如果我创建了一个隐式类型转换运算符,我可以让 Raven DB 像序列化字符串一样序列化对象吗?



我有一个看起来像这样的类:

public class MyClass
{
    string _value;
    public static implicit operator MyClass (string value)
    {
        return new MyClass(value);
    }
    MyClass(string value)
    {
        // Do something...
        _value = value;
    }
    public override string ToString()
    {
         // Do something...
         return _value;
    }
}

因此,我可以像这样使用类:

MyClass a = "Hello!";

但是在 Raven DB 中,它只会像

"SomeProperty": {}

因为它没有公共属性。而且没用。

为了解决这个问题,我会将_value私有成员变成公共财产,如下所示:

public string Value { get; set; }

和乌鸦数据库将存储

"SomeProperty": { "Value": "Hello!" }

它将是可反序列化的。

但我不想要这个公共财产。我可以以某种方式使 Raven DB 序列化和反序列化类,就像字符串一样吗?喜欢:

"SomeProperty": "Hello!"
嗨,

我知道这很旧,但我想我会在 Ayendes 的回复中添加一些补充,以帮助像我这样的人遇到同样的问题并花了几个小时在论坛上寻找答案(其中有一些,但没有一个有任何你可以遵循的例子(,这并不难弄清楚,但有了一个例子,我本可以在 10 分钟内解决这个问题,而不是花费几个小时。

我的问题是我们的应用程序中有自定义值类型结构,我将使用的示例是电子邮件地址。不幸的是,在 Ravendb 中,如果不定义自定义序列化器,我们就无法针对这些类型运行查询。

我们的值类型如下所示:

[DataContract(Namespace = DataContractNamespaces.ValueTypes)]
public struct EmailAddress : IEquatable<EmailAddress>
{
    private const char At = '@';
    public EmailAddress(string value) : this()
    {
        if (value == null)
        {
            throw new ArgumentNullException("value");
        }
        this.Value = value;
    }
    public bool IsWellFormed
    {
        get
        {
            return Regex.IsMatch(this.Value, @"w+([-+.']w+)*@w+([-.]w+)*.w+([-.]w+)*");
        }
    }
    public string Domain
    {
        get
        {
            return this.Value.Split(At)[1];
        }
    }
    [DataMember(Name = "Value")]
    private string Value { get; set; }
    public static bool operator ==(EmailAddress left, EmailAddress right)
    {
        return left.Equals(right);
    }
    public static bool operator !=(EmailAddress left, EmailAddress right)
    {
        return !left.Equals(right);
    }
    public override bool Equals(object obj)
    {
        if (obj == null)
        {
            return false;
        }
        return this.Equals(new EmailAddress(obj.ToString()));
    }
    public override int GetHashCode()
    {
        return this.Value.GetHashCode();
    }
    public override string ToString()
    {
        return this.Value;
    }
    public bool Equals(EmailAddress other)
    {
        return other != null && this.Value.Equals(other.ToString(), StringComparison.OrdinalIgnoreCase);
    }
}

我们想要保存和查询的文档类型如下所示

public class Customer
{
    public Guid Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public EmailAddress Email { get; set; }
}

自定义序列化程序将我们的电子邮件存储为原始字符串,然后在检索时将其转换回其值类型,如下所示:

public class EmailConverterTest : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(EmailAddress);
    }
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        EmailAddress actualAddress =  new EmailAddress(reader.Value.ToString());
        return actualAddress;
    }
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        EmailAddress actualAddress = (EmailAddress)value;
        string stringEmail = actualAddress.ToString();
        writer.WriteValue(stringEmail);
    }
}

最后,我将其连接起来,并能够按如下方式查询所有内容:

    public static void serializercustom(Newtonsoft.Json.JsonSerializer serialiser)
    {
        serialiser.Converters.Add(new EmailConverterTest());
    }
    public static void TestCustomer()
    {
        using (var documentStore = new DefaultDocumentStore())
        {
            documentStore.ConnectionStringName = Properties.Settings.Default.SandBoxConnection;
            documentStore.Initialize();
            documentStore.Conventions.CustomizeJsonSerializer = new Action<Newtonsoft.Json.JsonSerializer>(serializercustom);
            var customer = new Customer
            {
                Id = Guid.NewGuid(),
                FirstName = "TestFirstName",
                LastName = "TestLastName",
                Email = new EmailAddress("testemail@gmail.com")
            };
            // Save and retrieve the data
            using (var session = documentStore.OpenSession())
            {
                session.Store(customer);
                session.SaveChanges();
            }
            using (var session = documentStore.OpenSession())
            {
                var addressToQuery = customer.Email;
                var result = session.Query<Customer>(typeof(CustomerEmailIndex).Name).Customize(p => p.WaitForNonStaleResults()).Where(p => p.Email == addressToQuery);
                Console.WriteLine("Number of Results {0}", result.Count()); // This always seems to return the matching document
            }
        }
    } 

你可以编写一个JsonConverter,并教RavenDB如何存储数据。编写转换器后,在存储中注册它。约定。自定义序列化程序事件。

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