public class TestClass
{
private int FValue;
public TestClass(int val) : base()
{
 FValue = val;
}
public int Value
{
 get { return FValue; }
}
}

static void Main(string[] args)
{
TestClass tc = new TestClass(123);

Type t = tc.GetType();
FieldInfo[] fields = t.GetFields(BindingFlags.NonPublic | BindingFlags.Instance);
foreach (FieldInfo field in fields) Console.WriteLine(field.Name);
}

static void Main(string[] args)
{
TestClass tc = new TestClass(123);
Console.WriteLine(tc.Value);
Type t = tc.GetType();
t.InvokeMember("FValue", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.SetField , null, tc, new object[]{456});
Console.WriteLine(tc.Value);  
}

interface

uses
 System.Reflection;

type

 PropertyAdapter = class
 protected
   procedure CloneProperties(SourceAssemblyName, SourceTypeName: System.string); virtual;
   constructor Create(SourceAssemblyName, SourceTypeName: System.string); virtual;
 end;

 NativeMethodsAdapter = class(PropertyAdapter)
 private
 protected
 public
   fWM_CREATE: Integer;
   fWM_MOVE, fWM_MOVING: Integer;
   constructor Create; reintroduce; virtual;
   property WM_MOVE: Integer read fWM_MOVE;
   property WM_MOVING: Integer read fWM_MOVING;
   property WM_CREATE: Integer read fWM_CREATE;
 end;

function GetCurrentAppDomainAssembly(AssemblyName: System.string): Assembly;

function GetCurrentAppDomainAssemblyObject(SourceAssemblyName, SourceTypeName: System.string): System.object;

implementation

function GetCurrentAppDomainAssembly(AssemblyName: System.string): Assembly;
var
 Assemblies        : array of Assembly;
 I                 : Integer;
begin
 Result := Assembly.LoadWithPartialName(AssemblyName);
 if Assigned(Result) then
   Exit
 else
 begin
   Assemblies := AppDomain.get_CurrentDomain.GetAssemblies;
   for I := Low(Assemblies) to High(Assemblies) do
   begin
     Result := Assemblies[I];
     if Result.GetName.Name.Equals(AssemblyName) then
       Exit
     else
       Result := nil;
   end;
 end;
end;

function GetCurrentAppDomainAssemblyObject(SourceAssemblyName, SourceTypeName: System.string): System.object;
var
 SourceAssembly    : Assembly;
 SourceType        : System.Type;
begin
 Result := nil;
 SourceAssembly := GetCurrentAppDomainAssembly(SourceAssemblyName);
 if Assigned(SourceAssembly) then
   with SourceAssembly do
   begin
     SourceType := GetType(System.string.Format('{0}.{1}', [SourceAssemblyName, SourceTypeName]));
     if Assigned(SourceType) then
       Result := Activator.CreateInstance(SourceType);
   end;
end;

{ PropertyAdapter }

procedure PropertyAdapter.CloneProperties(SourceAssemblyName, SourceTypeName: System.string);
var
 MyProps           : array of PropertyInfo;
 MyProp            : PropertyInfo;
 MyField           : FieldInfo;
 SourceObject      : System.object;
 SourceField       : FieldInfo;
begin
 SourceObject := GetCurrentAppDomainAssemblyObject(SourceAssemblyName, SourceTypeName);
 if Assigned(SourceObject) then
 begin
   MyProps := GetType.GetProperties;
   if Assigned(MyProps) then
     for MyProp in MyProps do
     begin
       SourceField := SourceObject.GetType.GetField(MyProp.Name);
       if Assigned(SourceField) then
       begin
         MyField := GetType.GetField('f' + MyProp.Name);
         MyField.SetValue(Self, SourceField.GetValue(SourceObject));
       end;
     end;
 end;
end;

constructor PropertyAdapter.Create(SourceAssemblyName, SourceTypeName: System.string);
begin
 inherited Create;
 CloneProperties(SourceAssemblyName, SourceTypeName);
end;

{ NativeMethodsAdapter }

constructor NativeMethodsAdapter.Create;
begin
 inherited Create('System.Windows.Forms', 'NativeMethods');
end;

end.

procedure TObject.CleanupInstance;
{$IFDEF PUREPASCAL}
var
 ClassPtr: TClass;
 InitTable: Pointer;
begin
 ClassPtr := ClassType;
 InitTable := PPointer(Integer(ClassPtr) + vmtInitTable)^;
 while (ClassPtr <> nil) and (InitTable <> nil) do
 begin
   _FinalizeRecord(Self, InitTable); // вот оно. Ссылка на TypeInfo полей
   ClassPtr := ClassPtr.ClassParent;
   if ClassPtr <> nil then
     InitTable := PPointer(Integer(ClassPtr) + vmtInitTable)^;
 end;
end;