How to use DataContractSerializer with Binder

Question

Hi Team,

We are converting BinaryFormatter to DataContractSerializer in our code.

With BinaryFormatter we had used Binder property , How can we convert that with DataContractSerializer?

Sample:

var bf = new BinaryFormatter();

bf.Binder = new ClassXYZ();//ClassXYZ inherited from SerializationBinder

var dc = (Class2)bf.Deserialize(stream);

Answer 1

Hi @Deepak Rane (drane) , Welcome to Microsoft Q&A,

The Binder property in BinaryFormatter allows you to control type resolution during deserialization. However, DataContractSerializer does not directly support this feature. Try to use a custom DataContractResolver.

using System;
using System.IO;
using System.Runtime.Serialization;

public class CustomResolver : DataContractResolver
{
    public override Type ResolveName(string typeName, string typeNamespace, Type declaredType, DataContractResolver knownTypeResolver)
    {
        // Custom logic to map serialized type name to actual type
        if (typeName == "ClassXYZ" && typeNamespace == "http://yournamespace/")
        {
            return typeof(ClassXYZ); // Map serialized name to actual type
        }

        // Default resolution
        return knownTypeResolver.ResolveName(typeName, typeNamespace, declaredType, null);
    }

    public override bool TryResolveType(Type type, Type declaredType, DataContractResolver knownTypeResolver, out XmlDictionaryString typeName, out XmlDictionaryString typeNamespace)
    {
        var dictionary = new XmlDictionary();

        // Custom logic to map actual type to serialized type name
        if (type == typeof(ClassXYZ))
        {
            typeName = dictionary.Add("ClassXYZ");
            typeNamespace = dictionary.Add("http://yournamespace/");
            return true;
        }

        // Default resolution
        return knownTypeResolver.TryResolveType(type, declaredType, null, out typeName, out typeNamespace);
    }
}

[DataContract]
public class Class2
{
    [DataMember]
    public string Property { get; set; }
}

[DataContract]
public class ClassXYZ
{
    [DataMember]
    public int Value { get; set; }
}

class Program
{
    static void Main()
    {
        var stream = new MemoryStream();
        var instance = new Class2 { Property = "Test" };

        // Serialize using DataContractSerializer
        var serializer = new DataContractSerializer(typeof(Class2), null, int.MaxValue, false, true, null, new CustomResolver());
        serializer.WriteObject(stream, instance);

        stream.Position = 0;

        // Deserialize using DataContractSerializer
        var deserializer = new DataContractSerializer(typeof(Class2), null, int.MaxValue, false, true, null, new CustomResolver());
        var result = (Class2)deserializer.ReadObject(stream);

        Console.WriteLine($"Deserialized Property: {result.Property}");
    }
}

Best Regards,

Jiale

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