Access private members of a class using reflection

Accessing private members of a class is generally not recommended. However, there are cases where it is necessary. The following extension methods make it easier to do so:

public static T GetPrivateField<T>(this object obj, string name)
{
    BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
    Type type = obj.GetType();
    FieldInfo field = type.GetField(name, flags);
    return (T)field.GetValue(obj);
}

public static T GetPrivateProperty<T>(this object obj, string name)
{
    BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
    Type type = obj.GetType();
    PropertyInfo field = type.GetProperty(name, flags);
    return (T)field.GetValue(obj, null);
}

public static void SetPrivateField(this object obj, string name, object value)
{
    BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
    Type type = obj.GetType();
    FieldInfo field = type.GetField(name, flags);
    field.SetValue(obj, value);
}

public static void SetPrivateProperty(this object obj, string name, object value)
{
    BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
    Type type = obj.GetType();
    PropertyInfo field = type.GetProperty(name, flags);
    field.SetValue(obj, value, null);
}

public static T CallPrivateMethod<T>(this object obj, string name, params object[] param)
{
    BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
    Type type = obj.GetType();
    MethodInfo method = type.GetMethod(name, flags);
    return (T)method.Invoke(obj, param);
}

Note that recent versions of .NET have introduced a new way to do reflection when performance is a concern: Accessing private members without reflection in C#

Also, you can use a DynamicObject to simplify reflection: Easy reflection using a DynamicObject

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