer worked for me, however the EntityFramework API is different in version 6+. Here is a method I added to my custom repository container that will detach all entities from the DbContext's ChangeTracker:

    /// <summary>     /// Detaches all of the DbEntityEntry objects that have been added to the ChangeTracker.     /// </summary>     public void DetachAll() {          foreach (DbEntityEntry dbEntityEntry in this.Context.ChangeTracker.Entries().ToArray()) {              if (dbEntityEntry.Entity != null) {                 dbEntityEntry.State = EntityState.Detached;             }         }     } 

Answer 2

It was just a trivial bug but I am going to leave the question here - maybe it helps others.

I had the following

var objectStateEntries = this.objectContext                              .ObjectStateManager                              .GetObjectStateEntries(EntityState.Added);  foreach (var objectStateEntry in objectStateEntries) {     this.objectContext.Detach(objectStateEntry); } 

while I wanted the following

foreach (var objectStateEntry in objectStateEntries) {     this.objectContext.Detach(objectStateEntry.Entity); } 

and couldn't see it.