I have an Structure in a Class where i have a property named 'Name'. and other properties values inside the structure depends of the set of this value, is there any way to make them publics only when this first property is Set ?.
When i create an instance of the class , and access to this structure all the properties are available.
I would hook up these properties with an ICommand implementation.
For each property that depends on Name, they can use CanExecute to determine if Name is set. If so, CanExecute will return true, and the Command will be executed for the property (which can hook up to a method to do anything you want...get a value, set a value, etc.)
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I'm trying to understand something about type properties in swift.
The Swift Programming Language says
For classes, you can define computed type properties only
So a computed property does not store a value itself, but it is calculated. That I understand. But I don't get how such a thing can apply to type properties. Such properties belong to the class itself and not to an instance of it.
So if you use a getter for such a computed type property, what could you possibly use to calculate it? It can't be any other type properties, as they too can only be computed properties. You would get a sort of loop of computed properties because there aren't any stored type properties.
In the same way, I also don't get what a setter would do. If you call the setter of a computed type property, what can it set? There are no stored type properties to be set.
Bear in mind that stored class properties are only unsupported at the moment. The compiler error you get when you try to use them—"Class variables not yet supported"— suggests that they're on their way. Computed class properties don't necessarily have to make sense on their own.
However, computed properties don't always have to be based on the values of stored data. As it stands, you could use them for "static" read-only values associated with the class, say:
class var ThisIsAClassConstant: String { return "Woo" }
And people have already come up with ways to store associated values, for example, in the first two singleton patterns in this answer, the class property stores its state in either a global (but private) variable, or in a static variable inside a nested structure.
These are obviously a bit "workaroundy", but they're a way of achieving class-like storage while it's not officially implemented.
In the auto-generated resource designer file, there are properties for each resource. The property calls "GetString" which returns the string value. I would like to override this getstring function so I can do logic to see if I need to retrieve this value or a different value. I can't figure out how to do this because the designer file is auto-generated.
Public ReadOnly Property General() As String
Get
Return ResourceManager.GetString("General", resourceCulture)
End Get
End Property
For example, in my version of the GetString function, I would check the key passed in ("General") and see if there is a custom value for this key in a database. If the custom value exists, I would use that value. If the custom value does not exist, I would call the base GetString function to get the Resource value. I'd like to use the built in Resource class for this because then in my code I can just use "#Resources.General" and take advantage of the auto-complete functionality that already exists.
Refer to ASP.NET Resourcemanager to read local .resx. It's in C# but you can just convert it over. It isn't 100% of what you are looking for but shows a way of overriding in which you may be able to adjust to work with your needs.
I remember coming across some way to declare multiple Set handlers in a property but now I can't figure out how it's done. It's useful in that one can assign different data types and the Set handler does the conversion, but I get the error
'Set' is already declared
thoughts anyone?
It's not possible
It would be nice to be able to write both
sQuantity = "1234"
and
sQuantity = 1234
with two setter functions, but trying to write even one setter function with the wrong parameter type seems doomed to failure:-
error BC31064: 'Set' parameter must have the same type as the containing property.
If Visual Basic doesn't allow conversion between setter parameter type and property type then there is no way it would be possible to have two setter functions. If setter functions are forced to have the same type as the property, then it could not know which to run if there were more than one!
So I'd argue 'not only does it not seem possible, but it is actually not possible!'
There is a workaround
What you can do however, is have two properties of different types changing the same underlying variable, so that you can write
sQuantityFromString = "1234"
and
sQuantityFromInt = 1234
using
Public Shared WriteOnly Property sQuantityFromInt () As Integer
with a setter function that takes an integer as a parameter and with both properties setter functions modifying the same underlying string member variable.
Private Shared m_sQuantity As String = Nothing
As far as I know, you cannot have multiple Set statements for a class property. A property cannot be overridden.
You can use a setter functions (this is mostly a paradigm in Java) and overload that if you need to. Then I would also suggest making the property readonly.
One other option is to have the property be defined as an Object and in the set check the TypeOf of the value being used to set the property and do whatever business logic you want. The only problem with this approach is that then your property doesn't have type checking.
I want to make a custom getter that should return two fields of the model instead of one. I have the attribute name like first_name. And the getter I am making is
public function getFirstName(){
return 1;
}
And then I try to get it called in a CDetailView like this
'client.first_name:raw:Client',
But it returns the standard attribute of the model. How to do it right?
Yii's order of operations to retrieve an attribute is as follows:
AR attribute
public variable
custom getter
I'm not sure whether AR attributes or public variables are pulled first, but I do know that if either of them exist, your custom getter won't be called.
If you already have a first_name attribute (from AR), then you'll need to use a different name for your getter and use that.
Is setX() method name appropriate for only for setting class property X?
For instance, I have a class where the output is a string of an html table. Before you can you can call getTable, you have to call setTable(), which just looks at a other properties and decides how to construct the table. It doesn't actually directly set any class property -- only causes the property to be set. When it's called, the class will construct strHtmlTable, but you can't specify it.
So, calling it setTable breaks the convention of get and set being interfaces for class properties.
Is there another naming convention for this kind of method?
Edit: in this particular class, there are at least two ( and in total 8 optional ) other methods that must be called before the class knows everything it needs to to construct the table. I chose to have the data set as separate methods rather than clutter up the __construct() with 8 optional parameters which I'll never remember the order of.
I would recommend something like generateTable() instead of setTable(). This provides a situation where the name of the method clearly denotes what it does.
I would probably still use a setTable() method to actually set the property, though. Ideally, you could open the possibility of setting a previously defined table for further flexibility.
Yes, setX() is primarily used for setting a field X, though setX() may have some additional code that needs to run in addition to a direct assignment to a field. Using it for something else may be misleading to other developers.
I would definitely recommend against having a public setTable() and would say that setTable() could be omitted or just an unused private method depending upon your requirements.
It sounds like the activity to generate the table is more of a view of other properties on the object, so you might consider moving that to a private method on the object like generateHtmlTable(). This could be done during construction (and upon updates to the object) so that any subsequent calls to getTable() will return the the appropriate HTML.