Here's some code,
k.Bind<IGame>().To<Game>().Named("A")
.WithConstructorArgument("ColorChoiceCount", 12);
iGame = k.Get<IGame>("A");
((Game)iGame).SelectedColor = new GameColor(System.Drawing.Color.Red);
iGame = k.Get<IGame>("A");
On the first iGame = k.Get<IGame>("A"); I get a new instance of Game.
Next line: I change one of it's properties.
Next line (iGame = k.Get<IGame>("A"); again) I get a new instance again.
What I would like is to be able to retrieve instances I've already used.
But I'm totally new to this kind of tools so I guess I'm missing something.
Thank you if you can help me.
You need to specify the lifetime of your object - by default the container will create a new instance.
The available methods are as follows:
InScope
InTransientScope
InThreadScope
InSingletonScope
InRequestScope
http://blog.bobcravens.com/2010/03/ninject-life-cycle-management-or-scoping/
You probably want a singleton (single instance of the game):
k.Bind<IGame>().To<Game>().InSingletonScope().Named("A")
.WithConstructorArgument("ColorChoiceCount", 12);
Related
Just for my curiosity (and future knowledge), how does Entity Framework 5 decide when to create a new object vs. referencing an existing one? I might have just been doing something wrong, but it seems that every now and then if I do something along the lines of:
using (TestDB db = new TestDB())
{
var currParent = db.Parents.Where(p => p.Prop == passedProp).FirstOrDefault();
if(currParent == null) {
Parent newParent = new Parent();
newParent.Prop = passedProp;
currParent = newParent;
}
//maybe do something to currParent here
var currThing = db.Things.Where(t => t.Prop == passedPropTwo).FirstOrDefault();
currThing.Parent = currParent;
db.SaveChanges();
}
EF will create a new Parent in the database, basically a copy of the currParent, and then set the Parent_ID value of currThing to that copy. Then, if I do it again (as in, if there's already two of those parents), it won't make a new Parent and instead link to the first one. I don't really understand this behavior, but after playing around with it for a while something like:
using (TestDB db = new TestDB())
{
var currParent = db.Parents.Where(p => p.Prop == passedProp).FirstOrDefault();
if(currParent == null) {
Parent newParent = new Parent();
newParent.Prop = passedProp;
currParent = newParent;
}
//maybe do something to currParent here
var currThing = db.Things.Where(t => t.Prop == passedPropTwo).FirstOrDefault();
currThing.Parent = db.Parents.Where(p => p.ID == currParent.ID).First();
db.SaveChanges();
}
seemed to fix the problem. Is there any reason this might happen that I should be aware of, or was there just something weird about the way I was doing it at the time? Sorry I can't be more specific about what the exact code was, I encountered this a while ago and fixed it with the above code so I didn't see any reason to ask about it. More generally, how does EF decide whether to reference an existing item instead of creating a new one? Just based on whether the ID is set or not? Thanks!
If your specific instance of your DBContext provided that specific instance of that entity to you, then it will know what record(s) in the database it represents and any changes you make to it will be proper to that(those) record(s) in the database. If you instantiate a new entity yourself, then you need to tell the DBContext what exactly that record is if it's anything but a new record that should be inserted into your database.
In the special scenario where you have multiple DBContext instances and one instance provides you this entity but you want to use another instance to work with and save the entity, then you have to use ((IObjectContextAdapter)firstDbContext).ObjectContext.Detach() to orphan this entity and then use ((IObjectContextAdapter)secondDbContext).ObjectContext.Parents.Attach() to attach it (or ApplyChanges() if you're also editing it - this will call Attach for you).
In some other special scenarios (your object has been serialized and/or you have self-tracking entities), some additional steps may be required, depending on what exactly you are trying to do.
To summarize, if your specific instance of your DBContext is "aware" of your specific instance of an entity, then it will work with it as if it is directly tied to that specific row in the database.
I have created a PHP service in Flex Mobile and binded the result with a List. I want to sort the records from the service based on some calculation on data fields. So, is it possible to perform operations on the resultset from the PHP service ?
Detailed question:
I have created the php service through the built in tool in Flash Builder 4.6. I also had bind the service with a List in my view. (Again using GUI controls). Now I want to rearrange the items in the list based on distance from the current location and coordinates from the rows returned by the service. So the approach I was thinking was to, get the content from the service. Extract lat,lon and calculate the distance. Then update the list again.
I tried the following line in a function:
getAllplacesResult.lastResult[1].lon // lon is a column in the table.
But it returns a blank. Is their a more sane or easier way to do this ?
The better way is to assign it on an Arraycollection and manipulate data from there.
<mx:ArrayCollection id="myAC" source="{ArrayUtil.toArray(myRO.getAllplacesResult.lastResult)}" />
Make sure you bind myAC to your List.
Sort it the way you want to:
var collection:ArrayCollection = new ArrayCollection();
var s:Sort = new Sort();
s.fields = [new SortField("lat"), new SortField("lon")];
s.compareFunction = myCompareFunction;
collection.sort = s;
collection.refresh();
private function myCompareFunction(a:Object, b:Object, fields:Array = null):int {
...
}
Also, AS3 is 0 based index. 1 will actually give you the second row (or throw out of range exception)
Hey folks, i ve got this issue implementing the Factory method.
Following is the snippet of the the main chart class which calls ChartFactory's method to attain the proper object. I Type Cast chartobject so as to be able to call the Show method;i m apprehensive about that as well.
container = new VBox();
container.percentWidth = 100;
container.percentHeight = 100;
super.media.addChild(container);
chartObject = new ChartBase();
chartObject = ChartFactory.CreateChartObject(chartType);
IChart(chartObject).Show(o);
container.addChild(chartObject);
legend = new Legend();
legend.dataProvider = IChart(chartObject);
container.addChild(legend);
Following is the snippet of ChartFactory's method:
public static function CreateChartObject(subType:String):ChartBase
{
switch(subType)
{
case ChartFactory.AREA_CHART:
return new AreaCharts();
break;
case ChartFactory.COLUMN_CHART:
return new ColumnCharts();
break;
case ChartFactory.PIE_CHART:
return new PieCharts();
break;
default:
throw new ArgumentError(subType + ": Chart type is not recognized.");
}
}
And following is Show method of one of the several Charts type classes: AreaCharts, PieCharts etc. All of which implements IChart Interface.
public function Show(o:ObjectProxy):void
{
var grids:GridLines;
var stroke:SolidColorStroke;
var horizontalAxis:CategoryAxis;
var verticalAxis:LinearAxis;
var horizontalAxisRenderer:AxisRenderer;
var verticalAxisRenderer:AxisRenderer;
grids = new GridLines();
if(WidgetStylesheet.instance.LineChart_ShowGrid)
grids.setStyle("gridDirection", "both");
else
grids.setStyle("gridDirection", "");
stroke = new SolidColorStroke(WidgetStylesheet.instance.LineChart_GridLineColor, WidgetStylesheet.instance.LineChart_GridLineThickness);
grids.setStyle("horizontalStroke", stroke);
grids.setStyle("verticalStroke", stroke);
horizontalAxis = new CategoryAxis();
horizontalAxis.categoryField = o.LargeUrl.Chart.xField;
horizontalAxis.title = o.LargeUrl.Chart.xAxisTitle.toString();
verticalAxis = new LinearAxis();
verticalAxis.title = o.LargeUrl.Chart.yAxisTitle.toString();
horizontalAxisRenderer = new AxisRenderer();
horizontalAxisRenderer.axis = horizontalAxis;
horizontalAxisRenderer.setStyle("tickLength", 0);
horizontalAxisRenderer.setStyle("showLine", false);
horizontalAxisRenderer.setStyle("showLabels", true);
horizontalAxisRenderer.setStyle("fontSize", WidgetStylesheet.instance.ComputeChartAxisFontSize(o.HeadlineFontSize));
verticalAxisRenderer = new AxisRenderer();
verticalAxisRenderer.axis = verticalAxis;
verticalAxisRenderer.setStyle("tickLength", 0);
verticalAxisRenderer.setStyle("showLine", false);
verticalAxisRenderer.setStyle("fontSize", WidgetStylesheet.instance.ComputeChartAxisFontSize(o.HeadlineFontSize));
this.series = this.m_createSeries(o);
this.horizontalAxis = horizontalAxis;
this.horizontalAxisRenderers = [horizontalAxisRenderer];
this.verticalAxis = verticalAxis;
this.verticalAxisRenderers = [verticalAxisRenderer];
this.backgroundElements = [grids];
}
I'm afraid that there is more than one issue with this code. Unfortunately it is not obvious why your chart doesn't show up so you may apply some of advices below and use debugger to analyse the issue.
There is no point in creating ChartBase instance if you are going to change value of chartObject reference in the next line
chartObject = new ChartBase();
chartObject = ChartFactory.CreateChartObject(chartType);
If the API of your charts is IChart your factory should return IChart instead of casting.
public static function CreateChartObject(subType:String):IChart
Make sure that you are returning instances of the correct class from the factory. i.e. that you are returning your subclass of standard PieChart. Generally it's not the best idea to extend the class keeping the same name and just changing the package.
Once again, if you are not sure if the program enters some function use the Flash Builder debugger to check this. I can't imagine development without debugger.
Some thoughts:
you call the Show method, pass it some object but nowhere in that method is any child added to a displayObject. What exactly is Show supposed to do?
a lot of member variables in your classes start with UpperCase. The compiler can easily confuse those with class names, in case your classes are named the same. Bad practice to start variable and function names with capitals.
If your casting an instance to another class or interface fails, you will get a runtime error. Those are easy to debug using the Flash Builder debugger.
Hey ppl..
i found out wat wnt wrng..as olwys it wa "I".
I ve a habit of mkin mock ups secluded from the main project n dn integrate it. So in mock up i hd used an xml whch hd a format slightly diff dn d one being used in the main project.
N i hd a conditional chk to return from the prog if certain value doesnt match, n due to faulty xml i did'nt.
So this more a lexical error than a logical one.
Sorry n Thanx evryone for responding.
What I'm doing NOW:
Often multiple instances of the view component would be used in multiple places in an application. Each time I do this, I register the same mediator with a different name.
When a notification is dispatched, I attach the name of the mediator to the body of the notification, like so:
var obj:Object = new Object();
obj.mediatorName = this.getMediatorName();
obj.someParameter = someParameter;
sendNotification ("someNotification", obj);
Then in the Command class, I parse the notification body and store the mediatorName in the proxy.
var mediatorName:String = notification.getBody().mediatorName;
var params:String = notification.getBody().someParameter;
getProxy().someMethod(params, mediatorName);
On the return notification, the mediatorName is returned with it.
var obj:Object = new Object();
obj.mediatorName = mediatorName;
obj.someReturnedValue= someReturnedValue;
sendNotification ("someReturnedNotification", obj);
In the multiple mediators that might be watching for "someReturnedNotification," in the handleNotification(), it does an if statement, to see
if obj.mediatorName == this.getMediatorName
returns true. If so, process the info, if not, don't.
My Question is:
Is this the right way of using Multiton PureMVC? My gut feeling is not. I am sure there's a better way of architecting the application so that I don't have to test for the mediator's name to see if the component should be updated with the returned info.
Would someone please help and give me some direction as to what is a better way?
Thanks.
I checked with Cliff (the puremvc.org guy) and he said it's fine.
So I'm starting out with EF on my website (C#) and Ive run into a bit of a snag. A user can either create or modify data and they will do that with the selection screen (page 1). If a user selects to create new data, I will perform the following code:
Program newProg = new Program();
using (DatabaseEntities context = new DatabaseEntities())
{
Guid id = new Guid(list.SelectedValue);
var itemString = from item in context.Set where item.Id == id select item;
Item selectedItem = itemString.ToList()[0];
newProg.Items.Add(selectedItem);
context.AddToProgramSet(newProg);
context.Detach(newProg);
}
Pretty much creating a new instance of the 'Program' which will be passed along each user control until the user is ready to submit to the database. At that point the following code will be executed:
using (DatabaseEntities context = new DatabaseEntities())
{
context.AddToProgramSet(this.SummaryControl.SelectedProgram);
context.SaveChanges();
}
Unfortunately when I get there, I receive the following message:
The object cannot be added to the ObjectStateManager because it already has an EntityKey. Use ObjectContext.Attach to attach an object that has an existing key.
at this line:
context.AddToProgramSet(this.SummaryControl.SelectedProgram);
Also, when I add the following line prior to the previous:
context.Attach(this.SummaryControl.SelectedProgram);
I get this error:
An object with a null EntityKey value cannot be attached to an object context.
Any help would be greatly appreciated. Thanks.
The root cause of this error is that you are attempting to add an Entity as a new Entity that already has its primary key set.
At what point do you add the Entities to your SummaryControl? Your first code snippet shows you adding the Entity:
...
newProg.Items.Add(selectedItem);
context.AddToProgramSet(newProg);
context.Detach(newProg);
...
Then you appear to add it again:
using (DatabaseEntities context = new DatabaseEntities())
{
context.AddToProgramSet(this.SummaryControl.SelectedProgram);
context.SaveChanges();
}
If newProg and this.SummaryControl.SelectedProgram are the same Entity, you've attempted to add it twice. Remove the context.AddToProgramSet(newProg); from the first snippet, do you work on the Entity, then add it to the ProgramSet.
Dave is right that the root cause is that the entity already has a primary key.
One thing that you do not show in your code is how:
Program newProg = new Program();
Becomes:
this.SummaryControl.SelectedProgram
One way that you could fix it is by saving newProg to the database before you start adding Items to it.