Unchanged objects in Entity Framework 6

Question

I have silverlight application. This is an invoke operation (in Open Ria Service - WCF Ria Service open source version) with Entity Framework 6.

    public List<VaultAmount> GetCurrentVaultAmounts(Guid vaultId)
    {
        return this.DbContext.VaultAmounts
            .Include(v => v.VaultAmountQuantities)
            .Include(v => v.VaultCurrency)
            .Include(v => v.Vault)
            .Include(v => v.VaultAmountQuantities.Select(vaq => vaq.VaultCurrency))
            .Where(v => v.VaultId == vaultId && v.IsCurrent).ToList();
    }

    [Invoke]
    public void UpdateVaultRemainders(List<VaultAmountQuantity> updatedQuantities, string comment, Guid userId,
        string friendlyName,
        Guid vaultAmountId, int currencyId)
    {
        VaultAmount vaultAmount =
            this.DbContext.VaultAmounts
                .Include("Vault")
                .SingleOrDefault(va => va.VaultAmountId == vaultAmountId);

        if (vaultAmount == null && vaultAmount.Vault == null) return;

        //Get FromVault and ToVault with amounts and updatedQuantities
        List<VaultAmount> currentAmounts = GetCurrentVaultAmounts(vaultAmount.Vault.VaultId);
        //Vault vault = GetVaultWithCurrentAmountsAndQuantitiesById(vaultAmount.Vault.VaultId);

        var helper = new RemainderVAHelper(currentAmounts, userId, friendlyName, currencyId, updatedQuantities,
            comment,
            BS2VaultEventTypes.Correction);

        //................................

        foreach (var amount in currentAmounts)
        {
            if (amount.IsCurrent == false)
            {
                DbEntityEntry<VaultAmount> entityEntry = this.DbContext.Entry(amount);
                entityEntry.State = EntityState.Modified;
            }
        }
        this.DbContext.SaveChanges();
    }

In RemainderVAHelper class I am changing currentAmounts objects, set IsCurrent property to false. But currentAmounts objects entityEntry.State are still Unchanged . Why? Yes, I can set their states as Modified (as I am doing in method), but I think it is not very good thing. Can you tell me why my objects state doesn't changes to Modified ?

Answer 1

如果您不使用更改跟踪代理，则在调用DetectChanges或调用SaveChanges（调用DetectChanges）之前，EF无法知道您是否修改了属性。