RavenDB:将自动增量添加到ID以外的其他属性 [英] RavenDB: Add auto increment to other property than ID

问题描述

是否有一种方法可以在属性上放置一个属性，以告知RavenDB使用该属性，就像ID属性一样，并在其上自动增加计数?

Is there a way to put an attribute on a property to tell RavenDB to use this property just like the ID-property and put an auto increment on it?

伪代码:

public class MyObj {
    public string Id { get; set; }
    [Increment]
    public int OtherProp { get; set; }
}

推荐答案

Dynamicus指向正确的解决方案，但是我想提供确切的示例代码，以帮助其他Stackoverflow用户，也可能使解决方案更易于搜索.

Dynamicus points to the correct solution, but I'd like to give the exact sample-code for helping other Stackoverflow-users and maybe also making the solution more searchable.

关于问题的示例代码，这是解决方案:

In relation to the question's example-code, here is the solution:

public class OtherPropIncrementListener : IDocumentStoreListener
{
    HiLoKeyGenerator _generator;
    IDocumentStore _store;

    public OtherPropIncrementListener(IDocumentStore store)
    {
        this._store = store;
        _generator = new HiLoKeyGenerator(store.DatabaseCommands, "MyObjs", 1);
    }

    public void AfterStore(string key, object entityInstance, RavenJObject metadata)
    {
    }

    public bool BeforeStore(string key, object entityInstance, RavenJObject metadata, RavenJObject original)
    {
        var myObj = entityInstance as MyObj;
        if(myObj != null && myObj.OtherProp == 0)
        {
            string documentKey = _generator.GenerateDocumentKey(_store.Conventions, entityInstance);
            myObj.OtherProp = int.Parse(documentKey.Substring(documentKey.IndexOf("/") + 1));
            return true;
        }

        return false;
    }
}

然后，在初始化DocumentStore之后，添加以下代码以使上面的侦听器起作用:

Then where after you initialize your DocumentStore you add this code to make above listener work:

documentStore.RegisterListener(new OtherPropIncrementListener(documentStore));

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