I have a class call Person:
public class Person
{
public int id{get;set;}
public string name{get;set;}
//and many others
}
Is there a way to set value to property not in the regular way like: person.id=1
but use something like string str="id" and person.str=1?
I want that because I have many properties and I recieve list with the name of the property and his value. so I want to avoid long switch-case and use :
foreach(var item in MyList.Keys)
{
person.item=MyList[item];
}
public class Person
{
public int Id{get;set;}
public string Name{get;set;}
//and many others
}
Dictionary<string,object> properties = new Dictionary<string,object>();
properties.Add("Id",1);
properties.Add("Name", "TestName");
Person p = new Person();
foreach (KeyValuePair<string, object> obj in properties)
{
p.GetType().GetProperty(obj.Key).SetValue(p, obj.Value, null);
}
This might works for you. Make sure you have proper casing of propertyname.
You can use reflection for this or the dynamic type in .NET 4.0.
Related
With a simple class/interface like this
public interface IThing
{
string Name { get; set; }
}
public class Thing : IThing
{
public int Id { get; set; }
public string Name { get; set; }
}
How can I get the JSON string with only the "Name" property (only the properties of the underlying interface) ?
Actually, when i make that :
var serialized = JsonConvert.SerializeObject((IThing)theObjToSerialize, Formatting.Indented);
Console.WriteLine(serialized);
I get the full object as JSON (Id + Name);
The method I use,
public class InterfaceContractResolver : DefaultContractResolver
{
private readonly Type _InterfaceType;
public InterfaceContractResolver (Type InterfaceType)
{
_InterfaceType = InterfaceType;
}
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
//IList<JsonProperty> properties = base.CreateProperties(type, memberSerialization);
IList<JsonProperty> properties = base.CreateProperties(_InterfaceType, memberSerialization);
return properties;
}
}
// To serialize do this:
var settings = new JsonSerializerSettings() {
ContractResolver = new InterfaceContractResolver (typeof(IThing))
};
string json = JsonConvert.SerializeObject(theObjToSerialize, settings);
Improved version with nested interfaces + support for xsd.exe objects
Yet another variation here. The code came from http://www.tomdupont.net/2015/09/how-to-only-serialize-interface.html with the following improvements over other answers here
Handles hierarchy, so if you have an Interface2[] within an Interface1 then it will get serialized.
I was trying to serialize a WCF proxy object and the resultant JSON came up as {}. Turned out all properties were set to Ignore=true so I had to add a loop to set them all to not being ignored.
public class InterfaceContractResolver : DefaultContractResolver
{
private readonly Type[] _interfaceTypes;
private readonly ConcurrentDictionary<Type, Type> _typeToSerializeMap;
public InterfaceContractResolver(params Type[] interfaceTypes)
{
_interfaceTypes = interfaceTypes;
_typeToSerializeMap = new ConcurrentDictionary<Type, Type>();
}
protected override IList<JsonProperty> CreateProperties(
Type type,
MemberSerialization memberSerialization)
{
var typeToSerialize = _typeToSerializeMap.GetOrAdd(
type,
t => _interfaceTypes.FirstOrDefault(
it => it.IsAssignableFrom(t)) ?? t);
var props = base.CreateProperties(typeToSerialize, memberSerialization);
// mark all props as not ignored
foreach (var prop in props)
{
prop.Ignored = false;
}
return props;
}
}
Inspired by #user3161686, here's a small modification to InterfaceContractResolver:
public class InterfaceContractResolver<TInterface> : DefaultContractResolver where TInterface : class
{
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
IList<JsonProperty> properties = base.CreateProperties(typeof(TInterface), memberSerialization);
return properties;
}
}
You can use conditional serialization. Take a look at this link. Basicly, you need to implement the IContractResolver interface, overload the ShouldSerialize method and pass your resolver to the constructor of the Json Serializer.
An alternative to [JsonIgnore] are the [DataContract] and [DataMember] attributes. If you class is tagged with [DataContract] the serializer will only process properties tagged with the [DataMember] attribute (JsonIgnore is an "opt-out" model while DataContract is "op-in").
[DataContract]
public class Thing : IThing
{
[DataMember]
public int Id { get; set; }
public string Name { get; set; }
}
The limitation of both approaches is that they must be implemented in the class, you cannot add them to the interface definition.
You can add the [JsonIgnore] annotation to ignore an attribute.
I'd like to share what we ended up doing when confronted with this task. Given the OP's interface and class...
public interface IThing
{
string Name { get; set; }
}
public class Thing : IThing
{
public int Id { get; set; }
public string Name { get; set; }
}
...we created a class that is the direct implementation of the interface...
public class DirectThing : IThing
{
public string Name { get; set; }
}
Then simply serialized our Thing instance, deserialized it as a DirectThing, then Serialized it as a DirectThing:
var thing = new Thing();
JsonConvert.SerializeObject(
JsonConvert.DeserializeObject<DirectThing>(JsonConvert.SerializeObject(thing)));
This approach can work with a long interface inheritance chain...you just need to make a direct class (DirectThing in this example) at the level of interest. No need to worry about reflection or attributes.
From a maintenance perspective, the DirectThing class is easy to maintain if you add members to IThing because the compiler will give errors if you haven't also put them in DirectThing. However, if you remove a member X from IThing and put it in Thing instead, then you'll have to remember to remove it from DirectThing or else X would be in the end result.
From a performance perspective there are three (de)serialization operations happening here instead of one, so depending on your situation you might like to evaluate the performance difference of reflector/attribute-based solutions versus this solution. In my case I was just doing this on a small scale, so I wasn't concerned about potential losses of some micro/milliseconds.
Hope that helps someone!
in addition to the answer given by #monrow you can use the default [DataContract] and [DataMember]
have a look at this
http://james.newtonking.com/archive/2009/10/23/efficient-json-with-json-net-reducing-serialized-json-size.aspx
Finally I got when it will not work...
If you want to have inside another complex object it will not be properly serialized.
So I have made version which will extract only data stored in specific assembly and for types which have the same base interface.
So it is made as .Net Core JsonContractResolver.
In addition to data extraction it solves:
a) camelCase conversion before sending data to client
b) uses top most interface from allowed scope (by assembly)
c) fixes order of fields: field from most base class will be listed first and nested object will meet this rule as well.
public class OutputJsonResolver : DefaultContractResolver
{
#region Static Members
private static readonly object syncTargets = new object();
private static readonly Dictionary<Type, IList<JsonProperty>> Targets = new Dictionary<Type, IList<JsonProperty>>();
private static readonly Assembly CommonAssembly = typeof(ICommon).Assembly;
#endregion
#region Override Members
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
if (type.Assembly != OutputJsonResolver.CommonAssembly)
return base.CreateProperties(type, memberSerialization);
IList<JsonProperty> properties;
if (OutputJsonResolver.Targets.TryGetValue(type, out properties) == false)
{
lock (OutputJsonResolver.syncTargets)
{
if (OutputJsonResolver.Targets.ContainsKey(type) == false)
{
properties = this.CreateCustomProperties(type, memberSerialization);
OutputJsonResolver.Targets[type] = properties;
}
}
}
return properties;
}
protected override string ResolvePropertyName(string propertyName)
{
return propertyName.ToCase(Casing.Camel);
}
#endregion
#region Assistants
private IList<JsonProperty> CreateCustomProperties(Type type, MemberSerialization memberSerialization)
{
// Hierarchy
IReadOnlyList<Type> types = this.GetTypes(type);
// Head
Type head = types.OrderByDescending(item => item.GetInterfaces().Length).FirstOrDefault();
// Sources
IList<JsonProperty> sources = base.CreateProperties(head, memberSerialization);
// Targets
IList<JsonProperty> targets = new List<JsonProperty>(sources.Count);
// Repository
IReadOnlyDistribution<Type, JsonProperty> repository = sources.ToDistribution(item => item.DeclaringType);
foreach (Type current in types.Reverse())
{
IReadOnlyPage<JsonProperty> page;
if (repository.TryGetValue(current, out page) == true)
targets.AddRange(page);
}
return targets;
}
private IReadOnlyList<Type> GetTypes(Type type)
{
List<Type> types = new List<Type>();
if (type.IsInterface == true)
types.Add(type);
types.AddRange(type.GetInterfaces());
return types;
}
#endregion
}
I have this object
[DataContract]
public class FilterList<T> : List<T>
{
[DataMember]
public int Total { get; set; }
}
In my controller:
public ActionResult<FilterList<MyPOCO>> GetFilteredResult(string filter)
{
var l = new FilterList<MyPOCO>();
l.Total = 123456;
// Continue to add many MyPOCO objects into the list
return l;
}
I can get back the MyPOCO list at the client side, but the l.Total is NOT serialize. May I know what I had done wrongly?
Here is a workaround , you could try to use [JsonObject] attribute . But the items will not be serialized, because a JSON container can have properties, or items -- but not both. If you want both, you will need to add a synthetic list property to hold the items.
[JsonObject] will also cause base class properties such as Capacity to be serialized, which you likely do not want. To suppress base class properties, use MemberSerialization.OptIn. Thus your final class should look something like:
[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
public class FilterList<T> : List<T>
{
[JsonProperty]
public int Total { get; set; }
[JsonProperty]
List<T> Items
{
get
{
return this.ToList();
}
set
{
if (value != null)
this.AddRange(value);
}
}
}
Result:
What is the best way to do the following:
Suppose I have a class called Person and many derived classes for specialized persons.
Suppose at the beginning of my app, I know I have to deal with a person but I won't know what kind of person it is until much later (something beyond my control so I cannot determine the Person type at the beginning).
So at the beginning I will create a Person and fill in attributes for it. Later, when I know what kind of Person it is, I would instantiate a specialized person and copy over the any saved attributes for her.
Is there a more elegant way to do this without creating two objects?
If you don't know the type of person up front, you won't be able to avoid instantiating two objects. There has to be something to contain the base Person attributes before you know the specialized person, but you can't take advantage of polymorphism without instantiating the specialized object later.
One option is to use a composition pattern, in which each specialized person contains a Person instance rather than inheriting from it. You still have to instantiate two objects, but you don't have to rewrite the code to copy over the saved attributes every time. Here's an example (C# syntax):
public interface IPerson
{
string Name { get; }
int Age { get; }
}
public class Person : IPerson
{
public string Name { get; private set; }
public int Age { get; private set; }
public Person(string name, int age)
{
Name = name;
Age = age;
}
}
public abstract class SpecialPersonBase : IPerson
{
private IPerson myPerson;
protected SpecialPersonBase(IPerson person)
{
myPerson = person;
}
public string Name { get { return myPerson.Name; } }
public int Age { get { return myPerson.Age; } }
public abstract string Greet();
}
public class Doctor : SpecialPersonBase
{
public Doctor(IPerson person) : base(person) { }
public override string Greet()
{
return "How are you feeling?";
}
}
public class Accountant : SpecialPersonBase
{
public Accountant(IPerson person) : base(person) { }
public override string Greet()
{
return "How are your finances?";
}
}
You could use the classes like this:
IPerson bob = new Person("Bob", "25");
// Do things with the generic object
// until you can determine the specific type
SpecialPerson specialBob;
if (bobIsDoctor)
{
specialBob = new Doctor(bob);
}
else if (bobisAccountant)
{
specialBob = new Accountant(bob);
}
specialBob.Greet();
I am trying to use Ninject to implement cascading injection into a class that contains an IList field. It seems that, unless I specifically specify each binding to use in the kernel.Get method, the IList property is always injected with a list of a single default object.
The following VSTest code illustrates the problem. The first test fails because the IList field contains one MyType object with Name=null. The second test passes, but I had to specifically tell Ninject what constructor arguments to use. I am using the latest build from the ninject.web.mvc project for MVC 3.
Does Ninject specifically treat IList different, or is there a better way to handle this? Note that this seems to only be a problem when using an IList. Createing a custom collection object that wraps IList works as expected in the first test.
[TestClass()]
public class NinjectTest
{
[TestMethod()]
public void ListTest_Fails_NameNullAndCountIncorrect()
{
var kernel = new Ninject.StandardKernel(new MyNinjectModule());
var target = kernel.Get<MyModel>();
var actual = target.GetList();
// Fails. Returned value is set to a list of a single object equal to default(MyType)
Assert.AreEqual(2, actual.Count());
// Fails because MyType object is initialized with a null "Name" property
Assert.AreEqual("Fred", actual.First().Name);
}
[TestMethod()]
public void ListTest_Passes_SeemsLikeUnnecessaryConfiguration()
{
var kernel = new Ninject.StandardKernel(new MyNinjectModule());
var target = kernel.Get<MyModel>(new ConstructorArgument("myGenericObject", kernel.Get<IGenericObject<MyType>>(new ConstructorArgument("myList", kernel.Get<IList<MyType>>()))));
var actual = target.GetList();
Assert.AreEqual(2, actual.Count());
Assert.AreEqual("Fred", actual.First().Name);
}
}
public class MyNinjectModule : NinjectModule
{
public override void Load()
{
Bind<IList<MyType>>().ToConstant(new List<MyType> { new MyType { Name = "Fred" }, new MyType { Name = "Bob" } });
Bind<IGenericObject<MyType>>().To<StubObject<MyType>>();
}
}
public class MyModel
{
private IGenericObject<MyType> myGenericObject;
public MyModel(IGenericObject<MyType> myGenericObject)
{
this.myGenericObject = myGenericObject;
}
public IEnumerable<MyType> GetList()
{
return myGenericObject.GetList();
}
}
public interface IGenericObject<T>
{
IList<T> GetList();
}
public class StubObject<T> : IGenericObject<T>
{
private IList<T> _myList;
public StubObject(IList<T> myList)
{
_myList = myList;
}
public IList<T> GetList()
{
return _myList;
}
}
public class MyType
{
public String Name { get; set; }
}
lists, collections and arrays are handled slightly different. For those types ninject will inject a list or array containing an instance of all bindings for the generic type. In your case the implementation type is a class which is aoutobound by default. So the list will contain one instance of that class. If you add an interface to that class and use this one the list will be empty.
Is there a way to persist an enum to the DB using NHibernate? That is have a table of both the code and the name of each value in the enum.
I want to keep the enum without an entity, but still have a foreign key (the int representation of the enum) from all other referencing entities to the enum's table.
Why are you guys over complicating this? It is really simple.
The mapping looks like this:
<property name="OrganizationType"></property>
The model property looks like this:
public virtual OrganizationTypes OrganizationType { get; set; }
The Enum looks like this:
public enum OrganizationTypes
{
NonProfit = 1,
ForProfit = 2
}
NHibernate will automatically figure it all out. Why type more than you need????
You can use the enum type directly: http://web.archive.org/web/20100225131716/http://graysmatter.codivation.com/post/Justice-Grays-NHibernate-War-Stories-Dont-Use-Int-If-You-Mean-Enum.aspx. If your underlying type is a string, it should use the string representation, if it is numeric, it will just use the numeric representation.
But your question wording sounds like you're looking for something different, not quite an enum. It seems that you want a lookup table without creating a separate entity class. I don't think this can be done without creating a separate entity class though.
An easy but not so beautiful solution:
Create an integer field with and set the mapping in the mapping file to the field.
Create a public property that uses the integer field.
private int myField;
public virtual MyEnum MyProperty
{
get { return (MyEnum)myField; }
set { myField = value; }
}
I am using NHibernate 3.2, and this works great:
type="NHibernate.Type.EnumStringType`1[[enum_full_type_name, enum_assembly]], NHibernate"
Not sure when the generic EnumStringType got added, though.
Try using a stategy pattern. Uou can then put logic into your inner classes. I use this quite alot espically when there is logic that should be contained in the "enum". For example the code below has the abstract IsReadyForSubmission() which is then implemented in each of the nested subclasses (only one shown). HTH
[Serializable]
public abstract partial class TimesheetStatus : IHasIdentity<int>
{
public static readonly TimesheetStatus NotEntered = new NotEnteredTimesheetStatus();
public static readonly TimesheetStatus Draft = new DraftTimesheetStatus();
public static readonly TimesheetStatus Submitted = new SubmittedTimesheetStatus();
//etc
public abstract int Id { get; protected set; }
public abstract string Description { get; protected set; }
public abstract bool IsReadyForSubmission();
protected class NotEnteredTimesheetStatus: TimesheetStatus
{
private const string DESCRIPTION = "NotEntered";
private const int ID = 0;
public override int Id
{
get { return ID; }
protected set { if (value != ID)throw new InvalidOperationException("ID for NotEnteredTimesheetStatus must be " + ID); }
}
public override string Description
{
get { return DESCRIPTION; }
protected set { if (value != DESCRIPTION)throw new InvalidOperationException("The description for NotEnteredTimesheetStatus must be " + DESCRIPTION); }
}
public override bool IsReadyForSubmission()
{
return false;
}
}
//etc
}