Is there a way to specify an additional field which is added to the auto-generated encoder of a case class? The field would be the type field of the sum type the case class is part of, so it generates valid json even in the case the encoder for a subclass is used.
Related
I'm using react-awesome-query-builder in my project. My requirement is having a field of type text and checking if this field is equals (achieved by using equal operator)/does not equal (achieved by using not_equal) a particular input string. SO far so good. I also want to check if the field contains some string? Looking for some help on how to check for java type string#contains functionality with this library.
My class Posts has a column that is a pointer to another class called Styles. Each post must be associated to a Style object as a rule of thumb.
My problem: I can't get only the posts that are associated to one or more styles.
My object selectedStyles, that is an array of PFObjects that already contains the style objects I would like to use to match the query. So populating the selectedStyles is not an issue, but how to use it to produce my query is.
What I am doing at the moment is:
override func queryForTable() -> PFQuery {
var query = PFQuery(className: "Posts")
query.whereKey("bellongsToStyle", containsAllObjectsInArray: [selectedStyles])
query.orderByDescending("createdAt")
return query
If I could translate the whereKey method in plain english I would say:
...contains - ANY OF THE - PFObjectsInArray [selectedStyles]
I am not so sure if that is possible... any ideas?!
I think I am too late for this but you can just add
[IncludeKey:"bellongsToStyle"]
when you are querying in your 'Posts' class
don't need to run any extra query for that
here's a small reference
http://blog.parse.com/announcements/queries-for-relational-data/
I have a SportsCentre class which contains an array of Employee objects.
Which is the right way to show that an attribute's data type is an array of objects?
I have found two different versions online:
the first one uses the ArrayList<> keyword:
SportsCentre
- listOfRegistered : ArrayList<Employee>
getRegisteredList() : ArrayList<Employee>
the second one uses square brackets []:
SportsCentre
- listOfRegistered : Employee[0..*]
getRegisteredList() : Employee[0..*]
Both are correct, but the second one, when multiplicity is set to more than one, is used more naturally, and it is not necessary to define the collection class as it is shown in the first picture of your example.
Simply said, multiplicity defines how many instances of a specific type can be stored by attribute. This set of instances can be ordered, or duplicates in it may be allowed. Parameters of multiplicity elements have an impact on the type of collection which should be used, Set, Vector, Array, etc.
But, if you need precise info about this issue, read UML Superstructure. Search for Property and Multiplicity Element. here is the UML website
I want to add movieclips which are instances of a certain class to an array (only add movie clips which are instances of BLAH). I can't find any property which refers to the movieclip's class. Can anyone help?
Use is operator:
if( mc is BLAH){
// here you are
}
From docs:
Evaluates whether an object is compatible with a specific data type,
class, or interface
I am attempting to set the Name property of a Page in the constructor:
public partial class PageListView : Page
{
public PageListView(string title)
{
InitializeComponent();
Name = title;
}
}
However, I often get the following error message.
'x' is not a valid value for property 'Name'.
Where x seems to be almost anything, drilling down into the exception details doesn't seem to provide any useful information (e.g. the InnerException is null.)
Does anyone know what is happening here?
The Name property generally follows the rules of C#/VB.NET identifiers (i.e. fields). Based on the documentation:
The string values used for Name have some restrictions, as imposed by
the underlying x:Name Directive defined by the XAML specification.
Most notably, a Name must start with a letter or the underscore character
(_), and must contain only letters, digits, or underscores.
Based on the parameter you are passing (i.e. title), it seems like you may violate that. But you'd have to give some specific examples to be sure.
Of course, moments after posting this I realised what's going on.
Because FrameworkElement.Name is used for creating object references, you have to ensure that the string contains only valid chars for an object instance variable name.
Use Title or another plain text property instead, unless you really want to set the x:Name property for referencing.