c# Json反序列化表达式

本文关键字：表达式 反序列化 Json | 更新日期: 2023-09-27 18:02:51

也许有人知道解决办法。我不能反序列化表达式。

客户端

: 

 var expresion= (Expression<Func<Company, bool>>)(model => model.Id ==id);
 var respond = new JObject();
 respond .Add("Expression", JToken.FromObject(expresion));
服务器端

: 

JsonSerializer serializer = new JsonSerializer();
serializer.ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor;
T p = (T)serializer.Deserialize(new JTokenReader(jObject), typeof(T));

: 

{"Unable to find a constructor to use for type System.Linq.Expressions.Expression`1[System.Func`2[HostStorageModels.Company,System.Boolean]]. A class should either have a default constructor, one constructor with arguments or a constructor marked with the JsonConstructor attribute. Path 'Expression.Type'."}

c# Json反序列化表达式

我认为它显式地告诉您没有构造函数来构建表达式。如果您在MSDN文档中检查Expression Constructor()，您将看到它是受保护的。您可以尝试以其他可序列化的格式发送表达式，并在另一端接收到它时重新构建它。

https://github.com/6bee/Remote.Linq

var query = (Expression<Func<Person, bool>>)(model => model.FirstName == "test2");
var remoteExpression = query.ToRemoteLinqExpression();
var request = new Request<Person>
{
       Items = new List<Person>()
       {
          new Person() { FirstName = "test", Id = 1 },
           new Person() { FirstName = "test2", Id = 2 }
       },
      Expression = remoteExpression
};
var serializerSettings = new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.Auto };
string jsonString = JsonConvert.SerializeObject(request, serializerSettings);
var result = JsonConvert.DeserializeObject<Request<Person>>(jsonString, serializerSettings);
var expresion = result.Expression.ToLinqExpression<Person, bool>();
var filtered = request.Items.Where(expresion.Compile()).ToList();
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