I've a collection of a class' properties and would like to update each one's value by iterating over the collection through the index.
1) I create the collection of properties this way
private PropertyInfo[] GetPropertiesOfMyClass()
{
Type myType = (typeof(myClass));
PropertyInfo[] PropertyInfoArray = myType.GetProperties(
BindingFlags.Public |
BindingFlags.Instance);
return PropertyInfoArray;
}
2)Now, I'd like to set up the value of each one depending on the index this way
public void UpdateProperty(MyClass instanceOfMyClass, string valueToUpdate, int index)
{
//TODO:
//1. Get an individual property from the GetPropertyOfMyClass() using index
//2. Update the value of an individual property of the instanceOfMyClass
}
I'd like to be able to call UpdateProperty from a Controller like this:
UpdateProperty(instanceOfMyClass, valueToUpdate, indexOfTheProperty);
Honestly, I do not know how to involve the instanceOfMyClass in the game as GetProperty only plays with myClass.
Since I saw that I can use Name, PropertyType, ... to get information on the property. So, I've tried also GetPropertyOfMyClass()[index].SetValue(...), but I was lost in the arguments of its constructor, so I abandoned.
What I want is to be able to update the value of a property in my collection just by using the index.
Thanks for helping
Your guess was correct. You use SetValue() to update the value - this is how to do it:
GetPropertyOfMyClass()[index].SetValue( instanceOfMyClass, valueToUpdate, null);
The last argument can be null:
Optional index values for indexed properties. This value should be null for non-indexed properties.
Related
With arrays you can use a subscript to access Array Elements directly. You can read or write to them. With Sets I am not sure of a way to write its Elements.
For example, if I access a set element matching a condition I'm only able to read the element. It is passed by copy and I can't therefore write to the original.
For example:
columns.first(
where: {
$0.header.last == Character(String(i))
}
)?.cells.append(value: addValue)
// ERROR: Cannot use mutating member on immutable value: function call returns immutable value
You can't just change things inside a set, because of how a (hash) set works. Changing them would possibly change their hash value, making the set into an invalid state.
Therefore, you would have to take the thing you want to change out of the set, change it, then put it back.
if var thing = columns.first(
where: {
$0.header.last == Character(String(i))
}) {
columns.remove(thing)
thing.cells.append(value: addValue)
columns.insert(thing)
}
If the == operator on Column doesn't care about cells (i.e. adding cells to a column doesn't suddenly make two originally equal columns unequal and vice versa), then you could use update instead:
if var thing = columns.first(
where: {
$0.header.last == Character(String(i))
}) {
thing.cells.append(value: addValue)
columns.update(thing)
}
As you can see, it's quite a lot of work, so maybe sets aren't a suitable data structure to use in this situation. Have you considered using an array instead? :)
private var _columns: [Column]
public var columns : [Column] {
get { _columns }
set { _columns = Array(Set(newValue)) }
// or any other way to remove duplicate as described here: https://stackoverflow.com/questions/25738817/removing-duplicate-elements-from-an-array-in-swift
}
You are getting the error because columns might be a set of struct. So columns.first will give you an immutable value. If you were to use a class, you will get a mutable result from columns.first and your code will work as expected.
Otherwise, you will have to do as explained by #Sweeper in his answer.
I have tried the sorting with custom pattern. But as it returns an array. It's not helpful.
As I need the return type to be Results.
Ex: Consider following:
class A:Object {
dynamic var name: String = "abc"
dynamic var isStrong: Bool = false
}
Now how can I sort the above which will produce Results
I did try
realm.objects(a.self).sorted({ (o1, o2) -> Bool in
return o1.isStrong && !o2.isStrong
})
This produces a sorted array. But I need a realmResults object.
Any kind of help is apreiciated.
Thank you. :)
You can use a bool property for sorting a Results instance, but you cannot implement a custom sort function that would return Results. Results only supports sorting based on instance properties of the class or based on several instance properties if you add them to a SortDescriptor.
Even though you cannot define custom sorting logic, it seems that your current logic only implements a descending sort based on a single bool property, so you can achieve the same results using Realm's built in sorted(byKeyPath:,ascending:) method.
realm.objects(A.self).sorted(byKeyPath: "isStrong",ascending: false)
I have a object property in my Class which is private and marked as read-only.
private var readOnlyObj:Object;
I can only access it with a get method:
public function get readOnly(){ return readOnlyObj }
I can access it by:
var objClass = new MyClass();
trace(objClass.readOnly)
And if i'll try to modify it:
objClass.readOnly = new Object();
I'll get an error:
Error# Property is read only.
Now my question is:
How do I set the properties of my readOnlyObj as read-only?
If I have set the object in the constructor:
readOnlyObj["property1"] = 0;
And modify that property by:
objClass.readOnly["property1"] = 2;
It is valid. I want set the property1 to a read-only property. Is this possible? Thank You!
You can do this by returning a duplicate of the original object and not the object itself.
The transform properties of DisplayObjects work like this: you can get the object property from a get function and can modify the object, but such modification has no effect until you pass the modified object back to the set function.
In your case, there's no way to give the object back (no setter) and by returning a copy (commonly called 'clone') from the getter, there is no way to modify the object property from outside, because the returned reference reference the newly created independent clone, essentially making the internal object constant.
What you are asking is not possible and only yield the answer "no" if on the other hand you asked about how to achieve that functionality then there would be a few answer possible.
First of all given your code and the problem at hand it is clear that you misunderstand the class scope. You set:
private var readOnlyObj:Object;
As read only while it's really not the object you want to protect, it's its properties. So readOnlyObj should really not even be visible and accessible.
Now that readOnlyObj is private and not accessible, you can put together a simple method to retrieve properties:
public function getProperty(name:String):*
{
if(readOnlyObj[name] != undefined)
{
return readOnlyObj[name];
}
return null;
}
It might also be useful to know how to put together a public setter that cannot be used externally.
Create an internal Boolean variable (only with true package), then internally set that variable to true before setting the property then set it back to false. Since externally that boolean cannot be set you end up with a public setter that cannot be used externally.
internal var allowSetter:Boolean;
public function set whatever(value:*):void
{
if(allowSetter)
{
//set property ect...
allowSetter = false;
}
}
You can't really do this, at least in the way you describe. You can of course make your readOnly object a custom class instance that only has read-only properties, but you can't freeze a dynamic Object instance.
I have created a multifield custom widget having two fields with names ./urlLink and ./urlText.
Now i m trying to fetch the values from widget into the component's jsp with following code
String property = properties.get("./urlLink",String[].class);
for(String value: property ) {
out.print(value);
}
out.print(property);
But i am not able to get its value instead i m getting error.
If you're getting a property and it contains a string value, you need to use the method getString() - that way when you have the property, you can set the string to the value by doing something like this:
Property property = properties.get("./urlLink",String.class);
String value = property.getString();
Just a side note, if your return is supposed to be a string array, your type that you're putting the values in should be a string array.
String[] value
Check out the documentation on day.com for Properties and getting the values inside them.
Looks like a typo: you don't prefix a property name with .\ when accessing it.
My guess is you got a NullPointerException, right? That's because there's no ./urlLink property in the value map (properties). You should check against that anyway (so that it's not thrown on a fresh page with no content).
If that doesn't help -- double check that you have the properties in the content (call your page with .xml or .infinite.json extensions, and then double check if you can read them as plain strings (you should be able to -- CRX does some magic, smart type conversions).
It's good to register custom xtype as :
// registering the custom widget with the name dualfield
CQ.Ext.reg("dualfield", CQ.Ext.form.DualField);
Then u can easily fetch the value as :
String[] data = properties.get("multi",String[].class);
Here multi is the name of widget having multifield as xtype
I have two tables in my entity framework, objects, and parameters which have a foreign key pointing to the object to which they belong. I want to populate a tree with all the attributes of a certain object. So in order to find those I want to do this:
String parentObject = "ParentObjectName";
var getAttributes = (from o in myDB.ATTRIBUTE
where o.PARENT_OBJECT == parentObject
select o);
However when I try to do this I get an error saying it cannot convert from type OBJECT to string, even though in the database this value is stored as a string. I have a workaround where I get an instance of the parentObject, then go through every attribute and check whether it's parent_object == parentObjectInstance, but this is much less efficient than just doing 1 query. Any help would be greatly appreciate, thanks!
Well, PARENT_OBJECT.ToString() can't be called (implicitly or explicitly) in L2E, but if it just returns a property, you can look at that directly:
String parentObject = "ParentObjectName";
var getAttributes = (from o in myDB.ATTRIBUTE
where o.PARENT_OBJECT.NAME == parentObject
select o);
...note the .NAME
Try this:
String parentObject = "ParentObjectName";
var getAttributes = (from o in myDB.ATTRIBUTE
where o.PARENT_OBJECT.ToString() == parentObject
select o);