public static  void DoitNow(object obj)
    {
        Queue<PropertyInfo> properties = new Queue<PropertyInfo>(obj.GetType().GetProperties());
        while (properties.Count != 0)
        {
            PropertyInfo property = properties.Dequeue();

            if (property.GetValue(obj) is string)
            {

                string stringField = property.GetValue(obj).ToString();

                String sanitizedField = sanitizeSensitiveString(stringField);
                property.SetValue(obj, sanitizedField);

            }
            else if (property.GetValue(obj) is IList)
            {
                IList y = (IList)property.GetValue(obj);


                if (y.Count != 0)
                {
                    if (y[0] is string)
                    {
                        for (int i = 0; i < y.Count; i++)
                            y[i] = sanitizeSensitiveString((string)y[i]);
                    }
                    else if (IsNested(y[0]))
                    {
                        for (int i = 0; i < y.Count; i++)
                        {
                            DoitNow(y[i]);
                        }
                    }
                }
            }
            else if (IsNested(property.GetValue(obj)))
            {

                var l = property.GetValue(obj);

                DoitNow(l);
            }

        }
    }
    public static string sanitizeSensitiveString(string sensitiveString)
    {
        return Regex.Replace(sensitiveString, @"\d{6}-?\d{4}[0-9]*", " XXXXXX-XXXX ");
    }
    public static bool IsNested(object value)
    {
        
        Type t = value.GetType();
        if (t.IsPrimitive || value is string)
        {
            return false;
        }
        FieldInfo[] fields = t.GetFields(BindingFlags.NonPublic |
                                         BindingFlags.Public |
                                         BindingFlags.Instance);
        if (fields.Any())
        {
            return true;
        }
        return false;
    }

Now, the method DoitNow is the core method here, it takes any object as a parameter, and uses projection to look through all the properties of it. If a field is a string field, we use the method sanitizeSensitiveString to sanitize the string. I a property is itself a object (I use the method isNested to determine this) I will call the method recursively on it. If a property is a List type, I look into the list and sanitize if it contains stirngs, and recurse if it contains complex objects.

I would like to get some tips on my Isnested method, am I using projection right? In general am I using projection In a way that makes sense to acces the fields and modify them?

Also, In order to be able to operate with many list types, I use the IList interface, however this has led me to using for-loops in a way that I find very un-elegant, can I replace some of my loops with some functional type function calls? I also use if (list.count != 0) to test if a list is empty, I just find this plain stupid.

public static void DoitNow(object obj)
{
    Queue<PropertyInfo> properties = new Queue<PropertyInfo>(obj.GetType().GetProperties());
    while (properties.Count != 0)
    {
        PropertyInfo property = properties.Dequeue();

        if (property.GetValue(obj) is string)
        {
            string stringField = property.GetValue(obj).ToString();

            String sanitizedField = sanitizeSensitiveString(stringField);
            property.SetValue(obj, sanitizedField);

        }
        else if (property.GetValue(obj) is IList)
        {
            IList y = (IList)property.GetValue(obj);

            if (y.Count != 0)
            {
                if (y[0] is string)
                {
                    for (int i = 0; i < y.Count; i++)
                        y[i] = sanitizeSensitiveString((string)y[i]);
                }
                else if (IsNested(y[0]))
                {
                    for (int i = 0; i < y.Count; i++)
                    {
                        DoitNow(y[i]);
                    }
                }
            }
        }
        else if (IsNested(property.GetValue(obj)))
        {
            var l = property.GetValue(obj);

            DoitNow(l);
        }
    }
}
    
public static string sanitizeSensitiveString(string sensitiveString)
{
    return Regex.Replace(sensitiveString, @"\d{6}-?\d{4}[0-9]*", " XXXXXX-XXXX ");
}

public static bool IsNested(object value)
{    
    Type t = value.GetType();
    if (t.IsPrimitive || value is string)
    {
        return false;
    }
    FieldInfo[] fields = t.GetFields(BindingFlags.NonPublic |
                                     BindingFlags.Public |
                                     BindingFlags.Instance);
    if (fields.Any())
    {
        return true;
    }
    return false;
}

Now, the method DoitNow is the core method here, it takes any object as a parameter, and uses projection to look through all the properties of it. If a field is a string field, we use the method sanitizeSensitiveString to sanitize the string. If a property is itself a object (I use the method isNested to determine this) I will call the method recursively on it. If a property is a List type, I look into the list and sanitize if it contains strings, and recurse if it contains complex objects.

I would like to get some tips on my IsNested method, am I using projection right? In general am I using projection In a way that makes sense to access the fields and modify them?

Also, In order to be able to operate with many list types, I use the IList interface, however this has led me to using for-loops in a way that I find very un-elegant, can I replace some of my loops with some functional type function calls? I also use if (list.count != 0) to test if a list is empty, I just find this plain stupid.