Question: I have a 25MB json file, that I "require" why my app starts up. Initial it seems that the node.js process takes up almost 200MB of memory.

But if I leave it running and come back to it, Activity monitor reports that it is using only 9MB which makes no sense at all! At the very least, it should be a few MB more, since even a simple node.js app that does almost nothing (acting like a server), uses 9MB.

The app seems to work fine - it is a server, that provides search suggestions form a word list of 220,000 words.

Is Activity Monitor wrong ?
Why is it using only 9MB, but initially used ~200MB when the application started up ?

Answer: 
Starting from .Net 4 it is possible in WPF. You can then host the WPF `datepicker` inside a Winforms app. An example (from MSDN) to disable Saturdays and Sundays:

```
DatePicker datePickerWithBlackoutDates = new DatePicker();

datePickerWithBlackoutDates.DisplayDateStart = new DateTime(2009, 8, 1);
datePickerWithBlackoutDates.DisplayDateEnd = new DateTime(2009, 8, 31);
datePickerWithBlackoutDates.SelectedDate = new DateTime(2009, 8, 10);

datePickerWithBlackoutDates.BlackoutDates.Add(
    new CalendarDateRange(new DateTime(2009, 8, 1), new DateTime(2009, 8, 2)));
datePickerWithBlackoutDates.BlackoutDates.Add(
    new CalendarDateRange(new DateTime(2009, 8, 8), new DateTime(2009, 8, 9)));
datePickerWithBlackoutDates.BlackoutDates.Add(
    new CalendarDateRange(new DateTime(2009, 8, 15), new DateTime(2009, 8, 16)));
datePickerWithBlackoutDates.BlackoutDates.Add(
    new CalendarDateRange(new DateTime(2009, 8, 22), new DateTime(2009, 8, 23)));
datePickerWithBlackoutDates.BlackoutDates.Add(
    new CalendarDateRange(new DateTime(2009, 8, 29), new DateTime(2009, 8, 30)));

datePickerWithBlackoutDates.DateValidationError +=
new EventHandler<DatePickerDateValidationErrorEventArgs>(DatePicker_DateValidationError);

```

More details on MSDN: <http://msdn.microsoft.com/en-us/library/k7z0zy8k%28v=vs.110%29.aspx>

I haven't seen anything similar that would be specifically for Winforms though. As a workaround you can port this WPF component into Winforms app.

Here's MSDN resource on **interopeartion of WPF and Winforms**:

<https://msdn.microsoft.com/en-us/library/ms751797(v=vs.100).aspx>
You can specify a max date, but you cannot selectively disable arbitrary dates in the valid range.

Please see [How do I disable some dates on a DateTimePicker control?](https://stackoverflow.com/questions/2361691/how-do-i-disable-some-dates-on-a-datetimepicker-control)