Convert Dictionary<string, object> To Anonymous Object?

Question

First, and to make things clearer I'll explain my scenario from the top:

I have a method which has the following signature:

public virtual void SendEmail(String from, List<String> recepients, Object model)

What I want to do is generate an anonymous object which has the properties of the model object along with the first two parameters as well. Flattening the model object into a PropertyInfo[] is very straightforward. Accordingly, I thought of creating a Dictionary which would hold the PropertyInfo's and the first two params, and then be converted into the anonymous object where the key is the name of the property and the value is the actual value of the property.

Is that possible? Any other suggestions?

Answer 1

If you really want to convert the dictionary to an object that has the items of the dictionary as properties, you can use ExpandoObject:

var dict = new Dictionary<string, object> { { "Property", "foo" } };
var eo = new ExpandoObject();
var eoColl = (ICollection<KeyValuePair<string, object>>)eo;

foreach (var kvp in dict)
{
    eoColl.Add(kvp);
}

dynamic eoDynamic = eo;

string value = eoDynamic.Property;

Answer 2

I tried to do this in one statement with a reduce function (Aggregate in Linq). The code below does the same as the accepted answer:

var dict = new Dictionary<string, object> { { "Property", "foo" } };
dynamic eo = dict.Aggregate(new ExpandoObject() as IDictionary<string, Object>,
                            (a, p) => { a.Add(p); return a; });
string value = eo.Property;

Answer 3

If you want to convert Dictionary<string, object> To Anonymous System.Object. You can use this method:

public static object FromDictToAnonymousObj<TValue>(IDictionary<string, TValue> dict)
{
    var types = new Type[dict.Count];

    for (int i = 0; i < types.Length; i++)
    {
        types[i] = typeof(TValue);
    }

    // dictionaries don't have an order, so we force an order based
    // on the Key
    var ordered = dict.OrderBy(x => x.Key).ToArray();

    string[] names = Array.ConvertAll(ordered, x => x.Key);

    Type type = AnonymousType.CreateType(types, names);

    object[] values = Array.ConvertAll(ordered, x => (object)x.Value);

    object obj = type.GetConstructor(types).Invoke(values);

    return obj;
}

like this:

var dict = new Dictionary<string, string>
{
    {"Id", "1"},
    {"Title", "My title"},
    {"Description", "Blah blah blah"},
};

object obj1 = FromDictToAnonymousObj(dict);

to obtain your object. Where AnonymousType class code is:

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading;

/// <summary>
/// The code generated should be nearly equal to the one generated by
/// csc 12.0.31101.0 when compiling with /optimize+ /debug-. The main
/// difference is in the GetHashCode() (the base init_hash used is 
/// compiler-dependant) and in the maxstack of the generated methods.
/// Note that Roslyn (at least the one present at 
/// tryroslyn.azurewebsites.net) generates different code for anonymous
/// types.
/// </summary>
public static class AnonymousType
{
    private static readonly ConcurrentDictionary<string, Type> GeneratedTypes = new ConcurrentDictionary<string, Type>();

    private static readonly AssemblyBuilder AssemblyBuilder;
    private static readonly ModuleBuilder ModuleBuilder;
    private static readonly string FileName;

    // Some objects we cache
    private static readonly CustomAttributeBuilder CompilerGeneratedAttributeBuilder = new CustomAttributeBuilder(typeof(CompilerGeneratedAttribute).GetConstructor(Type.EmptyTypes), new object[0]);
    private static readonly CustomAttributeBuilder DebuggerBrowsableAttributeBuilder = new CustomAttributeBuilder(typeof(DebuggerBrowsableAttribute).GetConstructor(new[] { typeof(DebuggerBrowsableState) }), new object[] { DebuggerBrowsableState.Never });
    private static readonly CustomAttributeBuilder DebuggerHiddenAttributeBuilder = new CustomAttributeBuilder(typeof(DebuggerHiddenAttribute).GetConstructor(Type.EmptyTypes), new object[0]);

    private static readonly ConstructorInfo ObjectCtor = typeof(object).GetConstructor(Type.EmptyTypes);
    private static readonly MethodInfo ObjectToString = typeof(object).GetMethod("ToString", BindingFlags.Instance | BindingFlags.Public, null, Type.EmptyTypes, null);

    private static readonly ConstructorInfo StringBuilderCtor = typeof(StringBuilder).GetConstructor(Type.EmptyTypes);
    private static readonly MethodInfo StringBuilderAppendString = typeof(StringBuilder).GetMethod("Append", BindingFlags.Instance | BindingFlags.Public, null, new[] { typeof(string) }, null);
    private static readonly MethodInfo StringBuilderAppendObject = typeof(StringBuilder).GetMethod("Append", BindingFlags.Instance | BindingFlags.Public, null, new[] { typeof(object) }, null);

    private static readonly Type EqualityComparer = typeof(EqualityComparer<>);
    private static readonly Type EqualityComparerGenericArgument = EqualityComparer.GetGenericArguments()[0];
    private static readonly MethodInfo EqualityComparerDefault = EqualityComparer.GetMethod("get_Default", BindingFlags.Static | BindingFlags.Public, null, Type.EmptyTypes, null);
    private static readonly MethodInfo EqualityComparerEquals = EqualityComparer.GetMethod("Equals", BindingFlags.Instance | BindingFlags.Public, null, new[] { EqualityComparerGenericArgument, EqualityComparerGenericArgument }, null);
    private static readonly MethodInfo EqualityComparerGetHashCode = EqualityComparer.GetMethod("GetHashCode", BindingFlags.Instance | BindingFlags.Public, null, new[] { EqualityComparerGenericArgument }, null);

    private static int Index = -1;

    static AnonymousType()
    {
        var assemblyName = new AssemblyName("AnonymousTypes");

        FileName = assemblyName.Name + ".dll";

        AssemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.RunAndSave);
        ModuleBuilder = AssemblyBuilder.DefineDynamicModule("AnonymousTypes", FileName);
    }

    public static void Dump()
    {
        AssemblyBuilder.Save(FileName);
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="types"></param>
    /// <param name="names"></param>
    /// <returns></returns>
    public static Type CreateType(Type[] types, string[] names)
    {
        if (types == null)
        {
            throw new ArgumentNullException("types");
        }

        if (names == null)
        {
            throw new ArgumentNullException("names");
        }

        if (types.Length != names.Length)
        {
            throw new ArgumentException("names");
        }

        // Anonymous classes are generics based. The generic classes
        // are distinguished by number of parameters and name of 
        // parameters. The specific types of the parameters are the 
        // generic arguments. We recreate this by creating a fullName
        // composed of all the property names, separated by a "|"
        string fullName = string.Join("|", names.Select(x => Escape(x)));

        Type type;

        if (!GeneratedTypes.TryGetValue(fullName, out type))
        {
            // We create only a single class at a time, through this lock
            // Note that this is a variant of the double-checked locking.
            // It is safe because we are using a thread safe class.
            lock (GeneratedTypes)
            {
                if (!GeneratedTypes.TryGetValue(fullName, out type))
                {
                    int index = Interlocked.Increment(ref Index);

                    string name = names.Length != 0 ? string.Format("<>f__AnonymousType{0}`{1}", index, names.Length) : string.Format("<>f__AnonymousType{0}", index);
                    TypeBuilder tb = ModuleBuilder.DefineType(name, TypeAttributes.AnsiClass | TypeAttributes.Class | TypeAttributes.AutoLayout | TypeAttributes.NotPublic | TypeAttributes.Sealed | TypeAttributes.BeforeFieldInit);
                    tb.SetCustomAttribute(CompilerGeneratedAttributeBuilder);

                    GenericTypeParameterBuilder[] generics = null;

                    if (names.Length != 0)
                    {
                        string[] genericNames = Array.ConvertAll(names, x => string.Format("<{0}>j__TPar", x));
                        generics = tb.DefineGenericParameters(genericNames);
                    }
                    else
                    {
                        generics = new GenericTypeParameterBuilder[0];
                    }

                    // .ctor
                    ConstructorBuilder constructor = tb.DefineConstructor(MethodAttributes.Public | MethodAttributes.HideBySig, CallingConventions.HasThis, generics);
                    constructor.SetCustomAttribute(DebuggerHiddenAttributeBuilder);
                    ILGenerator ilgeneratorConstructor = constructor.GetILGenerator();
                    ilgeneratorConstructor.Emit(OpCodes.Ldarg_0);
                    ilgeneratorConstructor.Emit(OpCodes.Call, ObjectCtor);

                    var fields = new FieldBuilder[names.Length];

                    // There are two for cycles because we want to have
                    // all the getter methods before all the other 
                    // methods
                    for (int i = 0; i < names.Length; i++)
                    {
                        // field
                        fields[i] = tb.DefineField(string.Format("<{0}>i__Field", names[i]), generics[i], FieldAttributes.Private | FieldAttributes.InitOnly);
                        fields[i].SetCustomAttribute(DebuggerBrowsableAttributeBuilder);

                        // .ctor
                        constructor.DefineParameter(i + 1, ParameterAttributes.None, names[i]);
                        ilgeneratorConstructor.Emit(OpCodes.Ldarg_0);

                        if (i == 0)
                        {
                            ilgeneratorConstructor.Emit(OpCodes.Ldarg_1);
                        }
                        else if (i == 1)
                        {
                            ilgeneratorConstructor.Emit(OpCodes.Ldarg_2);
                        }
                        else if (i == 2)
                        {
                            ilgeneratorConstructor.Emit(OpCodes.Ldarg_3);
                        }
                        else if (i < 255)
                        {
                            ilgeneratorConstructor.Emit(OpCodes.Ldarg_S, (byte)(i + 1));
                        }
                        else
                        {
                            // Ldarg uses a ushort, but the Emit only
                            // accepts short, so we use a unchecked(...),
                            // cast to short and let the CLR interpret it
                            // as ushort
                            ilgeneratorConstructor.Emit(OpCodes.Ldarg, unchecked((short)(i + 1)));
                        }

                        ilgeneratorConstructor.Emit(OpCodes.Stfld, fields[i]);

                        // getter
                        MethodBuilder getter = tb.DefineMethod(string.Format("get_{0}", names[i]), MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.SpecialName, CallingConventions.HasThis, generics[i], Type.EmptyTypes);
                        ILGenerator ilgeneratorGetter = getter.GetILGenerator();
                        ilgeneratorGetter.Emit(OpCodes.Ldarg_0);
                        ilgeneratorGetter.Emit(OpCodes.Ldfld, fields[i]);
                        ilgeneratorGetter.Emit(OpCodes.Ret);

                        PropertyBuilder property = tb.DefineProperty(names[i], PropertyAttributes.None, CallingConventions.HasThis, generics[i], Type.EmptyTypes);
                        property.SetGetMethod(getter);
                    }

                    // ToString()
                    MethodBuilder toString = tb.DefineMethod("ToString", MethodAttributes.Public | MethodAttributes.Virtual | MethodAttributes.HideBySig, CallingConventions.HasThis, typeof(string), Type.EmptyTypes);
                    toString.SetCustomAttribute(DebuggerHiddenAttributeBuilder);
                    ILGenerator ilgeneratorToString = toString.GetILGenerator();

                    ilgeneratorToString.DeclareLocal(typeof(StringBuilder));

                    ilgeneratorToString.Emit(OpCodes.Newobj, StringBuilderCtor);
                    ilgeneratorToString.Emit(OpCodes.Stloc_0);

                    // Equals
                    MethodBuilder equals = tb.DefineMethod("Equals", MethodAttributes.Public | MethodAttributes.Virtual | MethodAttributes.HideBySig, CallingConventions.HasThis, typeof(bool), new[] { typeof(object) });
                    equals.SetCustomAttribute(DebuggerHiddenAttributeBuilder);
                    equals.DefineParameter(1, ParameterAttributes.None, "value");
                    ILGenerator ilgeneratorEquals = equals.GetILGenerator();
                    ilgeneratorEquals.DeclareLocal(tb);

                    ilgeneratorEquals.Emit(OpCodes.Ldarg_1);
                    ilgeneratorEquals.Emit(OpCodes.Isinst, tb);
                    ilgeneratorEquals.Emit(OpCodes.Stloc_0);
                    ilgeneratorEquals.Emit(OpCodes.Ldloc_0);

                    Label equalsLabel = ilgeneratorEquals.DefineLabel();

                    // GetHashCode()
                    MethodBuilder getHashCode = tb.DefineMethod("GetHashCode", MethodAttributes.Public | MethodAttributes.Virtual | MethodAttributes.HideBySig, CallingConventions.HasThis, typeof(int), Type.EmptyTypes);
                    getHashCode.SetCustomAttribute(DebuggerHiddenAttributeBuilder);
                    ILGenerator ilgeneratorGetHashCode = getHashCode.GetILGenerator();
                    ilgeneratorGetHashCode.DeclareLocal(typeof(int));

                    if (names.Length == 0)
                    {
                        ilgeneratorGetHashCode.Emit(OpCodes.Ldc_I4_0);
                    }
                    else
                    {
                        // As done by Roslyn
                        // Note that initHash can vary, because
                        // string.GetHashCode() isn't "stable" for 
                        // different compilation of the code
                        int initHash = 0;

                        for (int i = 0; i < names.Length; i++)
                        {
                            initHash = unchecked(initHash * (-1521134295) + fields[i].Name.GetHashCode());
                        }

                        // Note that the CSC seems to generate a 
                        // different seed for every anonymous class
                        ilgeneratorGetHashCode.Emit(OpCodes.Ldc_I4, initHash);
                    }

                    for (int i = 0; i < names.Length; i++)
                    {
                        // Equals()
                        Type equalityComparerT = EqualityComparer.MakeGenericType(generics[i]);
                        MethodInfo equalityComparerTDefault = TypeBuilder.GetMethod(equalityComparerT, EqualityComparerDefault);
                        MethodInfo equalityComparerTEquals = TypeBuilder.GetMethod(equalityComparerT, EqualityComparerEquals);

                        ilgeneratorEquals.Emit(OpCodes.Brfalse_S, equalsLabel);
                        ilgeneratorEquals.Emit(OpCodes.Call, equalityComparerTDefault);
                        ilgeneratorEquals.Emit(OpCodes.Ldarg_0);
                        ilgeneratorEquals.Emit(OpCodes.Ldfld, fields[i]);
                        ilgeneratorEquals.Emit(OpCodes.Ldloc_0);
                        ilgeneratorEquals.Emit(OpCodes.Ldfld, fields[i]);
                        ilgeneratorEquals.Emit(OpCodes.Callvirt, equalityComparerTEquals);

                        // GetHashCode();
                        MethodInfo EqualityComparerTGetHashCode = TypeBuilder.GetMethod(equalityComparerT, EqualityComparerGetHashCode);

                        ilgeneratorGetHashCode.Emit(OpCodes.Stloc_0);
                        ilgeneratorGetHashCode.Emit(OpCodes.Ldc_I4, -1521134295);
                        ilgeneratorGetHashCode.Emit(OpCodes.Ldloc_0);
                        ilgeneratorGetHashCode.Emit(OpCodes.Mul);
                        ilgeneratorGetHashCode.Emit(OpCodes.Call, EqualityComparerDefault);
                        ilgeneratorGetHashCode.Emit(OpCodes.Ldarg_0);
                        ilgeneratorGetHashCode.Emit(OpCodes.Ldfld, fields[i]);
                        ilgeneratorGetHashCode.Emit(OpCodes.Callvirt, EqualityComparerGetHashCode);
                        ilgeneratorGetHashCode.Emit(OpCodes.Add);

                        // ToString()
                        ilgeneratorToString.Emit(OpCodes.Ldloc_0);
                        ilgeneratorToString.Emit(OpCodes.Ldstr, i == 0 ? string.Format("{{ {0} = ", names[i]) : string.Format(", {0} = ", names[i]));
                        ilgeneratorToString.Emit(OpCodes.Callvirt, StringBuilderAppendString);
                        ilgeneratorToString.Emit(OpCodes.Pop);
                        ilgeneratorToString.Emit(OpCodes.Ldloc_0);
                        ilgeneratorToString.Emit(OpCodes.Ldarg_0);
                        ilgeneratorToString.Emit(OpCodes.Ldfld, fields[i]);
                        ilgeneratorToString.Emit(OpCodes.Box, generics[i]);
                        ilgeneratorToString.Emit(OpCodes.Callvirt, StringBuilderAppendObject);
                        ilgeneratorToString.Emit(OpCodes.Pop);
                    }

                    // .ctor
                    ilgeneratorConstructor.Emit(OpCodes.Ret);

                    // Equals()
                    if (names.Length == 0)
                    {
                        ilgeneratorEquals.Emit(OpCodes.Ldnull);
                        ilgeneratorEquals.Emit(OpCodes.Ceq);
                        ilgeneratorEquals.Emit(OpCodes.Ldc_I4_0);
                        ilgeneratorEquals.Emit(OpCodes.Ceq);
                    }
                    else
                    {
                        ilgeneratorEquals.Emit(OpCodes.Ret);
                        ilgeneratorEquals.MarkLabel(equalsLabel);
                        ilgeneratorEquals.Emit(OpCodes.Ldc_I4_0);
                    }

                    ilgeneratorEquals.Emit(OpCodes.Ret);

                    // GetHashCode()
                    ilgeneratorGetHashCode.Emit(OpCodes.Stloc_0);
                    ilgeneratorGetHashCode.Emit(OpCodes.Ldloc_0);
                    ilgeneratorGetHashCode.Emit(OpCodes.Ret);

                    // ToString()
                    ilgeneratorToString.Emit(OpCodes.Ldloc_0);
                    ilgeneratorToString.Emit(OpCodes.Ldstr, names.Length == 0 ? "{ }" : " }");
                    ilgeneratorToString.Emit(OpCodes.Callvirt, StringBuilderAppendString);
                    ilgeneratorToString.Emit(OpCodes.Pop);
                    ilgeneratorToString.Emit(OpCodes.Ldloc_0);
                    ilgeneratorToString.Emit(OpCodes.Callvirt, ObjectToString);
                    ilgeneratorToString.Emit(OpCodes.Ret);

                    type = tb.CreateType();

                    type = GeneratedTypes.GetOrAdd(fullName, type);
                }
            }
        }

        if (types.Length != 0)
        {
            type = type.MakeGenericType(types);
        }

        return type;
    }

    private static string Escape(string str)
    {
        // We escape the \ with \\, so that we can safely escape the
        // "|" (that we use as a separator) with "\|"
        str = str.Replace(@"\", @"\\");
        str = str.Replace(@"|", @"\|");
        return str;
    }
}

Reference: https://stackoverflow.com/a/29428640/2073920