I'm new to Windows Universal app programming. Decided to use Tmeplate10 to create my first app.
I would like to know what is best practice to get Current Visual state name in View Model.
In code behind XAML I have been using:
VisualState vs = AdaptiveVisualStateGroup.CurrentState;
if (vs != null)
{
string actualStateName = vs.Name
}
What is best way to get same thing in ViewModel?
Please don't try to mess around with the visual state in your view-model. Consider this, your view-model exists to handle the underlying data necessary for your view. This is NOT the same thing as presenting the data in your view. Your view, on the other hand, has the logic to present data - and to do it with different visual states based on certain triggers. Those triggers are visual triggers, not data triggers. For that reason, you should handle visual states in the view and the implicit code-behind of the view.
If the data impacts the view, like if the user logs out suddenly or something, then that, too, is a property (like IsLoggedIn) in your view-model that your view uses to change the visual state. If you are trying to get a reference to the visual state in your view-model then you are sort of short circuiting the intent of MVVM.
That being said, I am not the developer of your app, you are. And, the code you are showing is the only way to reliably get the current visual state. It is worth pointing out that more than one visual state can be active at one time across multiple visual state groups. How could you possibly run the code you provided without a direct reference of the visual state group class in your view-mode? How to get it there?
Page.OnNavigatedTo() { ViewModel.Group = AdaptiveVisualStateGroup; } is how.
But I hope you consider the rest of the answer.
Related
I'm trying to edit a Master-Detail View multiple times in Catel.
My question is, if there is no common way in catel to handle a Master-Detail-View and multiple editions using the SaveViewModelAsync and CancelViewModelAsync methods?
The workflow works when my Master-ListItem is no UserControl with it's own ViewModel and when I change the selected Master-ListItem after save or cancel, so that a new ViewModel will be created. But I don't want to null or change the selection after a save/cancel. Also I have maybe to create a UserControl + ViewModel for the Master-ListItems.
Restrictions of the question:
I have got the information from Geert van Horrik from the discussion of his answer, that
multiple edit cycles are not supported directly
one Model should only be accesd by one ViewModel
Problem:
I can use the the SaveViewModelAsync and CancelViewModelAsync only once. After that, the ViewModels which are alive
will get no updates from the Model
don't create a BackUp from the Data, so that the changes can be reverted again
Code to Reproduce:
I have created a WPF Project, where I tested this all.
Possible solution:
I could use the EditableObjectHelper and handle this by myself
I have to instantiate the VewModel again, after the save or cancel, like it happends on a selection change in my Example Code
Restricion of the solution:
If I use a specialized UserControl for the ListItems of the Master-View, 2 ViewModels are looking on 1 Model. After the SaveViewModelAsync the ViewModel doesn't get any Notifications of the Model. So I would have to instantiate this ViewModel again too. But I would Breake the 1-1 relation of the ViewModel-Model.
My conclusion:
It seems, that I have to instantiate all these ViweModels and handle this workflow all by myself. It seems, that the ViewModelLifetimeManagement.PartlyManual (CloseViewModelOnUnloaded is Obsolete) doesn't work here. On selection change, always a new ViewModel will be created, the old one will probably just not be closed.
I don't want to misuse the framework. Maybe I have missed something. I hope somebody can help me or give me a tip, how to handle this.
Catel calls Save / Cancel as soon as the view model get's unloaded. If you want to do "intermediate" saves without changing the data model, you can:
Save the master list which will save the dirty models (you can directly modify the models from within your vm's)
Create a custom command (SaveData) that you can run from an explicit button (or input gesture binding) to save the data without calling SaveAsync on the vm
After the answer of Geert van Horrik, I currently ended up , don't using the SaveViewModelAsync and CancelViewModelAsync methods and handle the save and cancel by my own, so that the notification will not breake. I'm using the GetChildViewModels() method on the ViewModelBase and the EditableObjectHelper.CancelEditObject(Model);
i am beginner in Android Studio. I know there was a function called SharedPreferences, but i did not know how to use it.
Can anyone explain to me how to use it as i given the example above.
I didn't quite get what you said but here is as much as i know:
You first make a Sharedpreference Object and then a Sharedpreferemce editor object like this
Sharedpreference s=getApplicationContext().getSharedPreference("a name for your preference",and the mode that actually is zero 0);
Sharedpreference.Editor ed=s.Edit();
The rest is easy for editing values use ed.putboolean ,ed.putString ,ed.putInt and more and at last use ed.commit() or ed.Apply() to apply the changes you have made and for getting the values use s.getString
The concept is very easy Editor for editing and Sharedpreference for getting value
And at last when puting values the concept is like this
ed.putValue(key,value);
Key is the name and value is the value
And for getting keys the concept is like this
S.getValue(key,defvalue)
Key is the name of the variable that you saved value in it and the def value comes when that key is empty both are String types
And at last jf you are so new to android studio first learn basic things like lifecycle and much more it will help you alot.
Hope you get it
****EDITED**** but if you are talking about going to new activity from one activity that is not the Sharedpreference that is the Intent and startActivity by the way java hasn't got functions it has methods.
I am trying to activate a view using Revit API. What I want to do exactly is to prompt the user to select some walls, but when the user is asked that, he can't switch views to select more walls (everything is greyed out at that point).
So the view I want to activate (by that I mean, I want this view to be actually shown on screen) already exist, and I can access its Id.
I have seen threads about creating, browsing, filtering views, but nothing on activating it... It's a Floor Plan view.
So far I can access its associated ViewPlan object, and associated parameters (name, Id, ..).
Is it possible to do ?
Thanks a lot !
Arnaud.
I think the most preferred way is the UIDocument.RequestViewChange() method. The tricky part about this is that unless you've designed your application to be modeless with external events or idling, it may not actually happen until later when control returns back to Revit from your addin.
(There's also setting the UIDocument.ActiveView property - not positive if this has different constraints).
The other way that I have done it historically is through the use of the UIDocument.ShowElements() command. The trick here is that you don't have control of the exact view - but if you can figure out the elements that appear only in that view, you can generally make it happen (even if you have to do a separate query to get a bunch of elements that are only in the given floorplan view).
Good Luck!
I think the solution to your problem may be:
commandData.Application.ActiveUIDocument.ActiveView = View;
The ActiveView is a property and it has {get and set} options.
ActiveView has only a get accessor, what Mostafa suggests will not work.
I have used the RequestViewChange() method with a modal dialog and have not had problems so far.
I'm having trouble with the webparts variables... I came from standard ASP language, so, to me, store variables in session and other parts is the common way to do everything =)
Now i had to create a webpart, the wp has to write a graph from parameter and i cannot understand HOW variables works: i cannot understand WHEN saved and WHEN erased and other thing like this!
Let me explain: i have a web part with the configuration toolbar on the right in which i put the values.. Everytime a button is pressed or a value in the dropdown list changes, it raises an event which causes the "CreateChild" function..
Many times the data is "stored", other time they are not!
That's the way i used to store value (in the ApplyChanges override function):
WPChartGenerator wpParent = (WPChartGenerator)this.ParentToolPane.SelectedWebPart;
wpParent.WebUrl = txtWebUrl.Text.Trim();
And in the CreateChild event i get the value like:
WPChartGenerator wpParent = (WPChartGenerator)this.ParentToolPane.SelectedWebPart;
this.ddlWeb = new DropDownList();
this.ddlWeb.ID = "ddlweb" + wpParent.ID;
ddlWeb.SelectedValue = wpParent.WebService;
Now.. Sometimes this works, for example, when i push a button I invoke in the code of the button and then the code to store every value.. In some case (like buttons) this works, in other (like dropdown list index changed event) this fails and i found every object in the wpParent equal to it's initial value.
Another thing i noticed, is that in certain cases when an event is triggered, the first thing to be executed (even first than the event's associated code) il CreateChild (even first than OnLoad!!!)
Can anybody tell me what I'm doing in the wrong way? Do anybody has a good tutoria for this matter?
Thanks & sorry 4 my School level English =)
Forget to say that every variable has been implemented as a Property, like that:
[WebBrowsable(false)]
[Personalizable(PersonalizationScope.Shared)]
[WebPartStorage(Storage.Shared)]
public string WebUrl
{
get
{
return this.webUrl;
}
set
{
this.webUrl = value;
}
}
I can't see all the code there so I don't really know what you're doing wrong (i.e. do you actually have an ApplyChanges method) but from the way you've worded your question it sounds like you really need to start at the beginning, follow one of these walkthrough tutorials and make sure you understand the basics and then start adding in the code for your project.
MSDN - Creating Web Parts for SharePoint (VS2010)
MSDN - Walkthrough: Creating a Basic SharePoint Web Part (WSS 3.0)
Developing SharePoint 2007 Web Parts
I have an NSTableView which is populated via a CoreData-backed NSArrayController. Users are able to edit any field they choose within the NSTableView. When they select the rows that they have modified and press a button, the data is sent to a third-party webservice. Provided the webservice accepts the updated values, I want to commit those values to my persistent store. If, however, the webservice returns an error (or simply fails to return), I want the edited fields to revert to their original values.
To complicate matters, I have a number of other editable controls, backed by CoreData, which do not need to resort to this behaviour.
I believe the solution to this problem revolves around the creation of a secondary Managed Object context, which I would use only for values edited within that particular NSTableView. But I'm confused as to how the two MOC would interact with each other.
What's the best solution to this problem?
The easiest solution would be to implement Core Data's undo functionality. That way you make the changes to Core Data but if the server returns the error, you just rollback the changes. See the Core Data docs for details.