I am a bit confused by one expression:
var nodes:Array = new Array();
for (var i:int = 0; i<=3; i++)
{
var node:Node = new Node(i)
nodes.push(node);
}
trace(nodes[0].id + ":" + nodes[1].id);
Returned me 0:0 instead of 0:1 as I expected.
public class Node
{
public var id:int;
public function Node(id:int)
{
id = id
}
}
How this can be explained?
You are setting the argument called id equal to itself, which is clearly not the intended behavior.
When there are instance variables that have the same names as arguments, you need to be explicit about which variable you wish to set:
public function Node(id:int) {
this.id = id;
}
This would work too:
public function Node(an_id:int) {
id = an_id; //here it implicitly assigns the instance variable
}
Simple, but very very hard to spot when you are in the middle of it: The constructor in your node class needs to look like this instead:
public function Node(id:int)
{
this.id = id
}
When you omit the "this" the temporary variable id gets assigned to itself, hence the '0' in the output.
My first guess:
this.id = id instead of id = id
You need to call your object var implicitly
Related
I am trying to pass a variable from a method in my Controller to a method in a Model. Since the method in the Model takes one argument (which was designed earlier), I cannot pass my variable as an argument to the method in the Model. And also, the method in this Model is called by other controllers too, so if I change the argument, I have to change all the controllers too, which would be a tedious task.
What I have been trying so far is- I created one MyVariableClass and declared a property. Then I instantiated that class and set the property string to the variable that I wanted to pass. Now, in my Model's method, I instantiated the same MyVariableClass again, but when I did that, the value of the variable was set to null. The code I have right now is -
public ActionResult ItemInformation( string id)
{
//Pass a string to MyVariable
MyVariableVClass params = new MyVariableClass();
params.myVariable = "abc";
//This is what My Model is taking as an argument(id), and I don't want to
//pass mYvariable along with that argument because it will break other controllers
// too which calls this method
var itemInformation = _repository.GetItemInformation(id);
return View(itemInformation);
}
and MyVariableClass
public class MyVariableClass
{
public string myVariable { get; set; }
}
and the method in My Model
public IList<Items> GetItemInformation(string itemId)
{
MyVariableClass webType = new MyVariableClass();
var _params = webType.myVariable;
//Check this variable and perform database query
if (_params =="this")
{
var query = myFirstQuery;
}
else
{
var query = mySecondQuery;
}
//return ....
}
Anybody has solution to this? Thanks in Advance!
Any reason why subclassing your model and overriding the GetItemInformation method wouldn't work? Or, even easier, why not just overload the GetItemInformation method with one that takes two strings? Your other controllers can still use the one that only takes a single string.
public IList<Items> GetItemInformation(string itemId, MyVariableClass webType)
{
var _params = webType.myVariable;
//Check this variable and perform database query
if (_params == "this")
{
var query = myFirstQuery;
}
else
{
var query = mySecondQuery;
}
//return ....
}
public IList<Items> GetItemInformation(string itemId)
{
MyVariableClass fauxType = new MyVariableClass();
fauxType.myVariable = "not this";
return GetItemInformation(itemId, fauxType);
}
Try using session variable.
I have two questions regarding the Flex combo box.
The string representing the function name will be read from xml # run time.
var combo:ComboBox = new ComboBox();
combo.labelFunction = "functionName";
How can I achieve this?
So the first name, which is to be displayed in the combo box, can be only retrieved by accessing another DTO, called person and then its first name.
var combo:ComboBox = new ComboBox();
combo.labelField= "person.firstName";
My class looks like this,
public class Test
{
public var person:PersonDTO;
}
public class PersonDTO
{
public var firstName:String;
}
Is it possible to access any multi-level text using the combo box label field ?
You need to pass the function not the name.
Doing this
combo.labelFunction = "functionName";
Is passing a string.
The only work around I can think of is to make a switch statement with one case for each function you may have. Then call that with "case" from within your xml.
switch( xml.#labelfunction ){
case 'func1':
combo.labelFunction = this.func1;
break;
case 'func2':
combo.labelFunction = this.func2;
break;
}
Its hacky but should work.
ad 1) labelFunction
Calling functions when you know only the name as String is quite easy. The following snippets shows how you can execute a function that is a member of the same class. In case you need to call a function from another class replace this with the according variable name.
private function comboBox_labelFunction(item:Object):String
{
var functionName:String = myXml.#labelFunctionName;
return this[functionName](item);
}
ad 2) labelField
It's normally not possible to use "person.firstName" as labelField. However, you should be able use it within your labelFunction. Something like this should work...
private function comboBox_labelFunction(item:Object):String
{
var labelField:String = "person.firstName";
var attributeNames:Array = labelField.split(".");
for each (var attributeName:String in attributeNames)
{
if (item && item.hasOwnProperty(attributeName))
item = item[attributeName];
else
return null;
}
return item;
}
I have many Flex objects like this one:
public class MyData {
public var time: Date;
public var label: String;
}
I am populating this object from a DB record retrieved via AMF that looks something like this:
{
label: "Label",
incident: "2009-08-15 11:12:14.12233"
}
I want to write a generic value mapper for these object that, given a target object (instance of MyData here) and an input record, will be able to tell that MyData.time is a Date field and perform type mapping automatically. Something like this:
function map(obj, targetType): * {
var newInstance: * = new targetType();
for (var property: String in obj) {
if (getPropertyType(targetType, property) == Date) {
newInstance[property] = parseDate(obj[property]);
}
else {
newInstance[property] = obj[property];
}
}
}
function getPropertyType(type_var: Class, property: String): Class {
// .. this is what I have no idea how to do
}
Can someone fill in the blank here?
You possibly need something like describeType. And maybe you need to use getDefinitionByName() if you want to make to a real object. So something like this for the contents of your function:
var typeXml:XML = describeType(type_var[property]);
return getDefinitionByName(typeXml.type[0].#name);
I haven't compiled it. Just throwing it out there to see if it helps.
You can use the 'is' operator to check the type of an object.
The is operator
function map(obj, targetType): * {
var newInstance: * = new targetType();
for (var property: String in obj) {
if (obj[property] is Date) {
newInstance[property] = parseDate(obj[property]);
}
else {
newInstance[property] = obj[property];
}
}
}
hth
Koen
If you need to map an Object variable to a variable class as MyData you can do the following
public class MyData
{
public var time: Date;
public var label: String;
function map(obj:Object):void
{
for (var property: String in obj)
{
this[property] = obj[property];
}
}
}
Note: The object obj must contain the exact "time" and "label" properties.
Hope it solves your problem
I've got two classes.
public class Class1 {
public string value {get;set;}
}
public class Class2 {
public Class1 myClass1Object {get;set;}
}
I've got an object of type Class2. I need to use reflection on Class2 to set the value property... i.e, if I were doing it without reflection, this is how I would go about it:
Class2 myObject = new Class2();
myObject.myClass1Object.value = "some value";
Is there a way to do the above, while using reflection to access the property "myClass1Object.value" ?
Thanks in advance.
Basically split it into two property accesses. First you get the myClass1Object property, then you set the value property on the result.
Obviously you'll need to take whatever format you've got the property name in and split it out - e.g. by dots. For example, this should do an arbitrary depth of properties:
public void SetProperty(object source, string property, object target)
{
string[] bits = property.Split('.');
for (int i=0; i < bits.Length - 1; i++)
{
PropertyInfo prop = source.GetType().GetProperty(bits[i]);
source = prop.GetValue(source, null);
}
PropertyInfo propertyToSet = source.GetType()
.GetProperty(bits[bits.Length-1]);
propertyToSet.SetValue(source, target, null);
}
Admittedly you'll probably want a bit more error checking than that :)
I was looking for answers to the case where to Get a property value, when the property name is given, but the nesting level of the property is not known.
Eg. if the input is "value" instead of providing a fully qualified property name like "myClass1Object.value".
Your answers inspired my recursive solution below:
public static object GetPropertyValue(object source, string property)
{
PropertyInfo prop = source.GetType().GetProperty(property);
if(prop == null)
{
foreach(PropertyInfo propertyMember in source.GetType().GetProperties())
{
object newSource = propertyMember.GetValue(source, null);
return GetPropertyValue(newSource, property);
}
}
else
{
return prop.GetValue(source,null);
}
return null;
}
public static object GetNestedPropertyValue(object source, string property)
{
PropertyInfo prop = null;
string[] props = property.Split('.');
for (int i = 0; i < props.Length; i++)
{
prop = source.GetType().GetProperty(props[i]);
source = prop.GetValue(source, null);
}
return source;
}
Hi i need to make a VectorIterator, so i need to accept a Vector with any type. I am currently trying to define the type as * like so:
var collection:Vector.<*> = new Vector<*>()
But the compiler is complaining that the type "is not a compile time constant". i know a bug exists with the Vector class where the error reporting, reports the wrong type as missing, for example:
var collection:Vector.<Sprite> = new Vector.<Sprite>()
if Sprite was not imported, the compiler would complain that it cannot find the Vector class. I wonder if this is related?
So it looks like the answer is there is no way to implicitly cast a Vector of a type to valid super type. It must be performed explicitly with the global Vector.<> function.
So my actual problem was a mix of problems :)
It is correct to use Vector. as a generic reference to another Vector, but, it cannot be performed like this:
var spriteList:Vector.<Sprite> = new Vector.<Sprite>()
var genericList:Vector.<Object> = new Vector.<Object>()
genericList = spriteList // this will cause a type casting error
The assignment should be performed using the global Vector() function/cast like so:
var spriteList:Vector.<Sprite> = new Vector.<Sprite>()
var genericList:Vector.<Object> = new Vector.<Object>()
genericList = Vector.<Object>(spriteList)
It was a simple case of me not reading the documentation.
Below is some test code, I would expect the Vector. to cast implicitly to Vector.<*>.
public class VectorTest extends Sprite
{
public function VectorTest()
{
// works, due to <*> being strictly the same type as the collection in VectorContainer
var collection:Vector.<*> = new Vector.<String>()
// compiler complains about implicit conversion of <String> to <*>
var collection:Vector.<String> = new Vector.<String>()
collection.push("One")
collection.push("Two")
collection.push("Three")
for each (var eachNumber:String in collection)
{
trace("eachNumber: " + eachNumber)
}
var vectorContainer:VectorContainer = new VectorContainer(collection)
while(vectorContainer.hasNext())
{
trace(vectorContainer.next)
}
}
}
public class VectorContainer
{
private var _collection:Vector.<*>
private var _index:int = 0
public function VectorContainer(collection:Vector.<*>)
{
_collection = collection
}
public function hasNext():Boolean
{
return _index < _collection.length
}
public function get next():*
{
return _collection[_index++]
}
}
[Bindable]
public var selectedItems:Vector.<Category>;
public function selectionChange(items:Vector.<Object>):void
{
selectedItems = Vector.<Category>(items);
}
I believe you can refer to an untyped Vector by just calling it Vector (no .<>)
With Apache Flex 4.11.0, you can already do what you want. It might have been there since 4.9.0, but I have not tried that before.
var collection:Vector.<Object> = new Vector.<Object>()
maybe?
But i'm just speculating, haven't tried it.
var collection:Vector.<Object> = new Vector.<Object>()
but only on targeting flash player 10 cs4