Find a private field with Reflection?

Question

Given this class

class Foo
{
    // Want to find _bar with reflection
    [SomeAttribute]
    private string _bar;

    public string BigBar
    {
        ge         


        

Answer 1

Here is some extension methods for simple get and set private fields and properties (properties with setter):

usage example:

    public class Foo
    {
        private int Bar = 5;
    }

    var targetObject = new Foo();
    var barValue = targetObject.GetMemberValue("Bar");//Result is 5
    targetObject.SetMemberValue("Bar", 10);//Sets Bar to 10

Code:

    /// 

    /// Extensions methos for using reflection to get / set member values
    /// 
    public static class ReflectionExtensions
    {
        /// 

        /// Gets the public or private member using reflection.
        /// 
        /// The source target.
        /// Name of the field or property.
        /// the value of member
        public static object GetMemberValue(this object obj, string memberName)
        {
            var memInf = GetMemberInfo(obj, memberName);

            if (memInf == null)
                throw new System.Exception("memberName");

            if (memInf is System.Reflection.PropertyInfo)
                return memInf.As().GetValue(obj, null);

            if (memInf is System.Reflection.FieldInfo)
                return memInf.As().GetValue(obj);

            throw new System.Exception();
        }

        /// 

        /// Gets the public or private member using reflection.
        /// 
        /// The target object.
        /// Name of the field or property.
        /// Old Value
        public static object SetMemberValue(this object obj, string memberName, object newValue)
        {
            var memInf = GetMemberInfo(obj, memberName);


            if (memInf == null)
                throw new System.Exception("memberName");

            var oldValue = obj.GetMemberValue(memberName);

            if (memInf is System.Reflection.PropertyInfo)
                memInf.As().SetValue(obj, newValue, null);
            else if (memInf is System.Reflection.FieldInfo)
                memInf.As().SetValue(obj, newValue);
            else
                throw new System.Exception();

            return oldValue;
        }

        /// 

        /// Gets the member info
        /// 
        /// source object
        /// name of member
        /// instanse of MemberInfo corresponsing to member
        private static System.Reflection.MemberInfo GetMemberInfo(object obj, string memberName)
        {
            var prps = new System.Collections.Generic.List();

            prps.Add(obj.GetType().GetProperty(memberName,
                                               System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance |
                                               System.Reflection.BindingFlags.FlattenHierarchy));
            prps = System.Linq.Enumerable.ToList(System.Linq.Enumerable.Where( prps,i => !ReferenceEquals(i, null)));
            if (prps.Count != 0)
                return prps[0];

            var flds = new System.Collections.Generic.List();

            flds.Add(obj.GetType().GetField(memberName,
                                            System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance |
                                            System.Reflection.BindingFlags.FlattenHierarchy));

            //to add more types of properties

            flds = System.Linq.Enumerable.ToList(System.Linq.Enumerable.Where(flds, i => !ReferenceEquals(i, null)));

            if (flds.Count != 0)
                return flds[0];

            return null;
        }

        [System.Diagnostics.DebuggerHidden]
        private static T As(this object obj)
        {
            return (T)obj;
        }
    }