Using reflection on a abstract class with genericparameters to get a static value.

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We have a C#/C++ bridge (c# is running on a desktop and the c++ directly on hardware) that is auto generated from special c# files using abstract classes and interfaces to describe the communication bridge to our generator using reflexion.

In trying to remove some of the extra attributes used to do so and make them more c# like I hit a problem.

Is there a way of getting the value of the 'DefaultWindowSize' field using reflection?

C#

public abstract class Averager<InputType>
{
    //[Static, Value(10)] attributes removed
    public static int DefaultWindowSize = 10;

    public abstract AveragingMode AveragingMode { get; set; }
    public abstract uint NumberOfSamples { get; }
}

I have tried using:

C#

FieldInfo[] info = currentClass.GetFields(BindingFlags.Static);
object defueltValue = info[0].GetValue(null);

but this gives me a exception:
"Late bound operations cannot be performed on fields with types for which Type.ContainsGenericParameters is true."

Posted 26-Aug-11 4:21am

TheRaggers

Updated 28-Aug-11 5:01am

v2

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Manfred Rudolf Bihy 26-Aug-11 17:16pm

GetFields returns an array of FieldInfo instances. FieldInfo[] info ... and info[0].GetValue(null) should be correct.

TheRaggers 28-Aug-11 11:03am

Yes sorry that was a typo of me, I corrected it.

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Manfred Rudolf Bihy · Accepted Answer · 2011-08-26T11:13:00

I've just thrown this small sample together which demonstrates how to fetch the static fields from an abstract generic class:

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
namespace AbstractGeneric
{
    class Program
    {
        static void Main(string[] args)
        {
            Type myAbstractGenericType = typeof(AbstractGeneric<>);
            Type[] types = { typeof(int) };
            Type constructed = myAbstractGenericType.MakeGenericType(types);
            FieldInfo[] fieldInfos = constructed.GetFields(
                BindingFlags.NonPublic |
                BindingFlags.Public |
                BindingFlags.Static);
            foreach (FieldInfo fi in fieldInfos)
            {
                Console.WriteLine("Name: {0}  Value: {1}", fi.Name, fi.GetValue(null));
            }
            Console.ReadLine();
        }
    }
    public abstract class AbstractGeneric<T>
    {
        private static int anInt = 12345;
        private static String aString = "XXYYZZ";
        public abstract T WhatEver { get; set; }
    }
}

I hope this will help you. If you have any questions regarding this, feel free to add a comment below.

Best Regards,

—MRB