Localization of XAML, WPF applications.

As you may know, localization and globalization of user interfaces have been a topic I like to discuss. Being bilingual, I like to give the opportunity to applications to show their glory in several languages.

In my previous jobs, I have localized ASP.NET Web Forms and ASP.NET MVC forms, and also Windows Forms, but the other day someone asked me about WPF/XAML and MVVM. How to localize a XAML markup.

This is what this post is all about. Back in 2007, a coworker and I wrote a Localization Toolkit and published all the code Open Source at CodePlex, after writing an article about the new features in .NET 2.0 and Visual Studio 2005 that allowed you to generate resources files from the literal strings embedded on an ASP.NET web form.

Fast forward a few years to the end of 2007 and beginning of 2008, with the outcome of WPF, are resources files still in use?

Yup, they still are, and they are selected by the same mechanism that selects a given satellite assembly given the UI Thread Culture. The same mechanism that was available in the .NET world in 2005 for ASP.NET Web Forms.

Satellite assemblies are nothing but key/value pairs stored in a resource file that the ResourceManager type can search by Key.

Now, let’s say I generated resource file (.resx) for a given locale and region (fr-FR or fr-CA) and I want the resource file key bound to the XAML view after the UI Culture Thread is set to the OS locale and region, or after the user selects the locale and region he would like. Notice there are two settings to set with the locale and region: the UI Thread and the current thread. They are different.

            CultureInfo ci = new CultureInfo("fr-CA");
            Thread.CurrentThread.CurrentCulture = ci;
            Thread.CurrentThread.CurrentUICulture = ci;

 

How are the literal values bound to the proper resources file holding the locale and regional translation?

Within the Window tag of your XAML window file, add the following line of code:

xmlns:properties="clr-namespace:YourAssemblyName.Properties"

For each control within our grid (Button, Labels and Window Title) do not set the Title or Content values to static text. Instead use the resources file value.

<Label Content="{x:Static properties:Resources.LabelFirstName}"…/>
<Button Content="{x:Static properties:Resources.ButtonSubmit}"…/>

There are also other projects at GitHub that have been added recently specifically for WPF: WPFSharp.Globalizer which offers a better option than the LocBalm tool to generate and  maintain the resources files for translation.

LocBaml is the de-facto tool documented on MSDN for WPF resource generation, but there are other projects such as the one mentioned above and the NuGet package ResXManager that offers more features.

LocBalm will generate UiDs on your XAML markup that will link automatically to the regional resource after the Current UI Thread is set. LocBalm can also be used to generate the different resource files after the application is developed, using the option to parse the main assembly for XAML markup.

Parlez vous Français? Oui, mais mon interface ne parler pas.

Should I use sessionID to uniquely identify users?

Should I use sessionID to uniquely identify users?
NO, that’s why UserId/UserName or LoginID and password combinations are for.
SessionID is a “random” string and can be repeated (e.g. when IIS is restarted or the server is rebooted, the sequencing scheme that generates SessionID values is reset). So if you store information for a user based on the SessionID value, be very aware that a new person next week might happen to get the same SessionID value–this will either violate a primary key constraint, or mix two or more people’s data.

However in ASP.NET, the SessionID is 120 bits in length, so like a GUID, is virtually guaranteed to never repeat.

But in classic ASP, this built-in mechanism is not a good strategy for identifying users over the long term. A better methodology would be to generate a key value in a database that is guaranteed to be unique (e.g. IDENTITY or AUTOINCREMENT) and store that in a cookie on the client. Then you can identify them not only for the life of their current session, but during future visits as well (of course, only until the next time they delete their cookies).

As usual, it depends, on the technology you inherit, how the old modules were built and so on.

Storing ASP.NET SessionId and at the same time storing a SessionGUID generated from the SessionId in ASP.NET doesn’t make much sense.

L.

Selling my book collection at Amazon…

I recently moved to a smaller place and can’t keep all my technical book collection.

I’m selling the books that I already read, no longer need or have duplicates. Some of them are for old .NET frameworks, but if you are maintaining legacy applications with these framework versions, the books from Microsoft Press can be helpful.

There are also books about SOA and SOAP, SQL Server specific books etc. The books are selling pretty fast.

You can access my seller’s collection at Amazon here.

All the prices are set for shipping within the USA only.

Happy coding!

Closures in the Task Parallel Library, what are they? …beware of race conditions.

Up to .NET 3.5 multi-threading programming had it challenges. Multi-threading is a way to improve application performance and responsiveness by running long operations in a different thread from the main application thread.
Up to .NET 3.5 the parallel threads created by an application domain only targeted a single CPU core by CPU affinity. We also know that CPUs (Central Processing Units) couldn’t increase the processor clock without melting the integrated circuits away and requiring bigger cooling fans. So, the hardware evolved into placing several CPU cores in parallel to increase computing power.
The task parallel library introduced in .NET 4.0 responded to the need of catching up with the hardware capabilities and as a way to execute parallel operations in different cores.
Each task created by the TPL has its own stack and a thread or set of CPU threads.

When creating a task, a common code snipped to launch a task using a Lambda expression as an Action is:

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Task.Factory.StartNew( () =>
   {
       statement1;
       statement2;
   }
);

However, very rarely a newly created task will receive no data from the method invoking it.
It is more likely to have the following code inside a C# method calling a parallel task:

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...
int y=45;
 
Task.Factory.StartNew( () =>
    {
        y++;
    }
);
...

y is a variable that is passed to the parallel task for further processing.
Now, what would be the value of the variable y when the task finishes running?
Is y passed by value or by reference?

After the task completes the value of the primitive y is 46. y is indeed passed by reference. These variables passed to a task receive the name of closures.

Now, from multi-threading programming you might remember that objects that were shared between several threads could end up with a value that was not predictable, this was the dreaded race condition. There were ways to mitigate this condition such as using the lock statement to avoid concurrent threads affect the state of the object in an unpredictable way. Threads compete for CPU time and there is no guarantee that they will execute sequentially or in a predictable order.

You can also cause race conditions with closures in the task parallel library. Let’s see how:

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...
int y=45;</code>
 
Task.Factory.StartNew( () =>
    {
       y++;
    }
);
...
Console.WriteLine(y);

In the example above, y won’t always be 46.

Once the task is kicked off, it is set in queue for processor time, and so is the main thread where the method that starts the task is.

They both compete in parallel for CPU cycles and run as parallel as possible. The executing code gets forked. If the main thread runs first while the parallel task is waiting in queue, the value of y will be displayed on the console as 45. If the task runs before the main thread makes it to the Console.WriteLine statement, the displayed value will be 46.
This is a typical race condition.

You have several ways to mitigate this condition in the TPL. One of them is shown below:

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int y=45;
Task t = null;
    t = Task.Factory.StartNew( () =>
       {
                y++;
       }
);
Task.WaitAll(t);
Console.WriteLine(y);

The example above will always show 46 in the console.

Determining the .NET target version of a dll or .exe assembly

It’s been a while since I blogged. It’s good to be back.

I switched job descriptions and became an application architect, which means, I get to decide how solutions are designed…and if the solutions won’t work, the blame goes on me :-p

Now seriously, I was reviewing old posts and realized WordPress didn’t make a good job at keeping my old code snippets from Blogger :(, the formatting is way off and you can hardly see the code properly. Oh well.

Today we had a deployment issue, one of our projects was compiled to the wrong target framework. When we compared properties and sizes we realized this was not the ordinary dll size, but how could we determine the actual target framework?

The windows explorer properties or the IIS properties are of no use in this case, giving you only the build number.

There are actually two main options with two utilities distributed on the SDK to determine the target framework of a dll or exe:

  1. ILDASM.exe
  2. CorFlags.exe
ILDASM.exe to determine framework version
ILDASM.exe to determine framework version

and if you want to use CorFlags.exe:

CorFlags.exe determining target framework version of a dll

Happy coding 🙂

L.

IIS 6.0 does not serve aspx pages out of the box

I have used ASP.NET for quite some time. I have probably always been lucky that the infrastructure or deployment person always enabled aspx on IIS for me. I use a Windows XP with IIS 5 sometimes or Vista with IIS 7. They do serve aspx pages by default, on XP once the .NET framework is downloaded and installed, there is nothing else to tweak.

On Friday afternoon, I had to deploy to an IIS 6 box on windows 2003, to my surprise, it didn’t serve any of the aspx pages. Even a small Hello World project on an simple label. I missed the happy hour with my colleagues and went home completely puzzle. Why? ASP.NET was already available when Windows 2003 saw the light. To my surprise there was nothing on the event log.

The answer came a few hours later and after few Google queries:

IIS 6.0: ASP.NET Is Not Automatically Installed on Windows Server 2003

1. Open IIS Manager, expand the master server node (that is, the Servername node), and then select the Web service extensions node.
2. In the right pane of IIS Manager, right-click the extension that you want to enable. In this example, this is Active Server Pages.
3. Click to select the Allow check box.
Add a New Web Service Extension to IIS 6.0

To permit IIS to serve content that requires a specific ISAPI or CGI extension that is not already listed in the Web service extensions list, follow these steps:
1.Open IIS Manager, expand the master server node, and then select the Web service extensions node.
2.In the right pane of the IIS Manager, click Add a new Web service extension under Tasks.
3.In the Extension name box, type a friendly name for the extension that you want to add (for example, FrontPage Server Extensions).
4.In the Required files box, click Add, and then select the path and the name of the file that will handle requests for the specific extension. After you select the path and the file name, click OK.
5. If the extension must be enabled immediately, click to select the Set extension status to allowed check box.
6. Click OK to save your changes.

Hopefully Mono will run seamless  on Apache one of these days…

Identifying performance bottlenecks on a .NET windows app. Part II Using Native Images with CAB, reviewing Fusion Logs

We left off on the previous post with a newer version of NHibernate and a different mapping that avoided the byte per byte comparison of our byte arrays, however our application start up was slower, about 20 seconds and showing some screens for the first time was taking 10 seconds, not acceptable.

The performance decrease was gone but the start up was not good enough.

We got our hands on ANTS profiler again to see what was going on whenever we invoked a screen for the first time:

CPU usage:

Jitted Bytes per second:

and IO Bytes Read:

From these images we deducted there was quiet some Just-In-Time compilation going on when the screen was loaded. How to solve that? Using Native Images for our assemblies in order to avoid JIT compilation, see this MSDN article for this.

All in all that was quite easy to narrow down, we used NGen, installed the native images and voila!, let’s profile again…

I wish it were that quick, we kept seeing JIT peaks :-O

Alright, let’s use some heavier artillery and see why it’s still JITting.

This is where we got our hands on Fusion logs. Fusion is the engine (DLL) in charge of loading and binding assemblies. The Fusion Log Viewer is the tool to see the logs for this DLL and troubleshoot loading problems. This tool is part of the SDK and can be downloaded from here. We aware that it’s a heavy download. In order to use this tool once the SDK is installed:

1. Open in Fuslogvw.exe in folder C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Bin
2. If it shows up any entry click on the list box click on Delete All.
3. Click on Settings and choose Log all binds to disk and check Enable custom log path
4. And in the Custom log path edit box type C:\FusionLog
5. In C: drive create a new folder and name it FusionLog
6. Now run the application and execute scenarios where we are seeing JIT-ing
7. Now when you browse to C:\FusionLog you would see couple of folders.

We were unable to install the SDK in our production clients, so we ended up doing a registry edit in order to collect the logs. If you don’t want to install the SDK, do the following:

1) Go to regedit
2) HKEY_LOCAL_MACHINE\Software\Microsoft\Fusion
3) Click on the right pane and new -> string value
4) Name it LogPath,click it in the value write C:\MyLog
5) Again right click the right pane
6) go for new DWord value,name it ForceLog
7) click it and give Value “1”
8) Then create a folder in C drive with the name MyLogs
9) Run the app and logs will be created

The logs are created as HTM files in the folder you decide. reviewing our logs we found out one of our main modules wasn’t loading from its native image although the native image was on the native image cache. Why?

Let’s give some more background information, we use CAB.

The Composite UI Block from Patterns and Practices had a main release on December 2005, there’s been other releases for WPF and the most recent Prism project, but apart from the Smart Client Factory addition, the CAB framework has stayed pretty much the same for Windows Forms.

CAB is known for its Module Loader Service and was highly welcomed by windows developers as a framework that allows loose coupling with it’s Event Publishing/Subscription mechanism, it’s Services module and its MVP implementation.

All that is very good for the developer and for maintainability but the performance is not the greatest if you have quite a few publications and subscriptions going on and if you have a few modules loaded at start up. There are quite a few posts regarding this on CodePlex’s CAB forum.

I could go on and on about the beauty of CAB and despite its performance issues, I do believe it offers more advantages than disadvantages to the windows developer. IMHO, being able to give modules to develop to different teams and being able to plug them into the application without any major compilations, only a configuration change is a big big plus, see these posts on CAB Module Loader Service (CAB Modules on Demand) and Dynamically Loading Modules in CAB)

The main reason for this module not loading from its native image is due to the Reflection mechanism currently used in CAB’s Module Loader Service:
(namespace Microsoft.Practices.CompositeUI.Services)
assembly = Assembly.LoadFrom(file.FullName);

More information on Cook’s archives

Codeplex community member Mariano Converti was prompt on offering a solution on his blog.
How To: Use the Ngen tool to improve the performance in CAB / SCSF applications

As to the date of this post, this code change hasn’t been incorporated into any CAB release, they should do it soon though.

Happy performance troubleshooting!

Identifying performance bottlenecks on a .NET windows app using Windows Debugging Tools and ANTS Profiler. Part I: NHibernate byte[] types

This is a curious case that led me to discover and use a very valuable tool ANTS Profiler and read a few good blogs about .NET debugging and CLR internals. Read on to bookmark with me.

Near to Christmas we received a complain one of the windows applications was performing too slow after a few hours of usage. Performance monitor counters indicated the performance problem lied on high CPU peaks sustained for a long period of time.

.Net memory counters were somewhat fine, no increase on allocated bytes or overall memory consumption, no high IO reads, no high network usage…apparently the application was just doing its stuff, but for a long time, and each time longer…

First thing that came to our mind was an infinite loop, however the curious part on this case is that the CPU peaks took longer the longer the end user worked on the application and began to be noticeable after a couple of hours, not quite the definition of an infinite loop.

If only had we had a better CPU, had the performance downgrade been noticeable after more hours. This is something we had to be thankful for, bad CPU, less time to reproduce the problem. This was one of the typical production only problems too :-p

Long sustained CPU peaks, how we dug down on the cause:

First we grabbed the free debugging tools (insert the obvious reasons here, budget, management approval, etc): CLRProfiler, winDGB, SOS and ADPlus.

Two great blog posts about how to start with these tools can be found here (Speaking Of Which) and here (Maoni’s blog).

MSDN Magazine also has two good articles (Bugslayer column and this CLR Inside Out column) on the subject of windows debugging tools and how to use them in VS 2005.

Back to our own experience on the matter, CLRProfiler hung the machine beyond response and despite being able to sketch the object graph in memory, it was hard to correlate the time of the high CPU peaks with the information obtained from CLRProfiler.

This was not due to a problem with the tool itself, hanging was due to poor iron power and our over-consuming application and the inability to detect the main CPU usage cause was due to the fact that CLR profiler is only meant to identify and isolate problems related with garbage collection, excessive long lived objects or huge collections.

At first we thought the high CPU could be related with garbage collection due to long lived objects, see this post on Tess’s blog If broken it is, fix it you should.

We collected memory dumps with ADPlus during the high CPU peaks as per this lab blog post and analyzed the memory dumps using WinDBG.

At the end we decided to have more control on when the dumps were taken and use WinDBG while attaching it to the process. I should also mentioned ADPlus ended up generating dumps with errors when the system was really stressed.

Instructions to take dump via WinDBG :
1. Run the application.
2. Open up WinDBG. Click on File ?> Attach To Process ?> Select the process ?> Click on OK.
3. WinDBG attaches to the process and waits on the command line. Press ‘g’ and hit enter. ‘g’ is for letting the
application run.
4. Now whenever you want to take a dump, Hit Ctrl+Break in WinDBG. Now, type : .dump /ma C:\Dump1.dmp
This will take a dump.
5. Press ‘g’ and hit enter for the process to resume.

WinDBG can give valuable information about the CLR stack at the time the dump was collected (clrstack command), the types being scheduled for GC (!finalizequeue) and how many types marked for finalization belong to Gen 0, Gen 1 and Gen2.

Seeing your managed stack at a single point in time or having exact information about the memory allocation does not give information on the amount/% of CPU time each method takes though.

We tried taking dumps with WinDbg at the beginning of the CPU peak, in the middle and at the end but the results only offered a hint, too many Collections were allocated and lived to Gen 2. Some of this collections were byte arrays. It wasn’t apparent from analyzing the three managed stacks (from the three memory dumps) which method was consuming the longest time.

So far we had lots of collections surviving to Generation 2 and some of them were of type byte array. Garbage collection counters, however were within the “normal”.

If the application was just “busy” doing its stuff, where was this time spent? Data Binding? Event Brokerage? Database access latency and query performance had been already discarded with SQL Profiler btw.

The main sustained CPU peak cause was discovered using ANTS profiler. Memory leaks, long GC cycles were discarded using the mentioned free tools.

ANTS profiler will let you set .NET performance counters and it will attach itself to the application being debugged. You cannot set breakpoints, afaik, but can go back in the profiler results and drag your cursor over a region to get a full called stack walk. It also goes beyond that and will indicate the % of time each method is taking on CPU and the % of time its children take on CPU usage.

Finally! A tool that will correlate performance counters the called stack for you and will indicate % of CPU time per method. This information you cannot gather by taking memory snapshots or called stack snapshots, unfortunately the free tools were only useful to discard memory leaks and GC related problems on this particular case. They narrowed down the places to look into.

As you can see from the ANTS Profiler screen shot the application was indeed doing stuff, in this case comparing collections of bytes, byte per byte…Ouch!

We were able to identify the Collection comparison problem (byte[] arrays were being compared when the
NHibernate session was flushed and persisted even when they didn’t changed). We correlated this with a
fixed NHibernate bug:
http://jira.nhibernate.org/browse/NH-1246
and changed our mapping attributes to indicate there was no need to update the BinaryBlob fields. Our application either inserts the binary data or deletes its.

Note: you should be logged into http://jira.nhibernate.org/ before navigating to this bug report, registration is free.

Our NHibernate version and mapping strategy contained the buggy bits…

I hope this post hasn’t turned out too long, by upgrading NHibernate we solved the mystery of performance downgrade over time, the more the user worked with persistent binary data in the application the longer this loop comparing byte per byte on each collection took.

Upgrading NHibernate added to a performance challenge in another area, the application start up was taking longer. This will go on Part II as I should get some sleep.

Sweet dreams!

PS. VSTS 2008 has very promising capabilities for debugging high CPU usages, almost as good as ANTS Profiler, see this post

If you call your .NET application from a batch file…

If you deploy your .NET applications with a batch file, be aware that the way you call your .NET application might affect how it behaves.

The facts are as follows (for our application anyways):

when the application is called using the following line in the batch file:

start C:\Progra~1\ApplicationFolder\Application.exe

the application fails

if you call the application using the windows explorer in the batch file:

explorer C:\Program Files\ApplicationFolder\Application.exe

it works fine but it shows a security warnings that you’re downloading files and that publisher is unknown…Not good for the end user, not good.

If you call the application from a path that doesn’t have white spaces using the start command, it works fine:

start C:\ApplicationFolder\Application.exe

(This option would be good if we didn’t use Program Files for the deployment, but most people do)

and, finally, if you use the start command but take out the DOS path it works!

start ” ” “c:\Program Files\ApplicationFolder\Application.exe”

I checked the assemblies binding errors, the code access security for every assembly in the application, debugged the application, et-cetera without results.

Changing the old DOS path did the trick!!!

Why? I still have to get a hold on this script guy to ask him why :-p

Happy coding!

how to determine the assembly evidence at runtime

I ran into a problem the other day, one of the .NET applications we had deployed started crashing on some screens for no apparent reason. The application worked fine in the development environment and when called from the C drive in the test machine.
We tested for binding problems using the SDK tool fuslogvw.exe, but didn’t see any binding errors. The other SDK tool we tried was the .NET Framework configuration tool MScorcfg.msc, no luck. As the SDK doesn’t ship with the Framework 2.0 we had a trouble to do these tests on every single production machine…let alone that the Configuration tool does not show run-time evidence for a given assembly.
Maybe the enterprise policy had changed for the different zones and this .msi had been pushed without us knowing…
The MScorcfg.msc said otherwise…

This code and extra logs in our application did the trick on determining the evidence passed to the CLR:

private static void LogEvidence()
{

Zone myZone;
Url myURL;
Hash myHash;
Site mySite;

String strEvidence = “”;

log(” ===================== Assembly Evidence: ========================= “);

foreach (Object myEvidence in System.Reflection.Assembly.GetExecutingAssembly().Evidence)
{
strEvidence = myEvidence.GetType().ToString();

switch (myEvidence.GetType().ToString())
{
case “System.Security.Policy.Zone”:
myZone = (Zone)myEvidence;
strEvidence = strEvidence + “: ” + myZone.SecurityZone.ToString();
break;
case “System.Security.Policy.Url”:
myURL = (Url)myEvidence;
strEvidence = strEvidence + “: ” + myURL.Value;
break;
case “System.Security.Policy.Hash”:
myHash = (Hash)myEvidence;
strEvidence = strEvidence + “: ” + BitConverter.ToString(myHash.SHA1);
break;
case “System.Security.Policy.Site”:
mySite = (Site)myEvidence;
strEvidence = strEvidence + “: ” + mySite.Name;
break;
default:
break;
}

log(strEvidence);

}
log(” ===================== End of Assembly Evidence: ==================== “);

}