I have an UICollectionView with AllowsMultipleSelection = true, and I binded SelectionChangedCommand of MvxCollectionViewSource, but SelectionChangedCommand triggers only on selection. How can I bind deselection? Is there anything like DeselectionChangedCommand?
when item deselected, isn't SelectionChangedCommand firing with a null ?
if it doesn't you could subscribe to the selection event of the control in the controller and on event handler call the SelectionChangedCommand with null
Thank you for answer, but it isn't firing with a null value on deselected. But I found solution:
public class MvxCollectionViewDSSource: MvxCollectionViewSource
{
public MvxCollectionViewDSSource(UICollectionView collectionView)
: base(collectionView)
{
}
public MvxCollectionViewDSSource(UICollectionView collectionView,
NSString defaultCellIdentifier)
: base(collectionView, defaultCellIdentifier)
{
}
public override void ItemDeselected(UICollectionView collectionView, NSIndexPath indexPath)
{
var item = GetItemAt(indexPath);
var command = SelectionChangedCommand;
if (command != null)
command.Execute(item);
}
}
Related
This weekend a lot of struggle with a View Component.
I try to add a dropdownlist that does an auto postback onchange. This dropdownlist is on a view component.
I have 2 problems:
I don't get the asp-page-handler after the post, does it work like I implemented it on the form-tag?
Post calls method public void OnPost on razor page containing view
component. I would think it would be better to have a method on the
View Component like OnChangeProject?
The code of my View (View Component):
<form asp-page-handler="ChangeProject" method="post">
#Html.AntiForgeryToken()
#Html.DropDownList("id", new SelectList(Model, "Id", "Id"), new { onchange = "this.form.submit()" })
</form>
Thanks in advance!!
I exprienced the same problem and the way i fixed it is already answered in your question.
The form call is made at the page where you got your View Component embedded. I don't think it would be even possible to call a handler in your View Component with asp-page-handler as this is Razor Pages tag helper.
The way i got it work is simply putting the page-handler method on the PageModel that is embedding the View Component. In your case you can simply implement this handler on your Razor Page:
public IActionResult OnPostChangeProject()
{
// ... do Something
}
I don't know though how it would work to trigger a controller method in your View Component. Possibly create a new Controller class and route to it with asp-controller and asp-action in your form tag.
You should remember that the Page handlers could be viewed as convenience methods.
All the ASP.Net Core framework does is looks at the Query string parameters and Form data and translates it into Page handler calls.
And even though the Handlers are not available in View Components or Partial Views you still can get access to all the required ingredients by injecting IHttpContextAccessor into the View.
It will provide you with HttpContext.Request which contains both the Query and the Form properties.
You can then create your own Handler mapper. Here is one, for example:
public class HandlerMapping
{
public string Name { get; set; }
public System.Delegate RunDelegate { get; set; }
public HandlerMapping(string name, Delegate runDelegate)
{
RunDelegate = runDelegate;
Name = name;
}
}
public class PartialHandlerMapper
{
IHttpContextAccessor _contextAccessor;
public PartialHandlerMapper(IHttpContextAccessor contextAccessor)
{
_contextAccessor = contextAccessor;
}
public void RouteHandler(List<HandlerMapping> handlerMappings, string PartialDescriminatorString = null)
{
var handlerName = _contextAccessor.HttpContext.Request.Query["handler"];
var handlerMapping = handlerMappings.FirstOrDefault(x => x.Name == handlerName);
if (handlerMapping != null)
{
IFormCollection form;
try
{
form = _contextAccessor.HttpContext.Request.Form;
}
catch
{
return;
}
if (!string.IsNullOrWhiteSpace(PartialDescriminatorString) && form[nameof(PartialDescriminatorString)] != PartialDescriminatorString)
return;
List<Object> handlerArgs = new List<object>();
var prmtrs = handlerMapping.RunDelegate.Method.GetParameters();
foreach (var p in prmtrs)
{
object nv = null;
var formValue = form[p.Name];
if (!StringValues.IsNullOrEmpty(formValue))
{
try
{
nv = TypeDescriptor.GetConverter(p.ParameterType).ConvertFromString(formValue);
}
catch (FormatException)
{
//throw new FormatException($"Could not cast form value '{formValue}' to parameter {p.Name} (type {p.ParameterType}) of handler {handlerName}. Make sure you use correct type parameter. ");
nv = Activator.CreateInstance(p.ParameterType);
}
catch (ArgumentException)
{
nv = Activator.CreateInstance(p.ParameterType);
}
}
else
nv = Activator.CreateInstance(p.ParameterType);
handlerArgs.Add(nv);
}
handlerMapping.RunDelegate.DynamicInvoke(handlerArgs.ToArray());
}
}
}
And inject it into the service container:
services.AddScoped<PartialHandlerMapper>();
And here is a shopping cart partial view code section example:
#inject ShoppingManager shoppingManager
#inject PartialHandlerMapper partialHandlerMappping
#{
string ToggleCartItemTrialUseHandler = nameof(ToggleCartItemTrialUseHandler);
string DeleteCartItemHandler = nameof(DeleteCartItemHandler);
List<HandlerMapping> handlerMappings = new List<HandlerMapping> {
new HandlerMapping (ToggleCartItemTrialUseHandler, (Guid? PicID, bool? CurrentValue) => {
if (PicID == null || CurrentValue == null)
return;
shoppingManager.UpdateTrial((Guid)PicID, !(bool)CurrentValue);
}),
new HandlerMapping (DeleteCartItemHandler, (Guid? PicID) => {
if (PicID == null)
return;
shoppingManager.RemoveProductFromCart((Guid)PicID);
})
};
partialHandlerMappping.RouteHandler(handlerMappings);
var cart = shoppingManager.GetSessionCart();
}
Form element example from the same view:
<td align="center" valign="middle">
<form asp-page-handler="#DeleteCartItemHandler">
<input name=PicID type="hidden" value="#i.PicID" />
<button>
Delete
</button>
</form>
</td>
Where #i is an Item in the shopping cart
It's possible to create a combo (Controller/ViewComponent) by decorating the controller with a ViewComponent(Name="myviewcomponent").
Then create the invokeasync as usual, but because the controller doesn't inherit from a ViewComponent, the return result would be one of the ViewComponent result (ViewViewComponentResult, et).
The form in the viewcomponent can then have a button with asp-controller/action tag helpers targetting the controller/action.
We are using some MT.D StringElements, and their Value Property is bound to properties in the ViewModel.
The initial value is correctly shown but when the ViewModel changes some values and triggers PropertyChanged then the StringElements contain the good value but the display is not refreshed.
If we scroll the Controller or touch the StringElement then it is refreshed: the correct value is displayed.
Do you have any idea?
This is our ViewController
public class ContactView : MvxDialogViewController
{
public override void ViewDidLoad()
{
base.ViewDidLoad();
var bindings = this.CreateInlineBindingTarget<ContactViewModel> ();
Root = new RootElement()
{
new Section()
{
new StringElement("Company Name").Bind(bindings, vm => vm.CompanyName)
}
}
}
}
This is our ViewModel (simplified)
public class ContactViewModel : MvxViewModel
{
private string companyName;
public string CompanyName{
get{return companyName;}
set{companyName = value; RaisePropertyChanged(() => CompanyName);}
}
public async Task Init(string id)
{
var contact = await someService.SomeMethodAsync();
CompanyName = contact.CompanyName;
}
}
I found two solutions to my problem:
If I use UIView.Transition to replace the content then, in the new View, nothing is refreshed when I change the ViewModel (unless I scroll or tap it) UNLESS if the ViewModel properties have some default value non null and non empty
If I don't transition but use another method like this one to replace the content:
Sample code
MasterNavigationController.PopToRootViewController(false);
MasterNavigationController.ViewControllers = new UIViewController[] { viewController };
In this case the content is replaced and the view is refreshed when a ViewModel property changes: everything works correctly in this case.
I tried a viewmodel like:
public class FirstViewModel
: MvxViewModel
{
private Timer _timer;
private int _count;
public FirstViewModel()
{
_timer = new Timer(DoThis, null, 1000, 1000);
}
private void DoThis(object state)
{
_count++;
TextProperty = _count.ToString();
}
private string _textProperty = "T";
public string TextProperty
{
get { return _textProperty; }
set { _textProperty = value; RaisePropertyChanged(() => TextProperty); }
}
}
with a dialog view defined like:
Root = new RootElement("Example Root")
{
new Section("Debut in:")
{
new EntryElement("Login", "Enter Login name").Bind(bindings, vm => vm.TextProperty)
},
new Section("Debug out:")
{
new StringElement("Value is:").Bind(bindings, vm => vm.TextProperty),
};
It worked fine - ticking up every second...
I have a navigation controller to show a list o item on table, then I need to touch an item a show the details of this item.
Here it's my code of how a fill the table:
public void SearchHotel (){
Hotel hotel = new Hotel();
var distribution = new HotelDistribution[]{new HotelDistribution(){ Adults = 1, Children = 0, ChildrenAges = new int[0]} };
var items = hotel.SearchHotels(Convert.ToDateTime("2013-08-08"),Convert.ToDateTime("2013-09-09 "),"(MIA)", distribution,"","","",0);
data = new List<DtoHotelinformation>();
foreach (var item in items)
{
DtoHotelinformation DtoHotelinformation = new DtoHotelinformation();
DtoHotelinformation.code = item.Code.ToString();
DtoHotelinformation.price = item.Price.ToString();
DtoHotelinformation.title = item.Name.ToString().ToTitleCase();
DtoHotelinformation.subtitle = item.Address.ToString();
DtoHotelinformation.rating = item.Rating.ToString();
DtoHotelinformation.imageUlr = item.ImageUrl;
data.Add(DtoHotelinformation);
}
hud.Hide(true);
hud.RemoveFromSuperview();
HotelSearchTable.Source = new HotelTableSource(data.ToArray());
HotelSearchTable.ReloadData();
}
Because I'm using storyboard to show the details view controller I have this code on my table source:
public override void RowSelected (UITableView tableView, NSIndexPath indexPath)
{
if (RowTouched != null) {
RowTouched (this, EventArgs.Empty);
}
tableView.DeselectRow (indexPath, true); // normal iOS behaviour is to remove the blue highlight
}
Back in to my viewcontroller I call the RowTouched to show the details controller like this:
public override void ViewDidAppear (bool animated) {
base.ViewDidAppear (animated);
SearchHotel ();
var source = new HotelTableSource(data.ToArray());
var detail = Storyboard.InstantiateViewController("HotelDetailScreen") as iPhoneHotelDetailViewController;
source.RowTouched += (sender, e) => {
this.NavigationController.PushViewController(detail, true);
};
HotelSearchTable.Source = source;
}
But I need to pass the information of the item touched on the table to show the details. I don't really don't know what do I have to do?
NOTE: I can't use PrepareForSegue because I don't have a segue between controllers.
Thanks in advance
If you want you can get a hold of your UINavigationController
from within your Row Selected event, inside of your Table Data Source.
From there you can push your new ViewController.
[indexPath.Row] in "Row_Selected" should tell you which element in your array or list, that the user has selected.
UINavigationController navcontroller =(UINavigationController)UIApplication.SharedApplication.Windows[0].RootViewController;
Passing data to an event handler is exatly what the EventArgs parameter is for.
Create a class that inherits from EventArgs and has properties for the data you need:
public class HotelSelectedEventARgs : EventArgs
{
public DTOHotelInformation HotelInfo { get; set; }
}
Then, when you call your handler in RowSelected, instead of passing an empty EventArgs, create an instance of your custom class and assign the selected data to the HotelInfo property.
In ActionScript 3, is there a clean way to define a function that accepts an optional boolean argument ? As you may know, this is invalid :
public function test(param:Boolean = null):void {
trace(param);
}
This triggers the following error: VerifyError: Error #1102: Illegal default value for type Boolean. Since, Boolean is a primitive, I guess it makes sense that it cannot be set to null. The only workaround I found is to cast the parameter to an object :
public function test(param:Object = null):void {
trace(Boolean(param));
}
However, this does not feel very clean, particularly if you are developing libraries. ASDoc will generate API documentation that says the expected parameter is an Object whereas what is really needed is a Boolean.
Is there a better approach ?
When you say optional, I assume that you mean if there isn't a value supplied then something different should happen compared to if you had a default value of true or false.
You could make your own object to handle the three states that you need and maintain code readability by using a class like this:
public class Condition
{
private var _value:* = null;
public function Condition(initial:* = null)
{
value = initial;
}
public function set value(n:*):void
{
if(_value === null || _value === false || _value === true)
{
_value = n;
}
}
public function get value():*{ return _value; }
}
And then your function could be:
function test(param:Condition = null):void
{
if(param && param.value != null)
{
trace(param.value);
}
}
test( new Condition() );
test( new Condition(true) );
As you said Boolean can not be set to null value.
Therefore, you should specify a default value that is either true or false.
public function test(param:Boolean = false):void {
trace(param);
}
But because you need the third case where nothing is set, one option could be to accept any Object but throw an exception if it is not null and not a boolean:
public function test(param:* = null):void
{
if (param != null)
{
if ((param == true) || (param == false))
{
trace(Boolean(param).toString());
}
else
{
throw new CustomError("param should be a boolean");
}
}
else
{
// Do nothing
}
}
Note that this solution also accept objects or primitives that can be compared to true or false such as 0, 1, or [].
From the good suggestions and discussion above I think that, in a library scenario and for simplicity's sake, the best way remains to type the parameter as Object with a default value of null but to request a Boolean in the API documentation :
/**
* #param param Boolean object or null
*/
public function test(param:Object = null):void {
trace(Boolean(param));
}
This allow the user of the library to pass a either a Boolean or nothing at all. Thanks everyone.
There was a tonne of discussion on my previous answer, but this is the correct way to have a function that accepts one of three states. My previous answer attempted to retain the use of a Boolean value like you were requesting, but that is not the right way to go about it.
Create a class that defines three values:
class State
{
public static const EMPTY:int = -1;
public static const FALSE:int = 0;
public static const TRUE:int = 1;
}
Your function will accept an int (the type of each of the three properties within your State class). It will deal with the three possible values. You can use concise commenting to notify the developer of what thee values the function is expecting, referencing the State class. The default value can be -1 aka State.EMPTY.
/**
* Function description.
* #param state One of three states, defined by State.
*/
function test(state:int = -1):void
{
switch(state)
{
case State.EMPTY:
// No value given.
break;
case State.TRUE:
// True.
//
break;
case State.FALSE:
// False.
//
break;
default:
throw new ArgumentError("Unsupported value for test()");
break;
}
}
I am trying to understand the way the AsyncToken works in actionscript. How can I call a remote service and ensure that a specific parameter is available in the result or fault event functions? I think it is the async functionality I want to use.
The following code will hopefully explain what I am trying to do. Feel free to modify the code block as your explanation.
Thanks.
public function testSerivceCall(data:Object, callBackCommand:String):void
{
// Assume callBackCommand == "FOO";
// How can I pass in callBackCommand as a parameter to the result or fault events?
// How do I create an async token here?
var remoteObject:RemoteObject;
remoteObject = new RemoteObject();
remoteObject.destination = "zend";
remoteObject.source = "MyService";
remoteObject.endpoint = "http://example.com/service";
remoteObject.test.addEventListener(ResultEvent.RESULT, _handleTestResult);
remoteObject.test.addEventListener(FaultEvent.FAULT, _handleTestFault);
remoteObject.test(data);
}
private function _handleTestResult( event:ResultEvent ) : void
{
// How do I get the async token value?
// How can I get the value of callBackCommand in this code block?
if (callBackCommand == "FOO")
{
// do something related to "FOO"
}
else
{
// do something else with the result event
}
}
private function _handleTestFault( event:FaultEvent ) : void
{
// How do I get the async token value?
// How can I get the value of callBackCommand in this code block?
}
An edit to make this question more clear:
Assume I make the following method call somewhere in my code:
testSerivceCall(personObject, "LoginCommand");
How do I get access to the actual string "LoginCommand" inside the _handleTestResult function block?
The reason I want to do this is because I want to dynamically call back certain functions and hand off the result data to specific commands that I know ahead of time when I am making the service call.
I am just having a time grokking the AsyncToken syntax and functionality.
I did not even need closures. I added a class as below which I called externally.
The call was like this:
public class MyClass
{
...
var adminServerRO:AdminServerRO = new AdminServerRO();
adminServerRO.testSerivceCall("FOO",cptyId);
}
public class AdminServerRO
{
private function extResult( event:ResultEvent, token:Object ) : void
{
//the token is now accessed from the paremeter
var tmp:String = "in here";
}
private function extFault( event:FaultEvent ) : void
{
var tmp:String = "in here";
}
public function testSerivceCall(callBackCommand:String, cptyId:String):void
{
var remoteObject:RemoteObject = new RemoteObject();
remoteObject.destination = "adminServer";
var token:AsyncToken = remoteObject.getCounterpartyLimitMonitorItemNode(cptyId);
token.addResponder(new AsyncResponder(extResult,extFault,cptyId));
}
}
While the accepted answer will accomplish what the original submitter wants it does not actually answer the question which was asked. An AsyncToken is created as a result of a remote method call and is accessible from the ResultEvent. Since AsyncToken is a dynamic class you can add whatever property to it that you want. The code below should demonstrate this:
public function testSerivceCall(data:Object, callBackCommand:String):void
{
var remoteObject:RemoteObject;
remoteObject = new RemoteObject();
remoteObject.destination = "zend";
remoteObject.source = "MyService";
remoteObject.endpoint = "http://example.com/service";
remoteObject.test.addEventListener(ResultEvent.RESULT, _handleTestResult);
remoteObject.test.addEventListener(FaultEvent.FAULT, _handleTestFault);
var token:AsyncToken = remoteObject.test(data);
token.callBackCommand = callBackCommand;
}
private function _handleTestResult( event:ResultEvent ) : void
{
if (event.token.callBackCommand == "FOO")
{
// do something related to "FOO"
}
else
{
// do something else with the result event
}
}
private function _handleTestFault( event:FaultEvent ) : void
{
//event.token.callBackCommand should be populated here too
}
If you want to access the properties used during the remote call (parameters to the call and/or AsycToken), you can make use of closures. Just define the result event handler inside the calling method as a closure. It can then access any variable in the calling function.
public function testSerivceCall(data:Object, callBackCommand:String):void
{
var _handleTestResult:Function = function( event:ResultEvent ) : void
{
// token is visible here now
if (callBackCommand == "FOO")
{
// do something related to "FOO"
}
else
{
// do something else with the result event
}
}
var remoteObject:RemoteObject;
remoteObject = new RemoteObject();
remoteObject.destination = "zend";
remoteObject.source = "MyService";
remoteObject.endpoint = "http://example.com/service";
remoteObject.test.addEventListener(ResultEvent.RESULT, _handleTestResult);
remoteObject.test.addEventListener(FaultEvent.FAULT, _handleTestFault);
var token = remoteObject.test(data);
}
If I'm reading your question correctly, you're trying to figure out how to access the actual data returned by the ResultEvent ?
If so, assuming you've made the call correctly and you've gotten data back in a format you're expecting:
private function _handleTestResult( event:ResultEvent ) : void
{
// you get the result from the result property on the event object
// edit: assuming the class Person exists with a property called name
// which has the value "John"
var person : Person = event.result as Person;
if (person.name == "John")
{
Alert.show("John: " + person.name);
}
else
{
Alert.show("Not John: " + person.name);
}
}
private function _handleTestFault( event:FaultEvent ) : void
{
// Maybe you know the type of the returned fault
var expectedFault : Object = event.fault as MyPredefinedType
if (expectedFault.myPredefinedTypesPredefinedMethod() == "BAR")
{
// something here
}
}
The ResultEvent has a property called result which will hold an instance of the object returned by the result (it might be the output of an XML file if using a web service, or a serialized object if using AMF, for example). This is what you want to access. Similarly, FaultEvent has a fault property that returns the fault information.
Edit: Changed code in _handleTestResult() in response to Gordon Potter's comment.