I'm trying to use telerik:PersistenceManager.StorageId property on RadGridView to persist the component status in the local storage.
If I set the property like this:
telerik:PersistenceManager.StorageId="rgvItems"
all works fine but I would like to set the StorageId dynamically using binding.
To do that, I've tried to set the property like this:
telerik:PersistenceManager.StorageId="{Binding Path=StorageId}"
where StorageId is a DependecyProperty defined in the component xaml.cs file:
public string StorageId
{
get
{
return (string) GetValue(StorageIdProperty);
}
set
{
SetValue(StorageIdProperty, value);
}
}
public static readonly DependencyProperty StorageIdProperty =
DependencyProperty.Register("StorageId", typeof(string), typeof(vGridContainer));
and set in the component constructor like this:
public vGridContainer(string storageId)
{
InitializeComponent();
DataContext = this;
StorageId = ConfigurationManager.AppSettings["PersistenceManager.StorageId"]
[...]
}
With that code the grid view status is not persisted.
Am I missing something?
Thank you all in advance :)
I've tried everything about binding property from xaml but nothing worked.
Finally I solved that issues setting the attached dependency property from code like this:
rgvCheckIn.SetValue(Telerik.Windows.Persistence.PersistenceManager.StorageIdProperty, ConfigurationManager.AppSettings["PersistenceManager.StorageId"]);
Now it works fine.
Hope that helps anyone that is experiencing the same issue :)
Related
can someone please explain me the code written below
public IList<GetProductPrice> CurrentPage
{
get { return ViewState["CurrentPage"] as List<GetProductPrice>; }
set { ViewState["CurrentPage"] = value; }
}
It is called a Property. They generate a getter and setter functions when compiled:
List<GetProductPrice> GetCurrentPage(){
return ViewState["CurrentPage"] as List<GetProductPrice>;
}
void SetCurrentPage(List<GetProductPrice> value) {
ViewState["CurrentPage"] = value;
}
//i think its actual get_.. but it doesn't matter for the example
So its generates ease of use getter setters. which you can just call by using:
var test = CurrentPage; //compiled to var test = GetCurrenctPage();
CurrentPage = test; //compiled to SetCurrentPage(test);
If you leave the getter and setter empty like this:
public int CurrentPage
{
get;
set;
}
it will also generate a backing field on the class where it stores the data:
private int _currentPage;
public GetCurrentPage(){ return _currentPage }
public SetCurrentPage(int value) { _currentPage = value }
Why do we do this?
Using getters and setters is a very old best practise from java (where ide's would have an option to generate them). But this would lead to a lot of boilerplate code!
In C# they try to counter this by adding these properties. But why do we need getters and setters? For example if you want to be notified when a value changes (to mark the classes it self as dirty). I think entity framework uses it to track if a model is changed otherwise it wont do a db update call. There are also other usefull tools that inject code in properties on compile time. to add extra functionality.
How not to use it:
using properties to return HttpContext.Current Is a dangerous one because you secretly depend on the HttpContext so try not to do this at any time!
Generally its also bad practise to use it when the code inside the get or set is very heavy (very instensive). Its bad practise because someone else using the code might think he is just setting a property/field while actually some very heavy code is executed. its best practice to make a special function for this instead and private the getter/setter:
public int Property {get; private set; }
public SetProperty(int value){
//intensive code here:
Property = value;
}
This property is letting the consumer of the property to use it like Local collection without referring the ViewState in the code. It will make the code simple and easy to use.
get { return ViewState["CurrentPage"] as List<GetProductPrice>; }
Here the ViewState object ViewState["CurrentPage"] is converted to list of GetProductPrice
set { ViewState["CurrentPage"] = value; }
Here the List is assigned to ViewState["CurrentPage"]
This code will only work in a controller, where ViewState is a property. This CurrentPage property provides a statically-typed way to access a certain ViewState item through that property.
So instead of sprinkling ViewState["CurrentPage"] as List<GetProductPrice> all over your controller code where you want to access the "current page", you can now simply use the CurrentPage property.
Of course "current page" is a term made up by the developer who chose to name things like this, I don't see how a List<GetProductPrice> has a relation to the "current page".
My goal is to set the properties of custom controls from a Page using xaml. I'm attempting to create a custom set of menu items, that all look the same but each one contains a different title. How could I set the title of each menu item from Xaml?
For Example sake, Ive simplified my actual code from the project to something simple.
What I want to do is something like this:
<local:CustomControl someCustomAccessor="some text">
While setting the property for the custom control like this:
class CustomControl: ContentView{
private string someText { get; set; }
public static BindableProperty TitleProperty = BindableProperty.CreateAttached("someCustomAccessor", typeof(string), typeof(CustomControl), null, BindingMode.TwoWay);
public CustomControl()
{
Content = new Label
{
Text = someText
};
}
private string someCustomAccessor
{
get { return someText; }
set { someText = value; }
}
}
I've looked everywhere for something like this and have come up short. Please help.
It's been a while since I've done something similar to this, but drawing on my Silverlight experience...
The .CreateAttached("someCustomAccessor" ....
Tells the binding engine to look for a Public property called someCustomAccessor, yours is currently private and will need to be Public. Also change the casing to be SomeCustomAccessor.
Also, the Binder doesn't know that it's a string, so it will need to be cast and set appropriately in the get;set;
public string SomeCustomAccessor
{
get { (string)GetValue(TitleProperty); }
set { SetValue(TitleProperty, value); }
}
Also the binding in your example is TwoWay, it may only need to be OneWay, but you can change that once you've got it working.
I have a problem when I try to bind the "Enabled" property of my Android Button to a Boolean of my ViewModel using the MvvmCross framework and I really don't know the origin of it.
So I have a ViewModel which contains the two following properties :
private ProjectDetailDTO _projectDetail;
public ProjectDetailDTO ProjectDetail
{
get { return this._projectDetail; }
set
{
_projectDetail = value;
RaisePropertyChanged(() => ProjectDetail);
RaisePropertyChanged(() => HasPicture);
}
}
private bool _hasPicture;
public bool HasPicture
{
get { return ((this.ProjectDetail != null) && !String.IsNullOrEmpty(this.ProjectDetail.Pictures)); }
set { _hasPicture = value;
RaisePropertyChanged(() => HasPicture);
}
}
As you would understand, my button is bind to the HasPicture property. So I have the following code for my button in my .axml file :
<Button
local:MvxLang="Text LblSeePicturesValue"
local:MvxBind="Enabled HasPicture,Click ShowProjectPicturesCommand"
android:id="#+id/buttonPictures"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true" />
I don't think it's a ViewModel problem because my WP application works well with this code. In fact, my ProjectDetailDTO is filled by calling a web service, so by an asynchronous method. I think it's why when the binding is realized the HasPicture property has the false value. But with my ViewModel code, the HasPicture property should be updated when the ProjectDetailDTO is filled. Is there anything I did wrong in my Android View?
Thanks for any help !
I think what you are seeing here is some interaction between ICommand.CanExecute and the Enabled property. There's a discussion about this on https://github.com/MvvmCross/MvvmCross/issues/729
To work around this, try switching the binding to:
local:MvxBind="Click ShowProjectPicturesCommand;Enabled HasPicture"
(Also note that the separator in bindings is a ; - not a ,)
I'm working on a ASP.NET WebApi (Release Candidate) project where I'm consuming several DTOs that are marked with the [Serializable] attribute. These DTOs are outside of my control so I'm not able to modify them in any way. When I return any of these from a get method the resulting JSON contains a bunch of k__BackingFields like this:
<Name>k__BackingField=Bobby
<DateCreated>k__BackingField=2012-06-19T12:35:18.6762652-05:00
Based on the searching I've done this seems like a problem with JSON.NET's IgnoreSerializableAttribute setting and to resolve my issue I just need to set it globally as the article suggests. How do I change this setting globally in a ASP.NET Web api project?
I found easy way to get rid of k__BackingField in the names.
This fragment should be somewhere in the Application_Start() in Global.asax.cs:
JsonSerializerSettings jSettings = new Newtonsoft.Json.JsonSerializerSettings();
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings = jSettings;
Looks like the default setting takes care of it.
Since the library does not expose a static setter for the DefaultContractResolver, I suggest you create a static wrapper over JsonConvert and it's Serialize*/Deserialize* methods (at least the ones you use).
In your static wrapper you can define a static contract resolver:
private static readonly DefaultContractResolver Resolver = new DefaultContractResolver
{
IgnoreSerializableAttribute = true
};
This you can pass to each serialization method in the JsonSerializerSettings, inside your wrapper.
Then you call your class throughout your project.
The alternative would be to get the JSON.NET source code and adjust it yourself to use that attribute by default.
For me, the following fixed the issue with circular references and k__BackingField.
In your WebApiConfig add the following to the Register() method:
JsonSerializerSettings jSettings = new Newtonsoft.Json.JsonSerializerSettings {
ContractResolver = new DefaultContractResolver {
IgnoreSerializableAttribute = true
},
ReferenceLoopHandling = ReferenceLoopHandling.Ignore
};
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings = jSettings;
Friends, don't declare properties like this:
public String DiscretionCode { get; set; }
But, create auxiliar vars, like old....
private String discretionCode;
public String DiscretionCode
{
get { return discretionCode;}
set { discretionCode = value; }
}
In Flex (Flash Builder 4), I need a way to know if something in an array collection has changed.
I have a custom object:
[Bindable]
public var _myobject:MyObject;
It's basically just a class containing a bunch of different String and Number properties.
I need a reliable way to know if any of the properties have been changed. For example, I am binding the properties to a user interface (fields), but it's also possible for some of the properties to change through code.
Is there a way to do this? I found ChangeWatcher, but that looks like it only looks at a single simple property, such as a String or Number. I need to watch or detect changes in all the properties in my object, hopefully without having to add ChangeWatcher events to every property. Is this possible?
You're probably better off just dispatching binding events on the specific properties you want bindable. Better yet, dispatch a custom binding event, so that all of the things that are bound don't have to filter for "is this the property I care about?" It's really easy with Flash Builder 4.5 to do this, just select your variable name and press Ctrl-1, select "Create getter and setter," select getter and setter and check "Bindable" and "create custom event."
This will create code for you that looks something like this:
private var _yourProperty:String;
[Bindable (event='yourPropertyChange')]
public function get yourProperty():String {
return _yourProperty;
}
public function set yourProperty(value:String):void {
if (value !=== _yourProperty) {
_yourProperty = value;
dispatchEvent(new Event('yourPropertyChange'));
}
}
This will be much less verbose and more performant than the code that Flash Builder generates for you behind the scenes when you just use the Bindable tag on its own.
If you use defined classes as VO/DAO and apply the [Bindable] tag to the class, this will do binding on all properties for you (so long as they are read/write).
Anonymous object detection is difficult at best, let alone adding additional headaches of loosing compiler type checking.
Super basic example: - the key is to tie it to the dispatcher, so internally it can send out the PropertyChangeEvent.
[Bindable]
public class Actor extends EventDispatcher
{
public var fName:String;
public var lName:String;
public var age:uint;
public function get displayName():String
{
return lName +', '+ fName;
}
public function Actor()
{
super();
}
}
public class BindableDictionary extends EventDispatcher {
public function BindableDictionary() {
super();
}
public var dictionary:Dictionary = new Dictionary();
[Bindable("change")]
public function get(key:Object):Object {
return dictionary[key];
}
public function put(key:Object, value:Object):void {
dictionary[key] = value;
dispatchEvent(new Event(Event.CHANGE));
}
}
maybe this class will give you some new idea