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@leandromoh
Created September 19, 2021 07:00
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Spread object in C#
using System;
using System.Buffers;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;
using System.Text.Json;
using static MoreLinq.Extensions.DistinctByExtension;
// adapted from https://gist.github.com/AlbertoMonteiro/f6aa8c92a7d93c9b32b4c2ab19a67def
var cliente = new Brazilian { Nome = "Bob", Id = Guid.Parse("c301f874-007f-4b40-a191-56216e6ba98c") };
var cliente2 = new American { Nome = "Leandro", Id = "A7D8" };
var endereco = new Endereco { Logradouro = "Rua Mole", Numero = 123 };
var opa = cliente.Spread(cliente2, endereco, new { UsaGitHub = true });
// { "Nome":"Leandro","Logradouro":"Rua Mole","Numero":123,"UsaGitHub":true}
Console.WriteLine(JsonSerializer.Serialize(opa));
// { "Id":"c301f874-007f-4b40-a191-56216e6ba98c"}
Console.WriteLine(JsonSerializer.Serialize(opa as IBR));
// { "Id":"A7D8"}
Console.WriteLine(JsonSerializer.Serialize(opa as IUSA));
public interface IUSA
{
public string Id { get; set; }
}
public class American : IUSA
{
public string Id { get; set; }
public string Nome { get; set; }
}
public interface IBR
{
public Guid Id { get; set; }
}
public class Brazilian : IBR
{
public Guid Id { get; set; }
public string Nome { get; set; }
}
class Endereco
{
public string Logradouro { get; set; }
public int Numero { get; set; }
}
public static class Extensions
{
static Extensions()
{
var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("AssemblyX"), AssemblyBuilderAccess.RunAndCollect);
ModuleBuilder = assemblyBuilder.DefineDynamicModule("MainModule");
}
public static dynamic Spread(this object obj, params object[] anotherObject)
{
var allobjs = anotherObject.Prepend(obj);
var _base = allobjs.SelectMany(x => x.GetType().GetInterfaces()).ToArray();
var interfaces = allobjs.SelectMany(o => o.GetType().GetInterfaces(), (o, i) => (o, i));
var propsInter = interfaces.SelectMany(x => x.i.GetProperties(), (x, p) => (x.o, p)).Reverse().DistinctBy(x => x.p).ToArray();
var propertiesNotInterface = allobjs
.SelectMany(o => o.GetType().GetProperties(), (o, p) => (o: o, p: p))
.Where(x =>
{
var result = _base.Any(i => i.IsAssignableFrom(x.p.DeclaringType) && i.GetProperty(x.p.Name) != null);
return result is false;
})
.ToArray();
var all = propsInter
.Concat(propertiesNotInterface).Select(x => x.p);
var objType = CreateClass(_base, all);
var finalObj = Activator.CreateInstance(objType);
var none = propertiesNotInterface
.ToDictionary(t => (t.p.DeclaringType, t.p), t => t.p.GetValue(t.o));
var fromInte = propsInter
.ToDictionary(t => (t.p.DeclaringType, t.p.GetSetMethod()), t => t.p.GetValue(t.o));
foreach (var prop in none)
{
objType.GetProperty(prop.Key.p.Name).SetValue(finalObj, prop.Value);
}
foreach (var inter in _base)
{
InterfaceMapping map = objType.GetInterfaceMap(inter);
for (int i = 0; i < map.InterfaceMethods.Length; i++)
{
MethodInfo ifaceMethod = map.InterfaceMethods[i];
MethodInfo targetMethod = map.TargetMethods[i];
if (fromInte.TryGetValue((inter, ifaceMethod), out var value))
{
targetMethod.Invoke(finalObj, new[] { value });
}
}
}
return finalObj;
}
const MethodAttributes METHOD_ATTRIBUTES = MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;
private static ModuleBuilder ModuleBuilder;
internal static Type CreateClass(Type[] _base, IEnumerable<PropertyInfo> parameters)
{
var typeBuilder = ModuleBuilder.DefineType(Guid.NewGuid().ToString(), TypeAttributes.Public | TypeAttributes.Class | TypeAttributes.AutoClass | TypeAttributes.AnsiClass | TypeAttributes.BeforeFieldInit | TypeAttributes.AutoLayout, null, interfaces: _base);
typeBuilder.DefineDefaultConstructor(MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName);
foreach (var parameter in parameters)
CreateProperty(typeBuilder, parameter);
var type = typeBuilder.CreateTypeInfo().AsType();
return type;
}
private static PropertyBuilder CreateProperty(TypeBuilder typeBuilder, PropertyInfo prop)
{
var fieldBuilder = typeBuilder.DefineField($"<{prop.DeclaringType.Name}>" + prop.Name, prop.PropertyType, FieldAttributes.Private);
var propBuilder = typeBuilder.DefineProperty(prop.Name, PropertyAttributes.HasDefault, prop.PropertyType, null);
propBuilder.SetGetMethod(DefineGet(typeBuilder, fieldBuilder, propBuilder, prop.GetGetMethod()));
propBuilder.SetSetMethod(DefineSet(typeBuilder, fieldBuilder, propBuilder, prop.GetSetMethod()));
return propBuilder;
}
private static MethodBuilder DefineSet(TypeBuilder typeBuilder, FieldBuilder fieldBuilder, PropertyBuilder propBuilder, MethodInfo m)
=> DefineMethod(typeBuilder, $"set_{propBuilder.Name}", null, new[] { propBuilder.PropertyType }, m, il =>
{
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Stfld, fieldBuilder);
il.Emit(OpCodes.Ret);
});
private static MethodBuilder DefineGet(TypeBuilder typeBuilder, FieldBuilder fieldBuilder, PropertyBuilder propBuilder, MethodInfo m)
=> DefineMethod(typeBuilder, $"get_{propBuilder.Name}", propBuilder.PropertyType, Type.EmptyTypes, m, il =>
{
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldfld, fieldBuilder);
il.Emit(OpCodes.Ret);
});
private static MethodBuilder DefineMethod(TypeBuilder typeBuilder, string methodName, Type propertyType, Type[] parameterTypes, MethodInfo m, Action<ILGenerator> bodyWriter)
{
var m2 = m?.ReflectedType?.IsInterface is true
? m.ReflectedType.GetMethod(m.Name)
: null;
var attr = m2 is null
? METHOD_ATTRIBUTES
: MethodAttributes.Private | MethodAttributes.Final | MethodAttributes.HideBySig | MethodAttributes.SpecialName | MethodAttributes.NewSlot | MethodAttributes.Virtual;
var methodBuilder = typeBuilder.DefineMethod(methodName, attr, propertyType, parameterTypes);
bodyWriter(methodBuilder.GetILGenerator());
if (m2 != null)
{
typeBuilder.DefineMethodOverride(methodBuilder, m2);
}
return methodBuilder;
}
}
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