VS 2013
Blend
Windows Store App (8.1)
MVVMCross
I want to set the design time DataContext of a Page in my Windows Store (8.1) app. I am doing this using d:DataContext.
UPDATE
However this is being ignored at design time and I suspect this is an issue with MvvmCross
If I remove the "d:" it works but then it is not restricted to design time. If I try it on a standard Page rather than an MvxStorePage the d: is respected and the datacontext is set at Design Time only.
I originally thought that the d: was causing the DataContext setting to be ignored because when I removed the d: it worked. However I have just tried
d:DataContext="{d:DesignInstance Type=firsts:TipViewModel,
IsDesignTimeCreatable=True}"
and that works so it cannot be simply be the 'd:' but a combination of 'd:' and my approach of
d:DataContext="{Binding Source={StaticResource Factory},
Converter={StaticResource DesignConverter},
ConverterParameter=TipViewModel}"
I do not want to go direct to a DesignTime version of my VM instead I am using the approach in Nick's article Coded Design Time Data using Mvvmcross which lets me inject a DesignTime DataService into the exisiting VM
Has any got any ideas as to why my stuff is silently failing?
Thanks
Pat
Related
I'm trying to create a cross platform application using MVVMCross and portable class libraries, which interacts with an api and displays some data asynchronously.
Currently I am trying to generate a SHA512 hash value for a sign key that will be sent along to the api.
I am not exactly sure how I can implement the cryptology portion. I have tried using the SHA512 class, however it appears to be unavailable. I tried manually adding a reference to System.Security.Cryptology which didn't help.
I also tried additional packages on nuget such as SharpCrypt to see if they would help generate a hash value, however I see the error "the type or namespace name 'CryptSharp' could not be found" after adding the package from nuget.
I am targeting:
.Net Framework 4.5+
Windows Store apps
Silver light 5
Windows Phone 8
I'm quite a beginner so maybe I am missing something extremely obvious, any help or examples would be much appreciated.
Thanks!
I believe some of the crypto classes may also be available portably using the PCLContrib project - http://pclcontrib.codeplex.com - but I don't think this is yet available beyond Windows.
Where functionality isn't available portably, you can inject implementations into portable class libraries via an interface from each UI platform:
there's an example of this in the first part of N=31 in http://mvvmcross.blogspot.co.uk
there's a full introduction to MvvmCross dependency injection in https://github.com/MvvmCross/MvvmCross/wiki/Service-Location-and-Inversion-of-Control
I am trying to build a fairly simple sqlite database based mobile app using mvvmcross and Portable class libraries. The database I have running is fairly large so querying it takes enough time where I don't want the UI to get blocked while running queries.
The way I currently have it set up is in a few classes based on the mvvmcross n+1 tutorials n=10 tutorial. I have two services that manage the look-ups for the two entities.
How can I perform these database calls on a separate thread and have the view be updated when completed. I assume that this capability exists within mvvmcross I just haven't been able to track down the documentation or any tutorials on it specifically.
Any help pointing me to the right direction would be much appreciated.
Thanks,
JH
Portable class libraries do give you access to the ThreadPool - so you could use that to marshall the work onto a background thread? http://msdn.microsoft.com/en-us/library/system.threading.threadpool.queueuserworkitem.aspx
Alternatively, if you have a setup/configuration which allows the TPL to be used in your library, then you could use the TaskFactory or async and await to provide some background threading - this is probably the better long-term route, but getting this setup and working initially may take longer as Xamarin's async support is very new and it's PCL support is changing.
I've found a topic describing NullReferenceException in Windows Phone designer, however I believe this is a somewhat different issue, since it happens in all platforms and not related to MvvmCross plugins.
Designer (VS2012, Store/WP8/WPF apps) works fine for earlier versions of MvvmCross. I tried to compile a version that corresponds to 3.0.6 NuGet packages, and I can see that design-time model is loaded in all platforms.
Recent MvvmCross version causes all designer to raise NULL reference exception ("Object reference not set to an instance of an object") on all platforms.
Attempt to debug a VS instance didn't help: the call stack doesn't say much, and there is no MvvmCross code there.
The error is not related to the actual view/view model: I can remove all controls from the view, and the error is stil raised. The view model constructor code is never reached.
So it looks like there's some MvvmCross code (not from MvxView) that is unsuccessfully executed in at design-time. I wonder if this is a known issue and/or if there is a workaround to get designer work.
UPDATE. I created a GitHub issue with steps to reproduce the problem: https://github.com/slodge/MvvmCross/issues/347
This question moved to GitHub where there was lots of discussion and a few samples - https://github.com/slodge/MvvmCross/issues/347
From these samples, I believe we concluded the Nuget release 3.0.8.1 :
supports time data based on Blend-generated XML data files
supports design-time data based on simple C# classes
does not support design-time data where the data uses MvvmCross MvxViewModel as a base class
It isn't entirely obvious that developers should want to do the third thing (designtime data isn't real data?), but given that the overall MvvmCross manifesto broadly speaking aims to enable developers and to give them choice, then future MvvmCross will make this easier in the future.
In the meantime, if anyone wants to initialise objects at design-time, then there are a few helper classes around to enable this.
For example, the color plugin (and a small part of MvvmCross IoC) can be made available in the design-time environment using the MvxColorDesignTimeHelper - see:
https://github.com/slodge/MvvmCross/issues/323 (linked to MvvmCross throws NullReferenceException in Windows Phone Designer)
https://github.com/slodge/MvvmCross/blob/TibetBinding/Plugins/Cirrious/Color/Cirrious.MvvmCross.Plugins.Color.WindowsPhone/MvxColorDesignTimeHelper.cs
https://github.com/slodge/MvvmCross/blob/TibetBinding/CrossCore/Cirrious.CrossCore.WindowsPhone/Platform/MvxDesignTimeHelper.cs
I tried to analyze a swing application. It's an old project and it has been growing over years, so it's very hard to read the code. Now we should redesign the application.
Now I'm looking for an Eclipse plugin which could me support to understand this application. Here what kind of plugin I'm looking for:
start application from Eclipse in debug mode
I run in the application to a point
I start the record in Eclipse plugin
I run some kind of business logic in the application
I stop the record
the tool shows me, which code is used or not during the record
Does someone know if this kind of plugin exists?
Cheers
Julia
Not a specific plugin, but you can get something what you want by smartly placing breakpoints:
For example to find where the action listener code is for a button, set a break point in the ActionEvent constructor just before you press the button. Then you can step forward until you get to the listener.
You could also use VisualVM (or other profiler) to do CPU sampling while you take your action and then look in which code the CPU time was spent (in the EDT for the Swing GUI specifically).
It sounds like a coverage tool that can be switched on and off at runtime. I don't think this is possible with Emma or Cobertura; best guess is to use these for unit tests (or small test applications that only use partial functionality) and hide any unused types to get partial views. But that may not work well when you want to understand GUI actions and responses.
Even if it is not exactly part of your question I would recommend to have a look into the X-Ray plugin which helped me a lot with a legacy application.
Oh, and Eclipsecolorer Profiler helped... but the project is not active any more.
I am trying to write some simple Java web services so we can call Java code from .NET. So far, I got a proof-of-concept working under Glassfish. Pretty straightforward when the IDE does all the work.
Now I'm really bogging down on stuff in Java that should be really simple. For example, I want to externalize my configuration so I can change stuff like connection strings/usernames/application variables/etc without recompiling.
In .NET, you would just stick some strings in the web.config file in the root of the web site and use: ConfigurationManager.AppSettings["whateverIwant"];
I can get java.util.Properties to do what I want (from a standalone client), but I can't figure out where to put the .properties file and how to get the path to it from within the web service.
I need my approach to work within WebSphere Application Server as well. Thanks!
As others have mentioned, it greatly depends on the container, but almost always dynamic configurations are stored in a database instead of XML or .properties files.
As I see that this is just like a proof of concept, here's a quick and dirty solution: (don't do this for production code) use System Properties.
Disadvantage: with every change you need to reboot the container, but you don't need to recompile the app.
To use system properties in Glassfish you can go to the section "Configuration -> System Properties" and add properties there. Then from inside your application just call
String myValue = System.getProperty("myProperty");
To get the value. All java applications support these properties, but I don't know how to configure them in Websphere.
Alas, Java EE has a giant hole in the head when it comes to application configuration.
Your best bet is to either:
use JNDI to store config in the application server environment. This is hard to do portably, painful, and an absolute nightmare for the user to do any configuration. Configuration UI depends on which app server and version is in use and may be a command-line-only utility specific to that app server.
Use the Preferences API to store your configuration, and produce your own UI to edit it. This is OK ... except that you can't control when your settings are flushed and re-inited. Some app servers will do this when your app is re-deployed, which you probably don't want.
All in all, the situation absolutely stinks. There's no clean, sensible way for an app server to provide an app with a simple properties map and UI to edit it using the app server's admin tools.
I tried to work around this using web context parameters, but found that they too were buggy. Glassfish was ignoring more than the first web context parameter that was being set, and they were hard to access without having a servlet context so you couldn't really get to them easily across the whole app.
If anyone has a better answer I'd love to hear it, because the situation as it stands seems downright amazing for a spec that's been through several major iterations.
see also: Storing and editing configuration for Java EE applications
Application configuration is unfortunately container dependent. In general you access your configuration through JNDI. The approach I've recently used was the following:
Make a database available to your app (through JNDI, use the Glassfish database "wizard"). This is part is container dependent.
Create an entity bean that deserializes your settings from the database. The simple solution here is to have something like this:
#Entity
public class Setting {
#Id
private String name;
private String value;
...
}
Then it's a question of doing em.find(Setting.class, "whateveriwant").getValue(). Alternatively, you could create a single entity bean with all the settings as attributes.
Either way, this approach reduces the container dependency to a minimum.
The best solution I've found so far is "EAC4J (External Application Configuration For Java)". I've used successfully in many projects.
Put the following code in the contextInitialized method of a ServletContextListener:
ServletContext sc = sce.getServletContext();
Properties systemProps = System.getProperties();
String path = sc.getRealPath("WEB-INF/application.properties");
systemProps.load(new FileInputStream(path));
This reads from application.properties from the the WEB-INF folder of your web app when it starts. This will require a restart every time the configs change, but in my opinion, that is as it should be.