无法执行保存，因为文档已被会话修改，并且还参与延迟的PATCH命令RavenDB

Question

我正在尝试在Ravendb c＃中执行补丁命令，并且收到此错误。我要做的是创建一个新条目然后尝试保存它。

以下是处理json序列化，反序列化的相关类。

    public class Merchant
{
    [JsonProperty(PropertyName ="Id")]
    public string Id { get; set; }
    [JsonProperty(PropertyName = "name")]
    public string name { get; set; }
    [JsonProperty(PropertyName = "venues")]
    public System.Collections.Generic.List<Venue> venues { get; set; }
    [JsonProperty(PropertyName ="files")]
    public System.Collections.Generic.List<File> files { get; set; }
}

public class Venue
{
    [JsonProperty(PropertyName = "Id")]
    public string Id { get; set; }
    [JsonProperty(PropertyName = "name")]
    public string name { get; set; }
    [JsonProperty(PropertyName = "tills")]
    public List<Till> tills { get; set; }
    [JsonProperty(PropertyName = "files")]
    public System.Collections.Generic.List<File> files { get; set; }
}

public class Till
{
    [JsonProperty(PropertyName = "Id")]
    public string Id { get; set; }
    [JsonProperty(PropertyName = "name")]
    public string name { get; set; }
    [JsonProperty(PropertyName = "files")]
    public System.Collections.Generic.List<File> files { get; set; }
    [JsonProperty(PropertyName = "logs")]
    public List<Log> logs { get; set; }
}

//这是首先调用的函数。

 public bool AddMerchant(Merchant m)
    {
        bool returnbool = false; // set to false at begining.
        if (DoesServiceExist("RavenDB"))
        {
            StartService("RavenDB");
            returnbool = true;

            using (IDocumentSession session = store.OpenSession())
            {
                session.Store(m);
                session.SaveChanges();
            }
        }
        return returnbool;
    }

这是我的问题开始的地方，我调用了这个函数，它告诉我由于它在延迟补丁语句中而无法执行此操作。

 public void AddVenue(string idArg, Venue venue = null)
    {
        using (IDocumentSession session = store.OpenSession())
        {

            var merchant = session.Load<Merchant>(idArg);
            List<Venue> venuesList = new List<Venue>();
            if (merchant.venues == null) { session.Advanced.Patch(merchant, m => m.venues, venuesList); }
            else
            {
                session.Advanced.Patch(merchant,
                x => x.venues,
                venues => venues.Add(venue));
            }
            session.SaveChanges();

        }
    }

经过研究，我相信ravendb的Defer指的是：

session.advanced().defer(new PatchCommandData("blogposts/1", null, patchRequest, null));

我从来没有打过电话。

欢迎任何帮助。

//最终答案如下，谢谢。

    public void AddVenue(Merchant merchant, Venue venue = null)
    {
        using (IDocumentSession session = store.OpenSession())
        {
            Merchant merchantLocal = session.Load<Merchant>(merchant.Id);
            var changeVector = session.Advanced.GetChangeVectorFor(merchantLocal);
            if(merchantLocal.venues == null) { merchantLocal.venues = new List<Venue>(); }
            merchantLocal.venues.Add(venue);
            session.Store(merchantLocal, changeVector, merchantLocal.Id);
            session.SaveChanges();
        }
    }

Answer 1

正如错误所述，场地属性已发生变化，因此在'SaveChanges'时，补丁操作无法应用。

阅读有关在https://github.com/ravendb/book/blob/v4.0/Ch04/Ch04.md#patching-documents-and-concurrent-modifications中修补文档和并发修改的信息

1. 如果您知道文档ID，则根本不要使用Load。 只需致电Patch和SaveChanges。 要么
2. 仅在某些条件下应用补丁

using (var session = store.OpenSession())
{
    var merchant = session.Load<Merchant>(idArg);

    if (merchant.venues  !=  SOME_CONDITION )
    throw new
        InvalidOperationException("venues have changed. Cannot apply patch Operation");

    List<Venue> venuesList = new List<Venue>();

    if (merchant.venues == null) { 
        session.Advanced.Patch(merchant, m => m.venues, venuesList); 
    }
    else {
        session.Advanced.Patch(merchant,
        x => x.venues,
        venues => venues.Add(venue));
    }

    session.SaveChanges();
}