ANSWER is: No, this is not a bug. The difference is in the ReflectedType.
So the real question here is: Is there a way of comparing two PropertyInfo objects, for the same property, but reflected from different types, so that it returns true?
Original question
This code produces two PropertyInfo objects for the very same property, by using two different ways. It comes that, these property infos compare differently somehow. I have lost some time trying to figure out this out.
What am I doing wrong?
using System;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
namespace TestReflectionError
{
class Program
{
static void Main(string[] args)
{
Console.BufferWidth = 200;
Console.WindowWidth = 200;
Expression<Func<object>> expr = () => ((ClassA)null).ValueA;
PropertyInfo pi1 = (((expr as LambdaExpression)
.Body as UnaryExpression)
.Operand as MemberExpression)
.Member as PropertyInfo;
PropertyInfo pi2 = typeof(ClassB).GetProperties()
.Where(x => x.Name == "ValueA").Single();
Console.WriteLine("{0}, {1}, {2}, {3}, {4}", pi1, pi1.DeclaringType, pi1.MemberType, pi1.MetadataToken, pi1.Module);
Console.WriteLine("{0}, {1}, {2}, {3}, {4}", pi2, pi2.DeclaringType, pi2.MemberType, pi2.MetadataToken, pi2.Module);
// these two comparisons FAIL
Console.WriteLine("pi1 == pi2: {0}", pi1 == pi2);
Console.WriteLine("pi1.Equals(pi2): {0}", pi1.Equals(pi2));
// this comparison passes
Console.WriteLine("pi1.DeclaringType == pi2.DeclaringType: {0}", pi1.DeclaringType == pi2.DeclaringType);
Console.ReadKey();
}
}
class ClassA
{
public int ValueA { get; set; }
}
class ClassB : ClassA
{
}
}
The output here is:
Int32 ValueA, TestReflectionError.ClassA, Property, 385875969, TestReflectionError.exe
Int32 ValueA, TestReflectionError.ClassA, Property, 385875969, TestReflectionError.exe
pi1 == pi2: False
pi1.Equals(pi2): False
pi1.DeclaringType == pi2.DeclaringType: True
Culprit: PropertyInfo.ReflectedType
I have found a difference between these two objects... it is in the ReflectedType. The documentation says this:
Gets the class object that was used to obtain this member.