Develop Reference

How can I create new object based on another one?

I have some not useful object with, let's say, 30 properties. Half of them are useful for me, so I want to create new useful object with only properties I need so the rest doesn't take space in object visualizers. I don't want to define new class and type them down. I want something like
var list = new List<SomeType> { usefulProp1, usefulProp2, ... };
var usefulObject = new NewItem(notUsefulObject, list);
where SomeType is not string (list doesn't contain property names).

if its something permanent then doing it properly would be to create a class that inherits from your base class and populate only the properties that you need.
public UsefulObject : NotUsefulObject
{
public int MyProperty
{
get
{
return base.MyProperty; // this is arbitrary you can do it however you want.
}
set
{
MyProperty = value;
}
}
}
Then you can use your reuse your useful object however you want.
var list = new List<UsefulObject>();

var list = new List<Expression<Func<object>>> { () => notUsefulObject.usefulProp1, () => notUsefulObject.usefulProp2... };
var nm = new AssemblyName("MyDynamicAssembly");
TypeBuilder tb = Thread.GetDomain().DefineDynamicAssembly(nm, AssemblyBuilderAccess.RunAndSave).DefineDynamicModule(nm.Name, nm.Name + ".dll").DefineType("NewItem", TypeAttributes.Public);
const MethodAttributes GetSetAttr = MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;
foreach (Expression b in list.Select(x => x.Body))
{
MemberInfo mi = ((MemberExpression)b).Member;
Type t = b.Type;
FieldBuilder fb = tb.DefineField(mi.Name.ToLower(), t, FieldAttributes.Private);
PropertyBuilder pb = tb.DefineProperty(mi.Name, PropertyAttributes.HasDefault, t, null);
MethodBuilder getBld = tb.DefineMethod("get_" + mi.Name, GetSetAttr, t, Type.EmptyTypes);
ILGenerator getGen = getBld.GetILGenerator();
getGen.Emit(OpCodes.Ldarg_0);
getGen.Emit(OpCodes.Ldfld, fb);
getGen.Emit(OpCodes.Ret);
MethodBuilder setBld = tb.DefineMethod("set_" + mi.Name, GetSetAttr, null, new[] { t });
ILGenerator setGen = setBld.GetILGenerator();
setGen.Emit(OpCodes.Ldarg_0);
setGen.Emit(OpCodes.Ldarg_1);
setGen.Emit(OpCodes.Stfld, fb);
setGen.Emit(OpCodes.Ret);
pb.SetGetMethod(getBld);
pb.SetSetMethod(setBld);
}
object usefulObject = Activator.CreateInstance(tb.CreateType());

Because you said this problem was specific to object visualizers, the best solution is to make a Debugger Type Proxy for the class which can be used as a proxy.
[DebuggerTypeProxy(typeof(SomeTypeDebugView))]
public class SomeType
{
public string Foo { get; set; }
public string Bar { get; set; }
internal class SomeTypeDebugView
{
private SomeType _someType;
public SomeTypeDebugView(SomeType someType)
{
_someType = someType;
}
public string Foo { get { return _someType.Foo; } }
}
}
class Program
{
static void Main()
{
var someType = new SomeType();
someType.Foo = "foo";
someType.Bar = "bar";
Debugger.Break();
}
}
This will cause Bar to be hidden in the debug visualizer by default unless you choose to view the "Raw Type"
If you are looking for a more one time debugging type you can use annonamous types to create the new type you need in the watch window, for example his is new {Foo = someType.Foo, Bar = someType.Bar }
This also could be used with LINQ to perform the select over a IEnumerable, here for example is someTypeList.Select(x=> new {Foo = x.Foo, Bar = x.Bar})

Dynamically creating properties in C# for use with XmlSerializer

I have an API that accepts xml messages. Suppose I have obtained object Thing from this API which looks like this:
<Thing shape="circle" color="red"/>
and is mapped to:
[XmlRoot("Thing")]
public class Thing {
[XmlAttribute("shape")]
public string Shape { get; set; }
[XmlAttribute("color")]
public string Color { get; set; }
}
Now I want to update this object so that eg. color is green. The API requires me to send it in the following format:
<Thing color="green" o_color="red"/>
Is there a way to generate o_* properties on the fly? So that when they are set outside of constructor their old value is stored in some generated property that XmlSerializer maps to o_? I know I could simply create those properties manually, but for bigger objects its a tedious work. I've tried to do that with Castle's Dynamic Proxy, which I already use in the project, but it seems it just can't add properties like that (or I haven't found out how to do that)

You have a couple of issues that need to be solved here. The fist is you must maintain state in each of your serialized objects that will tell you if a property has been altered, and what its original value is. Then your second problem is you need to build a new object dynamically based on this maintained state. With the implementation I provide you will need to determine if it meets your performance needs as it is doing a lot of Reflection. You will also have to weight its complexity with other solutions. The advantage I see with this solution is not having to maintain two very similar object.
!! Important !! This code is not Production ready. I have left a few todos in the code that need to be flushed out.
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Reflection.Emit;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Serialization;
namespace ConsoleApplication1
{
public abstract class PropertyStateTracker
{
private class PropertyDetails
{
public object CurrentValue { get; set; }
public bool HasChanged { get; set; }
public object OriginalValue { get; set; }
}
private readonly Dictionary<string, PropertyDetails> propertyState =
new Dictionary<string, PropertyDetails>();
protected TProperty Get<TProperty>(Expression<Func<TProperty>> propertySelector)
{
string name = GetNameFromExpression(propertySelector);
PropertyDetails data;
if (!propertyState.TryGetValue(name, out data))
{
Set(propertySelector, default(TProperty));
return default(TProperty);
}
return (TProperty)data.CurrentValue;
}
protected void Set<TProperty>(Expression<Func<TProperty>> propertySelector, TProperty value)
{
string name = GetNameFromExpression(propertySelector);
PropertyDetails data;
if (!propertyState.TryGetValue(name, out data))
{
data = new PropertyDetails() { OriginalValue = value, CurrentValue = value, HasChanged = false };
propertyState[name] = data;
}
else
{
data.CurrentValue = value;
data.HasChanged = true;
}
}
[XmlIgnore]
public IEnumerable<string> ChangedProperties
{
get
{
foreach (var property in propertyState)
{
if (property.Value.HasChanged)
{
yield return property.Key;
}
}
}
}
public bool HasChanged<TProperty>(Expression<Func<TProperty>> propertySelector)
{
string name = GetNameFromExpression(propertySelector);
return HasChanged(name);
}
public bool HasChanged(string propertyName)
{
EnsurePropertyExists(propertyName);
PropertyDetails data;
if (!propertyState.TryGetValue(propertyName, out data))
{
return false;
}
return data.HasChanged;
}
public TProperty GetOriginalValue<TProperty>(Expression<Func<TProperty>> propertySelector)
{
string name = GetNameFromExpression(propertySelector);
return (TProperty)GetOriginalValue(name);
}
public object GetOriginalValue(string propertyName)
{
EnsurePropertyExists(propertyName);
PropertyDetails data;
if (!propertyState.TryGetValue(propertyName, out data))
{
return GetDefaultValue(GetPropertyInfo(propertyName).PropertyType);
}
return data.OriginalValue;
}
public TProperty GetCurrentValue<TProperty>(Expression<Func<TProperty>> propertySelector)
{
string name = GetNameFromExpression(propertySelector);
return (TProperty)GetCurrentValue(name);
}
public object GetCurrentValue(string propertyName)
{
EnsurePropertyExists(propertyName);
PropertyDetails data;
if (!propertyState.TryGetValue(propertyName, out data))
{
return GetDefaultValue(GetPropertyInfo(propertyName).PropertyType);
}
return data.CurrentValue;
}
public void Reset()
{
foreach (var property in propertyState)
{
property.Value.OriginalValue = property.Value.CurrentValue;
property.Value.HasChanged = false;
}
}
private void EnsurePropertyExists(string propertyName)
{
PropertyInfo property = GetPropertyInfo(propertyName);
if (property == null)
{
throw new ArgumentException(string.Format("A property named '{0}' was not found for type '{1}'",
propertyName, this.GetType().Name));
}
}
private PropertyInfo GetPropertyInfo(string propertyName)
{
Type type = this.GetType();
var property = type.GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);
return property;
}
private static object GetDefaultValue(Type t)
{
if (t.IsValueType)
return Activator.CreateInstance(t);
return null;
}
private static string GetNameFromExpression<TMember>(Expression<Func<TMember>> lambda)
{
// check to make sure a non-null lambda was provided.
if (lambda == null)
{
throw new ArgumentNullException("lambda");
}
Expression expression = lambda.Body;
// is the expression's body a unary expression.
var unaryExpression = expression as UnaryExpression;
if (unaryExpression != null && unaryExpression.NodeType == ExpressionType.Convert)
{
expression = unaryExpression.Operand;
}
// is the expression's body a parameter expression.
var parameterExpression = expression as ParameterExpression;
if (parameterExpression != null)
{
return parameterExpression.Name;
}
// is the expression's body a member expression.
var memberExpression = expression as MemberExpression;
if (memberExpression != null)
{
return memberExpression.Member.Name;
}
// is the expression's body a method call expression.
var methodCallExpression = expression as MethodCallExpression;
if (methodCallExpression != null)
{
return methodCallExpression.Method.Name;
}
// unable to derive name. throw an exception.
throw new Exception(
string.Format("Failed to derive name from expression '{0}'",
expression));
}
}
[XmlRoot("Thing")]
public class Thing : PropertyStateTracker
{
[XmlAttribute("shape")]
public string Shape
{
get { return Get(() => Shape); }
set { Set(() => Shape, value); }
}
[XmlAttribute("color")]
public string Color
{
get { return Get(() => Color); }
set { Set(() => Color, value); }
}
}
class Program
{
private static long count = 0;
static void Main(string[] args)
{
Thing thingInstance;
System.Xml.Serialization.XmlSerializer serializer = new XmlSerializer(typeof(Thing));
string rawData = "<Thing shape=\"circle\" color=\"red\"/>";
using (System.IO.StringReader reader = new System.IO.StringReader(rawData))
{
thingInstance = (Thing)serializer.Deserialize(reader);
}
thingInstance.Color = "green";
// these two variables should be reused every time a new proxy is created. you dont want too many dynamic assemblies.
var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("DynamicThingAssembly"), AssemblyBuilderAccess.Run);
var moduleBuilder = assemblyBuilder.DefineDynamicModule("DynamicThingModule");
// TODO: need to figure out a way to reuse the proxyTypes being generated or you will have a
// memory leak. the type is unique based on the properties that have been modified, so you should be able to use
// the state stored inside of thingInstance to figure this out. I leave this up to you to implement.
Type proxyType = CreateProxy(moduleBuilder, thingInstance);
var proxy = Activator.CreateInstance(proxyType);
foreach (var propertyName in thingInstance.ChangedProperties)
{
proxyType.GetProperty(propertyName, BindingFlags.Instance | BindingFlags.Public | BindingFlags.IgnoreCase)
.SetValue(proxy, thingInstance.GetCurrentValue(propertyName));
proxyType.GetProperty("O_" + propertyName, BindingFlags.Instance | BindingFlags.Public | BindingFlags.IgnoreCase)
.SetValue(proxy, thingInstance.GetOriginalValue(propertyName));
}
// Important this XmlSerializer should be cached, otherwise you will have a memory leak in your program.
System.Xml.Serialization.XmlSerializer serializer2 = new XmlSerializer(proxyType, new XmlRootAttribute("Thing"));
StringBuilder sb = new StringBuilder();
using (System.IO.StringWriter writer = new System.IO.StringWriter(sb))
{
serializer2.Serialize(writer, proxy);
}
Console.Write(sb.ToString());
}
private static Type CreateProxy(ModuleBuilder moduleBuilder, Thing thing)
{
var typeName = "DynamicType" + System.Threading.Interlocked.Increment(ref count).ToString("X5");
TypeBuilder typeBuilder = moduleBuilder.DefineType(typeName, TypeAttributes.Public);
Type t = typeof(Thing);
foreach (var propertyName in thing.ChangedProperties)
{
var propertyInfo = t.GetProperty(propertyName,
BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);
CreateProperty(typeBuilder, propertyInfo.Name, propertyInfo.PropertyType);
CreateProperty(typeBuilder, "O_" + propertyInfo.Name, propertyInfo.PropertyType);
}
return typeBuilder.CreateType();
}
private static void CreateProperty(TypeBuilder typeBuilder, string propertyName, Type propertyType)
{
var fieldBuilder = typeBuilder.DefineField("_" + propertyName, propertyType, FieldAttributes.Private);
// The last argument of DefineProperty is null, because the
// property has no parameters. (If you don't specify null, you must
// specify an array of Type objects. For a parameterless property,
// use an array with no elements: new Type[] {})
var propertyBuilder = typeBuilder.DefineProperty(
propertyName, PropertyAttributes.HasDefault, propertyType, null);
var attributeConstructor = typeof(XmlAttributeAttribute).GetConstructor(new Type[] { typeof(string) });
propertyBuilder.SetCustomAttribute(
new CustomAttributeBuilder(
attributeConstructor,
new object[] { propertyName.ToLower() }));
// The property set and property get methods require a special
// set of attributes.
MethodAttributes getSetAttr =
MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;
MethodBuilder getPropertyMethodBuilder =
typeBuilder.DefineMethod("get_" + propertyName,
getSetAttr,
propertyType,
Type.EmptyTypes);
// Create the get methods body.
ILGenerator getPropertyMethodILGenerator = getPropertyMethodBuilder.GetILGenerator();
getPropertyMethodILGenerator.Emit(OpCodes.Ldarg_0);
getPropertyMethodILGenerator.Emit(OpCodes.Ldfld, fieldBuilder);
getPropertyMethodILGenerator.Emit(OpCodes.Ret);
// Define the "set" accessor method for CustomerName.
MethodBuilder setPropertyMethodBuilder =
typeBuilder.DefineMethod("set_" + propertyName,
getSetAttr,
null,
new Type[] { propertyType });
// Create the set methods body.
ILGenerator setPropertyMethodILGenerator = setPropertyMethodBuilder.GetILGenerator();
setPropertyMethodILGenerator.Emit(OpCodes.Ldarg_0);
setPropertyMethodILGenerator.Emit(OpCodes.Ldarg_1);
setPropertyMethodILGenerator.Emit(OpCodes.Stfld, fieldBuilder);
setPropertyMethodILGenerator.Emit(OpCodes.Ret);
// Last, we must map the two methods created above to our PropertyBuilder to
// their corresponding behaviors, "get" and "set" respectively.
propertyBuilder.SetGetMethod(getPropertyMethodBuilder);
propertyBuilder.SetSetMethod(setPropertyMethodBuilder);
}
}
}

How do you like this approach?
Thing thing;
var xs = new XmlSerializer(typeof(Thing));
thing = (Thing)xs.Deserialize(inputStream);
// Stored the old value in the property that will not be used.
thing.Shape = thing.Color;
thing.Color = "green"; // set new value
// Rename unused Shape property to o_color
var attributes = new XmlAttributes { XmlAttribute = new XmlAttributeAttribute("o_color") };
var overrides = new XmlAttributeOverrides();
overrides.Add(typeof(Thing), "Shape", attributes);
xs = new XmlSerializer(typeof(Thing), overrides);
xs.Serialize(outputStream, thing);
The Color property is used for its intended purpose: to store the new color value.
While the Shape property that is not returned in your example back, we use for the previous color value are pre-renamed it.
Of course, this is only work in this exceptional case: the data types match.

How do I convert from dynamic object to specified Type?

Having a model of type Dictionary<string,dynamic> and would like to convert it to Dictionary<string, MyType1> or Dictionary<string, MyOtherType>!
I've tried
var converted = (Dictionary<string,MyType1>)model
without success tried
IConvertible iConv = model; var converted = iConv.ToType(typeof(MyOtherType), null);
too but it doesn't work
Exception: Cannot convert system.object to type x
How do I convert from runtime type (dynamic) to a well known Type?

There is no built-in conversion from one dictionary type to another dictionary type. However, using Enumerable.ToDictionary, you can easily create a new dictionary from any other data structure.
In your particular example, you can use it as
var converted = model.ToDictionary(kv => kv.Key, kv => (MyType1) kv.Value);
Of course this will throw an exception if your values aren't actually of type MyType1. If they aren't, then instead of (MyType1) kv.Value, call some custom conversion function at that point.

The following little demo works for simple types:
MapDynamicToDictionary test shows turning the dynamic to a dictionary.
MapDictionaryToType shows converting the dictionary to a type T.
You could improve on this by doing checks for types or using as etc.
public class Test
{
[Fact]
public void MapDynamicToDictionary()
{
dynamic d = new { Nr = 1, Name = "Devon" };
var dictionary = TurnObjectIntoDictionary(d);
Assert.Equal(2, dictionary.Keys.Count);
}
[Fact]
public void MapDictionaryToType()
{
dynamic d = new { Nr = 1, Name = "Devon" };
var dictionary = TurnObjectIntoDictionary(d);
var instance = new MyType();
Map(dictionary, instance);
Assert.Equal(instance.Nr, 1);
Assert.Equal(instance.Name, "Devon");
}
public static void Map<T>(IDictionary<string, object> dictionary, T instance)
{
var attr = BindingFlags.Public | BindingFlags.Instance;
foreach (var prop in instance.GetType().GetProperties(attr))
{
if (prop.CanWrite)
{
if(dictionary.ContainsKey(prop.Name))
{
var v = Convert.ChangeType(dictionary[prop.Name], prop.PropertyType);
prop.SetValue(instance, v); }
}
}
}
public static IDictionary<string, object> TurnObjectIntoDictionary(object data)
{
var attr = BindingFlags.Public | BindingFlags.Instance;
var dict = new Dictionary<string, object>();
foreach (var prop in data.GetType().GetProperties(attr))
{
if (prop.CanRead)
{
dict.Add(prop.Name, prop.GetValue(data, null));
}
}
return dict;
}
}
class MyType
{
public int Nr { get; set; }
public string Name { get; set; }
}
Could use TypeConverter to handle more complex examples. Nice example here: http://putridparrot.com/blog/type-conversions-in-c/

I would put a static constructor on your well known type, which accepts dynamic, and build the well known type from that. e.g.
public class SomeType
{
public static SomeType FromDynamic(dynamic arg)
{
return new SomeType
{
SomeProperty = arg.SomeProp
}
}
public int SomeProperty {get; set; }
}
Then you'd just have to iterate over your Dictionary<string,dynamic> and build up the new object like:
var dictionary = new Dictionary<string, SomeType>();
foreach(var item in model)
{
dictionary.Add(item.Key, SomeType.FromDynamic(item.Value));
}
Or borrowing from #hvd:
var converted = model.ToDictionary(kv => kv.Key, kv => SomeType.FromDynamic(kv.Value));

How can I generate this property implementation using Expressions instead of emitting IL?

I'm trying to generate classes at runtime that implement property getters with a body that calls a method on the generated class's base class. Here's an example of a simple interface, along with a hand-written implementation that I'm trying to duplicate and the base class.
public interface IGenerated : IBase { decimal Property1 { get; } }
public class GeneratedByHand : ImplBase<IGenerated> {
public decimal Property1 { get { return Get(s => s.Property1); } }
}
public interface IBase { string _KeyPrefix { get; set; } }
public abstract class ImplBase<T> : IBase
where T : IBase
{
public virtual string _KeyPrefix { get; set; }
protected virtual TResult Get<TResult>(Expression<Func<T, TResult>> property) {
return GetValue<TResult>(GetPropertyName(property));
}
private string GetPropertyName<TResult>(Expression<Func<T, TResult>> property) {
return ""; // reflection stuff to get name from property expression goes here
}
private TResult GetValue<TResult>(string keyPart) {
return default(TResult); // does something like: return ReallyGetValue<TResult>(_KeyPrefix + keyPart);
}
}
I have a working implementation of the generator that emits IL to build the method, but if I can do it with Expressions I think that will be easier to expand and maintain. I will need to look for custom attributes on the property definitions and use that to call different method overloads on the base class in the property implementations.
Here's where I've gotten building an expression for the property get implementation. What I don't really understand is building the Call expression, if I'm setting it up correctly to do the equivalent of this.Get() or base.Get(). Right now it throws a System.ArgumentException : Invalid argument value Parameter name: method at CompileToMethod
public void CreateExpressionForGetMethod(MethodBuilder getBuilder, Type interfaceType, Type baseType, PropertyInfo property, MethodInfo getMethod)
{
var settingsParam = Expression.Parameter(interfaceType, "s");
var propGetterExpr = Expression.Property(settingsParam, property);
var propGetterExprFuncType = typeof(Func<,>).MakeGenericType(interfaceType, property.PropertyType);
var propGetterLambda = Expression.Lambda(propGetterExprFuncType, propGetterExpr, settingsParam);
var baseGetMethodInfo =
baseType.GetMethods(BindingFlags.Instance | BindingFlags.NonPublic)
.Where(m => {
var parameters = m.GetParameters();
return m.Name == "Get" &&
parameters != null && parameters.Count() == 1 && parameters[0].ParameterType != typeof(string);
})
.First().MakeGenericMethod(property.PropertyType);
var getExprType = typeof(Expression<>).MakeGenericType(propGetterExprFuncType);
var getExprParam = Expression.Parameter(getExprType, "expression");
var getCallExpr = Expression.Call(Expression.Parameter(baseType, "inst"), baseGetMethodInfo, propGetterLambda);
var getFuncType = typeof(Func<,>).MakeGenericType(getExprType, property.PropertyType);
var propLambda = Expression.Lambda(getFuncType, getCallExpr, getExprParam);
propLambda.CompileToMethod(getBuilder);
}
I'm not really sure where to go from here. I've tried a few other variations of arguments to Expression.Call, but everything else had Call throwing exceptions for the parameters being the wrong types.
Here's a buildable version of all the sample code I'm working with, including the working IL emitter:
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Reflection.Emit;
using NUnit.Framework;
namespace ExpressionGenerationTest
{
[TestFixture]
public class UnitTests
{
[Test]
public void CreateAndSaveAssembly()
{
var implGenerator = new ImplBuilder();
var generatedType = implGenerator.CreateImplementation(typeof(IGenerated));
implGenerator.SaveAssembly();
}
}
public interface IBase { string _KeyPrefix { get; set; } }
public abstract class ImplBase<T> : IBase
where T : IBase
{
public virtual string _KeyPrefix { get; set; }
protected virtual TResult Get<TResult>(Expression<Func<T, TResult>> property) { return GetValue<TResult>(GetPropertyName(property)); }
private string GetPropertyName<TResult>(Expression<Func<T, TResult>> property) { return ""; } // reflection stuff to get name from property expression goes here
private TResult GetValue<TResult>(string keyPart) { return default(TResult); } // does something like: return ReallyGetValue(_KeyPrefix + keyPart);
}
public interface IGenerated : IBase { decimal Property1 { get; } }
public class GeneratedByHand : ImplBase<IGenerated> { public decimal Property1 { get { return Get(s => s.Property1); } } }
public class ImplBuilder
{
private const string _assemblyNameBase = "ExpressionGenerationTest.Impl";
public static ImplBuilder Default { get { return _default.Value; } }
private static readonly Lazy<ImplBuilder> _default = new Lazy<ImplBuilder>(() => new ImplBuilder());
private ConcurrentDictionary<Type, Type> _types = new ConcurrentDictionary<Type, Type>();
private AssemblyBuilder _assemblyBuilder = null;
private volatile ModuleBuilder _moduleBuilder = null;
private object _lock = new object();
private void EnsureInitialized()
{
if (_moduleBuilder == null) {
lock (_lock) {
if (_moduleBuilder == null) {
_assemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(new AssemblyName(_assemblyNameBase), AssemblyBuilderAccess.RunAndSave);
_moduleBuilder = _assemblyBuilder.DefineDynamicModule(_assemblyBuilder.GetName().Name, _assemblyNameBase + ".dll");
}
}
}
}
public void SaveAssembly() { _assemblyBuilder.Save(_assemblyNameBase + ".dll"); }
public TSettings CreateInstance<TSettings>() { return (TSettings)Activator.CreateInstance(_types.GetOrAdd(typeof(TSettings), CreateImplementation)); }
public void CreateImplementations(IEnumerable<Type> types) { foreach (var t in types) _types.GetOrAdd(t, InternalCreateImplementation); }
public Type CreateImplementation(Type interfaceType) { return _types.GetOrAdd(interfaceType, InternalCreateImplementation); }
private Type InternalCreateImplementation(Type interfaceType)
{
EnsureInitialized();
var baseType = typeof (ImplBase<>).MakeGenericType(interfaceType);
var typeBuilder = _moduleBuilder.DefineType(
(interfaceType.IsInterface && interfaceType.Name.StartsWith("I")
? interfaceType.Name.Substring(1)
: interfaceType.Name) + "Impl",
TypeAttributes.Public | TypeAttributes.Class |
TypeAttributes.AutoClass | TypeAttributes.AnsiClass |
TypeAttributes.BeforeFieldInit | TypeAttributes.AutoLayout,
baseType,
new [] {interfaceType});
foreach (var p in GetPublicProperties(interfaceType).Where(pi => pi.DeclaringType != typeof(IBase))) {
var iGet = p.GetGetMethod();
if (iGet != null) {
var getBuilder =
typeBuilder.DefineMethod(iGet.Name,
MethodAttributes.Public | MethodAttributes.Virtual | MethodAttributes.SpecialName | MethodAttributes.HideBySig,
p.PropertyType, Type.EmptyTypes);
//EmitILForGetMethod(getBuilder, interfaceType, baseType, p, iGet);
CreateExpressionForGetMethod(getBuilder, interfaceType, baseType, p, iGet);
typeBuilder.DefineMethodOverride(getBuilder, iGet);
}
}
var implementationType = typeBuilder.CreateType();
return implementationType;
}
public void CreateExpressionForGetMethod(MethodBuilder getBuilder, Type interfaceType, Type baseType, PropertyInfo property, MethodInfo getMethod)
{
var settingsParam = Expression.Parameter(interfaceType, "s");
var propGetterExpr = Expression.Property(settingsParam, property);
var propGetterExprFuncType = typeof(Func<,>).MakeGenericType(interfaceType, property.PropertyType);
var propGetterLambda = Expression.Lambda(propGetterExprFuncType, propGetterExpr, settingsParam);
var baseGetMethodInfo =
baseType.GetMethods(BindingFlags.Instance | BindingFlags.NonPublic)
.Where(m => {
var parameters = m.GetParameters();
return m.Name == "Get" &&
parameters != null && parameters.Count() == 1 && parameters[0].ParameterType != typeof(string);
})
.First().MakeGenericMethod(property.PropertyType);
var getExprType = typeof(Expression<>).MakeGenericType(propGetterExprFuncType);
var getExprParam = Expression.Parameter(getExprType, "expression");
var getCallExpr = Expression.Call(Expression.Parameter(baseType, "inst"), baseGetMethodInfo, propGetterLambda);
var getFuncType = typeof(Func<,>).MakeGenericType(getExprType, property.PropertyType);
var propLambda = Expression.Lambda(getFuncType, getCallExpr, getExprParam);
propLambda.CompileToMethod(getBuilder);
}
public void EmitILForGetMethod(MethodBuilder getBuilder, Type interfaceType, Type baseType, PropertyInfo property, MethodInfo getMethod)
{
var getGen = getBuilder.GetILGenerator();
var retVal = getGen.DeclareLocal(property.PropertyType);
var expParam = getGen.DeclareLocal(typeof(ParameterExpression));
var expParams = getGen.DeclareLocal(typeof(ParameterExpression[]));
getGen.Emit(OpCodes.Ldarg_0);
getGen.Emit(OpCodes.Ldtoken, interfaceType);
getGen.Emit(OpCodes.Call, typeof(Type).GetMethod("GetTypeFromHandle"));
getGen.Emit(OpCodes.Ldstr, "s");
getGen.Emit(OpCodes.Call, typeof(Expression).GetMethod("Parameter", new [] {typeof(Type), typeof(string)}));
getGen.Emit(OpCodes.Stloc, expParam);
getGen.Emit(OpCodes.Ldloc, expParam);
getGen.Emit(OpCodes.Ldtoken, getMethod);
getGen.Emit(OpCodes.Call, typeof(MethodBase).GetMethod("GetMethodFromHandle", new [] {typeof(RuntimeMethodHandle)}, null));
getGen.Emit(OpCodes.Castclass, typeof(MethodInfo));
getGen.Emit(OpCodes.Call, typeof(Expression).GetMethod("Property", new[] {typeof(Expression), typeof(MethodInfo)}));
getGen.Emit(OpCodes.Ldc_I4_1);
getGen.Emit(OpCodes.Newarr, typeof(ParameterExpression));
getGen.Emit(OpCodes.Stloc, expParams);
getGen.Emit(OpCodes.Ldloc, expParams);
getGen.Emit(OpCodes.Ldc_I4_0);
getGen.Emit(OpCodes.Ldloc, expParam);
getGen.Emit(OpCodes.Stelem_Ref);
getGen.Emit(OpCodes.Ldloc, expParams);
var lambdaMethodInfo =
typeof(Expression).GetMethods(BindingFlags.Public | BindingFlags.Static)
.Where(x => {
var parameters = x.GetParameters();
return x.Name == "Lambda" &&
x.IsGenericMethodDefinition &&
parameters.Count() == 2 &&
parameters[0].ParameterType == typeof(Expression) &&
parameters[1].ParameterType == typeof(ParameterExpression[]);
}).FirstOrDefault();
var lambdaFuncType = typeof(Func<,>);
lambdaFuncType = lambdaFuncType.MakeGenericType(interfaceType, property.PropertyType);
lambdaMethodInfo = lambdaMethodInfo.MakeGenericMethod(lambdaFuncType);
getGen.Emit(OpCodes.Call, lambdaMethodInfo);
var baseGetMethodInfo =
baseType.GetMethods(BindingFlags.Instance | BindingFlags.NonPublic)
.Where(m => {
var parameters = m.GetParameters();
return m.Name == "Get" &&
parameters != null && parameters.Count() == 1 && parameters[0].ParameterType != typeof(string);
}).FirstOrDefault();
baseGetMethodInfo = baseGetMethodInfo.MakeGenericMethod(property.PropertyType);
getGen.Emit(OpCodes.Callvirt, baseGetMethodInfo);
getGen.Emit(OpCodes.Stloc_0);
var endOfMethod = getGen.DefineLabel();
getGen.Emit(OpCodes.Br_S, endOfMethod);
getGen.MarkLabel(endOfMethod);
getGen.Emit(OpCodes.Ldloc_0);
getGen.Emit(OpCodes.Ret);
}
// from http://stackoverflow.com/a/2444090/224087
public static PropertyInfo[] GetPublicProperties(Type type)
{
if (!type.IsInterface)
return type.GetProperties(BindingFlags.FlattenHierarchy | BindingFlags.Public | BindingFlags.Instance);
var propertyInfos = new List<PropertyInfo>();
var considered = new List<Type>();
var queue = new Queue<Type>();
considered.Add(type);
queue.Enqueue(type);
while (queue.Count > 0) {
var subType = queue.Dequeue();
foreach (var subInterface in subType.GetInterfaces()) {
if (considered.Contains(subInterface))
continue;
considered.Add(subInterface);
queue.Enqueue(subInterface);
}
var typeProperties = subType.GetProperties(BindingFlags.FlattenHierarchy | BindingFlags.Public | BindingFlags.Instance);
var newPropertyInfos = typeProperties.Where(x => !propertyInfos.Contains(x));
propertyInfos.InsertRange(0, newPropertyInfos);
}
return propertyInfos.ToArray();
}
}
}

What I don't really understand is building the Call expression, if I'm setting it up correctly to do the equivalent of this.Get() or base.Get().
If you are calling a virtual method, then this.Get(), which accesses the most-derived override (which could even be defined in a descendant of the current class), uses the callvirt instruction. And it doesn't matter what type you reflect against to get the MethodInfo, because they all share the same virtual table slot.
To emit base.Get(), you must
use the call instruction
reflect against the base class type
Because callvirt does some extra things besides v-table lookup, including a null pointer check, the C# compiler uses it for all virtual and non-virtual calls, except those involving the base keyword.
In particular, anonymous delegates and lambdas can't make use of the base keyword, since only descendant types can make non-virtual calls to virtual methods (at least in verifiable code), and the lambda is actually hosted by a closure type.
So unfortunately for your use case, there's no way to express a base call using lambda notation or expression trees. Expression.CompileToMethod only generates callvirt. Well, that isn't exactly correct. It generates call for calls to static methods and instance methods of value types. But instance methods of reference types use only callvirt. You can see this in System.Linq.Expressions.Compiler.LambdaCompiler.UseVirtual
Thanks #hvd for confirming this based on comments found in the Microsoft Reference Source for UseVirtual

Convert Dictionary<string, object> To Anonymous Object?

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?

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;

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;

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

If you have a class you want to covert the dictionary too, you can use the following to convert a dictionary to an object of that class:
Example class:
public class Properties1
{
public string Property { get; set; }
}
The solution:
JavaScriptSerializer serializer = new JavaScriptSerializer();
Dictionary<string, object> dict = new Dictionary<string, object> { { "Property", "foo" } };
Properties1 properties = serializer.ConvertToType<Properties1>(dict);
string value = properties.Property;
You could also use a method like this to build the object from the dictionary, obviously this also requires you to have a class.
private static T DictionaryToObject<T>(IDictionary<string, object> dict) where T : new()
{
T t = new T();
PropertyInfo[] properties = t.GetType().GetProperties();
foreach (PropertyInfo property in properties)
{
if (!dict.Any(x => x.Key.Equals(property.Name,
StringComparison.InvariantCultureIgnoreCase)))
continue;
KeyValuePair<string, object> item = dict.First(x => x.Key.Equals(property.Name,
StringComparison.InvariantCultureIgnoreCase));
Type tPropertyType = t.GetType().GetProperty(property.Name).PropertyType;
Type newT = Nullable.GetUnderlyingType(tPropertyType) ?? tPropertyType;
object newA = Convert.ChangeType(item.Value, newT);
t.GetType().GetProperty(property.Name).SetValue(t, newA, null);
}
return t;
}
However if you do not have the class you can create a dynamic object from a dictionary like this:
private static dynamic DictionaryToObject(Dictionary<string, object> dict)
{
IDictionary<string, object> eo = (IDictionary<string, object>)new ExpandoObject();
foreach (KeyValuePair<string, object> kvp in dict)
{
eo.Add(kvp);
}
return eo;
}
You can use it like this:
Dictionary<string, object> dict = new Dictionary<string, object> {{ "Property", "foo" }};
dynamic properties = DictionaryToObject(dict);
string value = properties.Property;

Slightly more modular version of svick's answer, using a couple extension methods:
public static class Extensions
{
public static void AddRange<T>(this ICollection<T> collection, IEnumerable<T> items)
{
foreach (var item in items)
{
collection.Add(item);
}
}
public static dynamic ToDynamicObject(this IDictionary<string, object> source)
{
ICollection<KeyValuePair<string, object>> someObject = new ExpandoObject();
someObject.AddRange(source);
return someObject;
}
}

The code below handles sub-dictionaries and converts them to nested dynamic objects as well:
[return: NotNullIfNotNull(nameof(dictionary))]
static dynamic? ToDynamic(IReadOnlyDictionary<string, object?>? dictionary) =>
dictionary?.Aggregate(
(IDictionary<string, object?>)new ExpandoObject(),
(obj, i) =>
{
if (i.Value is IReadOnlyDictionary<string, object?> nestedDictionary)
obj.Add(new(i.Key, ToDynamic(nestedDictionary)));
else
obj.Add(i);
return obj;
});
This approach allows you to access the contents of nested dictionaries just by accessing the dynamic object itself:
var record = ToDynamic(...);
string cityName = record.city.name;

Anonymous objects are one that generated for you by compiler. You cannot generate dynamically create one. On the other hand you can emit such object, but I really do not think this is good idea.
May be you can try dynamic objects? The result will be an object with all properties you need.

The credit here goes to the accepted answer. Adding this because I wanted to turn a List< Dictionary< string,object >> into a List< dynamic>. The purpose is for pulling records from a database table. Here is what I did.
public static List<dynamic> ListDictionaryToListDynamic(List<Dictionary<string,object>> dbRecords)
{
var eRecords = new List<dynamic>();
foreach (var record in dbRecords)
{
var eRecord = new ExpandoObject() as IDictionary<string, object>;
foreach (var kvp in record)
{
eRecord.Add(kvp);
}
eRecords.Add(eRecord);
}
return eRecords;
}