Est-il possible de définir la propriété privée par réflexion?

Puis-je définir une propriété privée par réflexion?

public abstract class Entity
{
    private int _id;
    private DateTime? _createdOn;
    public virtual T Id
    {
        get { return _id; }
        private set { ChangePropertyAndNotify(ref _id, value, x => Id); }
    }
    public virtual DateTime? CreatedOn
    {
        get { return _createdOn; }
        private set { ChangePropertyAndNotify(ref _createdOn, value, x => CreatedOn); }
    }
}

J'ai essayé ce qui suit et cela ne fonctionne pas, où treprésente un type de Entity:

var t = typeof(Entity);
var mi = t.GetMethod("set_CreatedOn", BindingFlags.Instance | BindingFlags.NonPublic);

Je suppose que je peux le faire mais je ne peux pas y arriver.

t.GetProperty("CreatedOn")
    .SetValue(obj, new DateTime(2009, 10, 14), null);

EDIT: Puisque la propriété elle-même est publique, vous n'avez apparemment pas besoin de l'utiliser BindingFlags.NonPublicpour la trouver. Appeler SetValuemalgré le fait que le setter ait moins d'accessibilité fait toujours ce que vous attendez.

Oui, ça l'est:

/// <summary>
/// Returns a _private_ Property Value from a given Object. Uses Reflection.
/// Throws a ArgumentOutOfRangeException if the Property is not found.
/// </summary>
/// <typeparam name="T">Type of the Property</typeparam>
/// <param name="obj">Object from where the Property Value is returned</param>
/// <param name="propName">Propertyname as string.</param>
/// <returns>PropertyValue</returns>
public static T GetPrivatePropertyValue<T>(this object obj, string propName)
{
    if (obj == null) throw new ArgumentNullException("obj");
    PropertyInfo pi = obj.GetType().GetProperty(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
    if (pi == null) throw new ArgumentOutOfRangeException("propName", string.Format("Property {0} was not found in Type {1}", propName, obj.GetType().FullName));
    return (T)pi.GetValue(obj, null);
}

/// <summary>
/// Returns a private Property Value from a given Object. Uses Reflection.
/// Throws a ArgumentOutOfRangeException if the Property is not found.
/// </summary>
/// <typeparam name="T">Type of the Property</typeparam>
/// <param name="obj">Object from where the Property Value is returned</param>
/// <param name="propName">Propertyname as string.</param>
/// <returns>PropertyValue</returns>
public static T GetPrivateFieldValue<T>(this object obj, string propName)
{
    if (obj == null) throw new ArgumentNullException("obj");
    Type t = obj.GetType();
    FieldInfo fi = null;
    while (fi == null && t != null)
    {
        fi = t.GetField(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
        t = t.BaseType;
    }
    if (fi == null) throw new ArgumentOutOfRangeException("propName", string.Format("Field {0} was not found in Type {1}", propName, obj.GetType().FullName));
    return (T)fi.GetValue(obj);
}

/// <summary>
/// Sets a _private_ Property Value from a given Object. Uses Reflection.
/// Throws a ArgumentOutOfRangeException if the Property is not found.
/// </summary>
/// <typeparam name="T">Type of the Property</typeparam>
/// <param name="obj">Object from where the Property Value is set</param>
/// <param name="propName">Propertyname as string.</param>
/// <param name="val">Value to set.</param>
/// <returns>PropertyValue</returns>
public static void SetPrivatePropertyValue<T>(this object obj, string propName, T val)
{
    Type t = obj.GetType();
    if (t.GetProperty(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance) == null)
        throw new ArgumentOutOfRangeException("propName", string.Format("Property {0} was not found in Type {1}", propName, obj.GetType().FullName));
    t.InvokeMember(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.SetProperty | BindingFlags.Instance, null, obj, new object[] { val });
}

/// <summary>
/// Set a private Property Value on a given Object. Uses Reflection.
/// </summary>
/// <typeparam name="T">Type of the Property</typeparam>
/// <param name="obj">Object from where the Property Value is returned</param>
/// <param name="propName">Propertyname as string.</param>
/// <param name="val">the value to set</param>
/// <exception cref="ArgumentOutOfRangeException">if the Property is not found</exception>
public static void SetPrivateFieldValue<T>(this object obj, string propName, T val)
{
    if (obj == null) throw new ArgumentNullException("obj");
    Type t = obj.GetType();
    FieldInfo fi = null;
    while (fi == null && t != null)
    {
        fi = t.GetField(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
        t = t.BaseType;
    }
    if (fi == null) throw new ArgumentOutOfRangeException("propName", string.Format("Field {0} was not found in Type {1}", propName, obj.GetType().FullName));
    fi.SetValue(obj, val);
}

Vous pouvez accéder au setter privé à partir du type dérivé via le code

public static void SetProperty(object instance, string propertyName, object newValue)
{
    Type type = instance.GetType();

    PropertyInfo prop = type.BaseType.GetProperty(propertyName);

    prop.SetValue(instance, newValue, null);
}

Aucun de ces éléments n'a fonctionné pour moi, et le nom de ma propriété était unique, alors j'ai simplement utilisé ceci:

public static void SetPrivatePropertyValue<T>(T obj, string propertyName, object newValue)
{
    // add a check here that the object obj and propertyName string are not null
    foreach (FieldInfo fi in obj.GetType().GetFields(BindingFlags.Instance | BindingFlags.NonPublic))
    {
        if (fi.Name.ToLower().Contains(propertyName.ToLower()))
        {
            fi.SetValue(obj, newValue);
            break;
        }
    }
}

    //mock class
    public class Person{
        public string Name{get; internal set;}
    }

    // works for all types, update private field through reflection
    public static T ReviveType<T>(T t, string propertyName, object newValue){
        // add a check here that the object t and propertyName string are not null
        PropertyInfo pi = t.GetType().GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance);
         pi.SetValue(t, newValue, null); 
        return t;
    }

    // check the required function
    void Main()
    {
        var p = new Person(){Name="John"};
        Console.WriteLine("Name: {0}",p.Name);

        //box the person to object, just to see that the method never care about what type you pass it
        object o = p;
        var updatedPerson = ReviveType<Object>(o, "Name", "Webber") as Person;

         //check if it updated person instance
        Console.WriteLine("Name: {0}",updatedPerson.Name);
    }



// Console Result: -------------------
Name: John
Name: Webber