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  • How do I configure namecheap for "arbitrarily-nested" wildcard subdomains?

    - by rabidsnail
    I'm trying to set up something like nyud.net, where any arbitrary chain of subdomains resolves to the same CNAME record (which in my case points to an amazon elastic load balancer). Ex: www.gogle.com.nyud.net:8080 points to one of their cache servers, which looks at the HOST header and returns www.google.com. I'm using namecheap as my dns host. Adding a CNAME record for *.mydomain.com doesn't seem to do anything (nslookup gives NXDOMAIN for all subdomains). What do I have to do to set this up? Do I have to use something fancier than namecheap (like route53)?

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  • If I create a transient property in the model, isn't this managed by core data then?

    - by mystify
    Just to grok this: If I had a transient property, lets say averagePrice, and I mark that as "transient" in the data modeler: This will not be persistet, and no column will be created in SQLite for that? And: If I make my own NSManagedObject subclass with an averagePrice property, does it make any sense to model that property in the xcdatamodel file? Would it make a difference if I would simply create a property in my subclass and not model that in the entity? (I think: yes, it doesn't matter at all ... but not sure)

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  • JPA: what is the proper pattern for iterating over large result sets?

    - by Caffeine Coma
    Let's say I have a table with millions of rows. Using JPA, what's the proper way to iterate over a query against that table, such that I don't have all an in-memory List with millions of objects? I suspect that the following will blow up if the table is large: List<Model> models = entityManager().createQuery("from Model m", Model.class).getResultList(); for (Model model : models) { // do something with model } Is pagination (looping and manually updating setFirstResult()/setMaxResult()) really the best solution?

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  • Drupal CCK Date: how to set datetime field's default value to a fix date?

    - by Daj pan spokój
    Hi, I have a CCK datetime field and would like to set its default value to 31 May 2011. When I go to the configuration of the field I can set the default value to Now, Blank or Relative. Relative is to be set by a PHP's strtotime argument. However, it fails when I set it to 31 May 2011 last day of May 2011 (that should normally work according to http://php.net/manual/en/function.strtotime.php) Do You have any idea how to set it to default to 31 May 2011?

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  • Passing ViewModel for backbone.js from MVC3 Server-Side

    - by Roman
    In ASP.NET MVC there is Model, View and Controller. MODEL represents entities which are stored in database and essentially is all the data used in a application (for example, generated by EntityFramework, "DB First" approach). Not all data from model you want to show in the view (for example, hashs of passwords). So you create VIEW MODEL, each for every strongly-typed-razor-view you have in application. Like this: using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace MyProject.ViewModels.SomeController.SomeAction { public class ViewModel { public ViewModel() { Entities1 = new List<ViewEntity1>(); Entities2 = new List<ViewEntity2>(); } public List<ViewEntity1> Entities1 { get; set; } public List<ViewEntity2> Entities2 { get; set; } } public class ViewEntity1 { //some properties from original DB-entity you want to show } public class ViewEntity2 { } } When you create complex client-side interfaces (I do), you use some pattern for javascript on client, MVC or MVVM (I know only these). So, with MVC on client you have another model (Backbone.Model for example), which is third model in application. It is a bit much. Why don`t we use the same ViewModel model on a client (in backbone.js or another framework)? Is there a way to transfer CS-coded model to JS-coded? Like in MVVM pattern, with knockout.js, when you can do like this: in SomeAction.cshtml: <div style="display: none;" id="view_model">@Json.Encode(Model)</div> after that in Javascript-code var ViewModel = ko.mapping.fromJSON($("#view_model").get(0).innerHTML); now you can extend your ViewModel with some actions, event handlers, etc: ko.utils.extend(ViewModel, { some_function: function () { //some code } }); So, we are not building the same view model on the client again, we are transferring existing view model from server. At least, data. But knockout.js is not suitable for me, you can`t build complex UI with it, it is just data-binding. I need something more structural, like backbone.js. The only way to build ViewModel for backbone.js I can see now is re-writing same ViewModel in JS from server with hands. Is there any ways to transfer it from server? To reuse the same viewmodel on server view and client view?

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  • Visual-C++ Linker Error

    - by LordByron
    I have a class called MODEL in which public static int theMaxFrames resides. The class is defined in its own header file. theMaxFrames is accessed by a class within the MODEL class and by one function, void set_up(), which is also in the MODEL class. The Render.cpp source file contains a function which calls a function in the Direct3D.cpp source file which in turn calls the set_up() function through a MODEL object. This is the only connection between these two source files and theMaxFrames. When I try to compile my code I get the following error messages: 1Direct3D.obj : error LNK2001: unresolved external symbol "public: static int MODEL::theMaxFrames" (?theMaxFrames@MODEL@@2HA) 1Render.obj : error LNK2001: unresolved external symbol "public: static int MODEL::theMaxFrames" (?theMaxFrames@MODEL@@2HA) 1C:\Users\Byron\Documents\Visual Studio 2008\Projects\xFileViewer\Debug\xFileViewer.exe : fatal error LNK1120: 1 unresolved externals

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  • Type casting Collections using Conversion Operators

    - by Vyas Bharghava
    The below code gives me User-defined conversion must convert to or from enclosing type, while snippet #2 doesn't... It seems that a user-defined conversion routine must convert to or from the class that contains the routine. What are my alternatives? Explicit operator as extension method? Anything else? public static explicit operator ObservableCollection<ViewModel>(ObservableCollection<Model> modelCollection) { var viewModelCollection = new ObservableCollection<ViewModel>(); foreach (var model in modelCollection) { viewModelCollection.Add(new ViewModel() { Model = model }); } return viewModelCollection; } Snippet #2 public static explicit operator ViewModel(Model model) { return new ViewModel() {Model = model}; } Thanks in advance!

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  • Asp.NET MVC View with different objects

    - by user195910
    If i have a controller action "Create" that returns a view with the following as the Model type: public class PaymentModel { public Model.SummaryInformation SummaryInformation; public Model.CardDetail CardDetail; } If there is a button on this view that POST's to an action "New" and I want that action to recieve a different object e.g. public class PaymentNewModel { public Model.CardDetail CardDetail; } Is this possible? I do not want to use the same Model when the view is rendered to the Model that is POSTed

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  • Asp.net mvc 3: Strange Validation

    - by coure06
    I have applied DataAnnotation based validations to two of my properties like this [Required(ErrorMessage = "Title is required")] public string Title { get; set; } [Required(ErrorMessage = "Description is required")] public string Description { get; set; } Here is the view page's code @Html.LabelFor(model => model.Obj.Title) @Html.EditorFor(model => model.Obj.Title) @Html.LabelFor(model => model.Obj.Description) @Html.TextAreaFor(model => model.Obj.Description) The Problem is that on click of submit button, on client side (js) its only giving me error for for Title and not for the Description. But Its giving me validation error for the Description after the postback. What possible causes?

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  • FineUploader multiple instances and dynamic naming

    - by RichieMN
    I am using FineUploader 4.0.8 within a MVC4 project using the jquery wrapper. Here is an example of my js code that creates a single instance of the fineUploader and is working just fine. At this time, I have the need for more than one instance of fineUploader, but each individual control doesn't know anything about the other and they're rendered as needed on a page (I've seen previous questions using a jQuery .each, which won't work here). Currently, I can't seem to correctly render any upload buttons, probably due to having an ID duplicated or something. See below for how I'm using MVC's Razor to create unique variables and html IDs for that individual instance. Here's my current implementation where I've added the dynamic values (places where you see _@Model.{PropertyName}): // Uploader control setup var [email protected] = $('#[email protected]').fineUploader({ debug: true, template: '[email protected]', button: $("#[email protected]"), request: { endpoint: '@Url.Action("UploadFile", "Survey")', customHeaders: { Accept: 'application/json' }, params: { [email protected]: (function () { return instance; }), [email protected]: (function () { return surveyItemResultId; }), [email protected]: (function () { return itemId; }), [email protected]: (function () { return loopingCounter++; }) } }, validation: { acceptFiles: ['image/*', 'application/xls', 'application/pdf', 'text/csv', 'application/vnd.openxmlformats-officedocument.spreadsheetml.template', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', 'application/vnd.ms-excel'], allowedExtensions: ['jpeg', 'jpg', 'gif', 'png', 'bmp', 'csv', 'xls', 'xlsx', 'pdf', 'xlt', 'xltx', 'txt'], sizeLimit: 1024 * 1024 * 2.5, // 2.5MB stopOnFirstInvalidFile: false }, failedUploadTextDisplay: { mode: 'custom' }, multiple: true, text: { uploadButton: 'Select your upload file(s)' } }).on('submitted', function (event, id, filename) { $("#modal-overlay").fadeIn(); $("#modal-box").fadeIn(); [email protected]++; $(':input[type=button], :input[type=submit], :input[type=reset]').attr('disabled', 'disabled'); }).on('complete', function (event, id, filename, responseJSON) { [email protected]++; if ([email protected] == [email protected]) { $(':input[type=button], :input[type=submit], :input[type=reset]').removeAttr('disabled'); //$("#overlay").fadeOut(); $("#modal-box").fadeOut(); $("#modal-overlay").fadeOut(); } }).on('error', function (event, id, name, errorReason, xhr) { //$("#overlay").fadeOut(); alert('error: ' + errorReason); $("#modal-box").fadeOut(); $("#modal-overlay").fadeOut(); }); }); Using the same principle as above, I've added this logic to the template too. Here's part of my template: <script type="text/template" id="[email protected]"> <div class="qq-uploader-selector qq-uploader"> <div class="qq-upload-drop-area-selector qq-upload-drop-area qq-hide-dropzone"> <span>Drop files here to upload</span> What I see when I use the above code is only the drag and drop section visible, and no button. There are no js errors either. I do have an example that only has one instance of this control on it and the results are the same visible drag and drop section and no button). Any thought as to what's going on? I'll gladly update the question if you find I'm missing something helpful. Please don't just -1 me if it's something I can easily improve or fix.

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  • Django - Problem with models/manager to organise a query...

    - by user296644
    Hi, I have an application to count the number of access to an object for each website in a same database. class SimpleHit(models.Model): """ Hit is the hit counter of a given object """ content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') site = models.ForeignKey(Site) hits_total = models.PositiveIntegerField(default=0, blank=True) [...] class SimpleHitManager(models.Manager): def get_query_set(self): print self.model._meta.fields qset = super(SimpleHitManager, self).get_query_set() qset = qset.filter(hits__site=settings.SITE_ID) return qset class SimpleHitBase(models.Model): hits = generic.GenericRelation(SimpleHit) objects = SimpleHitManager() _hits = None def _db_get_hits(self, only=None): if self._hits == None: try: self._hits = self.hits.get(site=settings.SITE_ID) except SimpleHit.DoesNotExist: self._hits = SimpleHit() return self._hits @property def hits_total(self): return self._db_get_hits().hits_total [...] class Meta: abstract = True And I have a model like: class Model(SimpleHitBase): name = models.CharField(max_length=255) url = models.CharField(max_length=255) rss = models.CharField(max_length=255) creation = AutoNowAddDateTimeField() update = AutoNowDateTimeField() So, my problem is this one: when I call Model.objects.all(), I would like to have one request for the SQL (not two). In this case: one for Model in order to have information and one for the hits in order to have the counter (hits_total). This is because I cannot call directly hits.hits_total (due to SITE_ID?). I have tried select_related, but it seems to do not work... Question: - How can I add column automatically like (SELECT hits.hits_total, model.* FROM [...]) to the queryset? - Or use a functional select_related with my models? I want this model could be plugable on all other existing model. Thank you, Best regards.

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  • How to use an excel data-set for a multi-line ggplot in R?

    - by user1299887
    I have a data set in excel that I am trying to create a multiple line plot with on R. The data set contains 7 food groups and the calories consumed daily associated to the groups. As well, there is that set of data over 38 years (from 1970-2008) and I am attempting to use this data set to create a multiple line plot on R. I have tried for hours on end but can not seem to get R to recognize the variables within the data set.

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  • SQL Server and Hyper-V Dynamic Memory Part 2

    - by SQLOS Team
    Part 1 of this series was an introduction and overview of Hyper-V Dynamic Memory. This part looks at SQL Server memory management and how the SQL engine responds to changing OS memory conditions.   Part 2: SQL Server Memory Management As with any Windows process, sqlserver.exe has a virtual address space (VAS) of 4GB on 32-bit and 8TB in 64-bit editions. Pages in its VAS are mapped to pages in physical memory when the memory is committed and referenced for the first time. The collection of VAS pages that have been recently referenced is known as the Working Set. How and when SQL Server allocates virtual memory and grows its working set depends on the memory model it uses. SQL Server supports three basic memory models:   1. Conventional Memory Model   The Conventional model is the default SQL Server memory model and has the following properties: - Dynamic - can grow or shrink its working set in response to load and external (operating system) memory conditions. - OS uses 4K pages – (not to be confused with SQL Server “pages” which are 8K regions of committed memory).- Pageable - Can be paged out to disk by the operating system.   2. Locked Page Model The locked page memory model is set when SQL Server is started with "Lock Pages in Memory" privilege*. It has the following characteristics: - Dynamic - can grow or shrink its working set in the same way as the Conventional model.- OS uses 4K pages - Non-Pageable – When memory is committed it is locked in memory, meaning that it will remain backed by physical memory and will not be paged out by the operating system. A common misconception is to interpret "locked" as non-dynamic. A SQL Server instance using the locked page memory model will grow and shrink (allocate memory and release memory) in response to changing workload and OS memory conditions in the same way as it does with the conventional model.   This is an important consideration when we look at Hyper-V Dynamic Memory – “locked” memory works perfectly well with “dynamic” memory.   * Note in “Denali” (Standard Edition and above), and in SQL 2008 R2 64-bit (Enterprise and above editions) the Lock Pages in Memory privilege is all that is required to set this model. In 2008 R2 64-Bit standard edition it also requires trace flag 845 to be set, in 2008 R2 32-bit editions it requires sp_configure 'awe enabled' 1.   3. Large Page Model The Large page model is set using trace flag 834 and potentially offers a small performance boost for systems that are configured with large pages. It is characterized by: - Static - memory is allocated at startup and does not change. - OS uses large (>2MB) pages - Non-Pageable The large page model is supported with Hyper-V Dynamic Memory (and Hyper-V also supports large pages), but you get no benefit from using Dynamic Memory with this model since SQL Server memory does not grow or shrink. The rest of this article will focus on the locked and conventional SQL Server memory models.   When does SQL Server grow? For “dynamic” configurations (Conventional and Locked memory models), the sqlservr.exe process grows – allocates and commits memory from the OS – in response to a workload. As much memory is allocated as is required to optimally run the query and buffer data for future queries, subject to limitations imposed by:   - SQL Server max server memory setting. If this configuration option is set, the buffer pool is not allowed to grow to more than this value. In SQL Server 2008 this value represents single page allocations, and in “Denali” it represents any size page allocations and also managed CLR procedure allocations.   - Memory signals from OS. The operating system sets a signal on memory resource notification objects to indicate whether it has memory available or whether it is low on available memory. If there is only 32MB free for every 4GB of memory a low memory signal is set, which continues until 64MB/4GB is free. If there is 96MB/4GB free the operating system sets a high memory signal. SQL Server only allocates memory when the high memory signal is set.   To summarize, for SQL Server to grow you need three conditions: a workload, max server memory setting higher than the current allocation, high memory signals from the OS.    When does SQL Server shrink caches? SQL Server as a rule does not like to return memory to the OS, but it will shrink its caches in response to memory pressure. Memory pressure can be divided into “internal” and “external”.   - External memory pressure occurs when the operating system is running low on memory and low memory signals are set. The SQL Server Resource Monitor checks for low memory signals approximately every 5 seconds and it will attempt to free memory until the signals stop.   To free memory SQL Server does the following: ·         Frees unused memory. ·         Notifies Memory Manager Clients to release memory o   Caches – Free unreferenced cache objects. o   Buffer pool - Based on oldest access times.   The freed memory is released back to the operating system. This process continues until the low memory resource notifications stop.    - Internal memory pressure occurs when the size of different caches and allocations increase but the SQL Server process needs to keep its total memory within a target value. For example if max server memory is set and certain caches are growing large, it will cause SQL to free memory for re-use internally, but not to release memory back to the OS. If you lower the value of max server memory you will generate internal memory pressure that will cause SQL to release memory back to the OS.    Memory pressure handling has not changed much since SQL 2005 and it was described in detail in a blog post by Slava Oks.   Note that SQL Server Express is an exception to the above behavior. Unlike other editions it does not assume it is the most important process running on the system but tries to be more “desktop” friendly. It will empty its working set after a period of inactivity.   How does SQL Server respond to changing OS memory?    In SQL Server 2005 support for Hot-Add memory was introduced. This feature, available in Enterprise and above editions, allows the server to make use of any extra physical memory that was added after SQL Server started. Being able to add physical memory when the system is running is limited to specialized hardware, but with the Hyper-V Dynamic Memory feature, when new memory is allocated to a guest virtual machine, it looks like hot-add physical memory to the guest. What this means is that thanks to the hot-add memory feature, SQL Server 2005 and higher can dynamically grow if more “physical” memory is granted to a guest VM by Hyper-V dynamic memory.   SQL Server checks OS memory every second and dynamically adjusts its “target” (based on available OS memory and max server memory) accordingly.   In “Denali” Standard Edition will also have sqlserver.exe support for hot-add memory when running virtualized (i.e. detecting and acting on Hyper-V Dynamic Memory allocations).   How does a SQL Server workload in a guest VM impact Hyper-V dynamic memory scheduling?   When a SQL workload causes the sqlserver.exe process to grow its working set, the Hyper-V memory scheduler will detect memory pressure in the guest VM and add memory to it. SQL Server will then detect the extra memory and grow according to workload demand. In our tests we have seen this feedback process cause a guest VM to grow quickly in response to SQL workload - we are still working on characterizing this ramp-up.    How does SQL Server respond when Hyper-V removes memory from a guest VM through ballooning?   If pressure from other VM's cause Hyper-V Dynamic Memory to take memory away from a VM through ballooning (allocating memory with a virtual device driver and returning it to the host OS), Windows Memory Manager will page out unlocked portions of memory and signal low resource notification events. When SQL Server detects these events it will shrink memory until the low memory notifications stop (see cache shrinking description above).    This raises another question. Can we make SQL Server release memory more readily and hence behave more "dynamically" without compromising performance? In certain circumstances where the application workload is predictable it may be possible to have a job which varies "max server memory" according to need, lowering it when the engine is inactive and raising it before a period of activity. This would have limited applicaability but it is something we're looking into.   What Memory Management changes are there in SQL Server “Denali”?   In SQL Server “Denali” (aka SQL11) the Memory Manager has been re-written to be more efficient. The main changes are summarized in this post. An important change with respect to Hyper-V Dynamic Memory support is that now the max server memory setting includes any size page allocations and managed CLR procedure allocations it now represents a closer approximation to total sqlserver.exe memory usage. This makes it easier to calculate a value for max server memory, which becomes important when configuring virtual machines to work well with Hyper-V Dynamic Memory Startup and Maximum RAM settings.   Another important change is no more AWE or hot-add support for 32-bit edition. This means if you're running a 32-bit edition of Denali you're limited to a 4GB address space and will not be able to take advantage of dynamically added OS memory that wasn't present when SQL Server started (though Hyper-V Dynamic Memory is still a supported configuration).   In part 3 we’ll develop some best practices for configuring and using SQL Server with Dynamic Memory. Originally posted at http://blogs.msdn.com/b/sqlosteam/

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  • Adventures in MVVM &ndash; My ViewModel Base

    - by Brian Genisio's House Of Bilz
    More Adventures in MVVM First, I’d like to say: THIS IS NOT A NEW MVVM FRAMEWORK. I tend to believe that MVVM support code should be specific to the system you are building and the developers working on it.  I have yet to find an MVVM framework that does everything I want it to without doing too much.  Don’t get me wrong… there are some good frameworks out there.  I just like to pick and choose things that make sense for me.  I’d also like to add that some of these features only work in WPF.  As of Silveright 4, they don’t support binding to dynamic properties, so some of the capabilities are lost. That being said, I want to share my ViewModel base class with the world.  I have had several conversations with people about the problems I have solved using this ViewModel base.  A while back, I posted an article about some experiments with a “Rails Inspired ViewModel”.  What followed from those ideas was a ViewModel base class that I take with me and use in my projects.  It has a lot of features, all designed to reduce the friction in writing view models. I have put the code out on Codeplex under the project: ViewModelSupport. Finally, this article focuses on the ViewModel and only glosses over the View and the Model.  Without all three, you don’t have MVVM.  But this base class is for the ViewModel, so that is what I am focusing on. Features: Automatic Command Plumbing Property Change Notification Strongly Typed Property Getter/Setters Dynamic Properties Default Property values Derived Properties Automatic Method Execution Command CanExecute Change Notification Design-Time Detection What about Silverlight? Automatic Command Plumbing This feature takes the plumbing out of creating commands.  The common pattern for commands in a ViewModel is to have an Execute method as well as an optional CanExecute method.  To plumb that together, you create an ICommand Property, and set it in the constructor like so: Before public class AutomaticCommandViewModel { public AutomaticCommandViewModel() { MyCommand = new DelegateCommand(Execute_MyCommand, CanExecute_MyCommand); } public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } public DelegateCommand MyCommand { get; private set; } } With the base class, this plumbing is automatic and the property (MyCommand of type ICommand) is created for you.  The base class uses the convention that methods be prefixed with Execute_ and CanExecute_ in order to be plumbed into commands with the property name after the prefix.  You are left to be expressive with your behavior without the plumbing.  If you are wondering how CanExecuteChanged is raised, see the later section “Command CanExecute Change Notification”. After public class AutomaticCommandViewModel : ViewModelBase { public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } }   Property Change Notification One thing that always kills me when implementing ViewModels is how to make properties that notify when they change (via the INotifyPropertyChanged interface).  There have been many attempts to make this more automatic.  My base class includes one option.  There are others, but I feel like this works best for me. The common pattern (without my base class) is to create a private backing store for the variable and specify a getter that returns the private field.  The setter will set the private field and fire an event that notifies the change, only if the value has changed. Before public class PropertyHelpersViewModel : INotifyPropertyChanged { private string text; public string Text { get { return text; } set { if(text != value) { text = value; RaisePropertyChanged("Text"); } } } protected void RaisePropertyChanged(string propertyName) { var handlers = PropertyChanged; if(handlers != null) handlers(this, new PropertyChangedEventArgs(propertyName)); } public event PropertyChangedEventHandler PropertyChanged; } This way of defining properties is error-prone and tedious.  Too much plumbing.  My base class eliminates much of that plumbing with the same functionality: After public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get<string>("Text"); } set { Set("Text", value);} } }   Strongly Typed Property Getters/Setters It turns out that we can do better than that.  We are using a strongly typed language where the use of “Magic Strings” is often frowned upon.  Lets make the names in the getters and setters strongly typed: A refinement public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get(() => Text); } set { Set(() => Text, value); } } }   Dynamic Properties In C# 4.0, we have the ability to program statically OR dynamically.  This base class lets us leverage the powerful dynamic capabilities in our ecosystem. (This is how the automatic commands are implemented, BTW)  By calling Set(“Foo”, 1), you have now created a dynamic property called Foo.  It can be bound against like any static property.  The opportunities are endless.  One great way to exploit this behavior is if you have a customizable view engine with templates that bind to properties defined by the user.  The base class just needs to create the dynamic properties at runtime from information in the model, and the custom template can bind even though the static properties do not exist. All dynamic properties still benefit from the notifiable capabilities that static properties do. For any nay-sayers out there that don’t like using the dynamic features of C#, just remember this: the act of binding the View to a ViewModel is dynamic already.  Why not exploit it?  Get over it :) Just declare the property dynamically public class DynamicPropertyViewModel : ViewModelBase { public DynamicPropertyViewModel() { Set("Foo", "Bar"); } } Then reference it normally <TextBlock Text="{Binding Foo}" />   Default Property Values The Get() method also allows for default properties to be set.  Don’t set them in the constructor.  Set them in the property and keep the related code together: public string Text { get { return Get(() => Text, "This is the default value"); } set { Set(() => Text, value);} }   Derived Properties This is something I blogged about a while back in more detail.  This feature came from the chaining of property notifications when one property affects the results of another, like this: Before public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); RaisePropertyChanged("Percentage"); RaisePropertyChanged("Output"); } } public int Percentage { get { return (int)(100 * Score); } } public string Output { get { return "You scored " + Percentage + "%."; } } } The problem is: The setter for Score has to be responsible for notifying the world that Percentage and Output have also changed.  This, to me, is backwards.    It certainly violates the “Single Responsibility Principle.” I have been bitten in the rear more than once by problems created from code like this.  What we really want to do is invert the dependency.  Let the Percentage property declare that it changes when the Score Property changes. After public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public int Percentage { get { return (int)(100 * Score); } } [DependsUpon("Percentage")] public string Output { get { return "You scored " + Percentage + "%."; } } }   Automatic Method Execution This one is extremely similar to the previous, but it deals with method execution as opposed to property.  When you want to execute a method triggered by property changes, let the method declare the dependency instead of the other way around. Before public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); WhenScoreChanges(); } } public void WhenScoreChanges() { // Handle this case } } After public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public void WhenScoreChanges() { // Handle this case } }   Command CanExecute Change Notification Back to Commands.  One of the responsibilities of commands that implement ICommand – it must fire an event declaring that CanExecute() needs to be re-evaluated.  I wanted to wait until we got past a few concepts before explaining this behavior.  You can use the same mechanism here to fire off the change.  In the CanExecute_ method, declare the property that it depends upon.  When that property changes, the command will fire a CanExecuteChanged event, telling the View to re-evaluate the state of the command.  The View will make appropriate adjustments, like disabling the button. DependsUpon works on CanExecute methods as well public class CanExecuteViewModel : ViewModelBase { public void Execute_MakeLower() { Output = Input.ToLower(); } [DependsUpon("Input")] public bool CanExecute_MakeLower() { return !string.IsNullOrWhiteSpace(Input); } public string Input { get { return Get(() => Input); } set { Set(() => Input, value);} } public string Output { get { return Get(() => Output); } set { Set(() => Output, value); } } }   Design-Time Detection If you want to add design-time data to your ViewModel, the base class has a property that lets you ask if you are in the designer.  You can then set some default values that let your designer see what things might look like in runtime. Use the IsInDesignMode property public DependantPropertiesViewModel() { if(IsInDesignMode) { Score = .5; } }   What About Silverlight? Some of the features in this base class only work in WPF.  As of version 4, Silverlight does not support binding to dynamic properties.  This, in my opinion, is a HUGE limitation.  Not only does it keep you from using many of the features in this ViewModel, it also keeps you from binding to ViewModels designed in IronRuby.  Does this mean that the base class will not work in Silverlight?  No.  Many of the features outlined in this article WILL work.  All of the property abstractions are functional, as long as you refer to them statically in the View.  This, of course, means that the automatic command hook-up doesn’t work in Silverlight.  You need to plumb it to a static property in order for the Silverlight View to bind to it.  Can I has a dynamic property in SL5?     Good to go? So, that concludes the feature explanation of my ViewModel base class.  Feel free to take it, fork it, whatever.  It is hosted on CodePlex.  When I find other useful additions, I will add them to the public repository.  I use this base class every day.  It is mature, and well tested.  If, however, you find any problems with it, please let me know!  Also, feel free to suggest patches to me via the CodePlex site.  :)

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  • SharePoint Apps and Windows Azure

    - by ScottGu
    Last Monday I had an opportunity to present as part of the keynote of this year’s SharePoint Conference.  My segment of the keynote covered the new SharePoint Cloud App Model we are introducing as part of the upcoming SharePoint 2013 and Office 365 releases.  This new app model for SharePoint is additive to the full trust solutions developers write today, and is built around three core tenants: Simplifying the development model and making it consistent between the on-premises version of SharePoint and SharePoint Online provided with Office 365. Making the execution model loosely coupled – and enabling developers to build apps and write code that can run outside of the core SharePoint service. This makes it easy to deploy SharePoint apps using Windows Azure, and avoid having to worry about breaking SharePoint and the apps within it when something is upgraded.  This new loosely coupled model also enables developers to write SharePoint applications that can leverage the full capabilities of the .NET Framework – including ASP.NET Web Forms 4.5, ASP.NET MVC 4, ASP.NET Web API, EF 5, Async, and more. Implementing this loosely coupled model using standard web protocols – like OAuth, JSON, and REST APIs – that enable developers to re-use skills and tools, and easily integrate SharePoint with Web and Mobile application architectures. A video of my talk + demos is now available to watch online: In the talk I walked through building an app from scratch – it showed off how easy it is to build solutions using new SharePoint application, and highlighted a web + workflow + mobile scenario that integrates SharePoint with code hosted on Windows Azure (all built using Visual Studio 2012 and ASP.NET 4.5 – including MVC and Web API). The new SharePoint Cloud App Model is something that I think is pretty exciting, and it is going to make it a lot easier to build SharePoint apps using the full power of both Windows Azure and the .NET Framework.  Using Windows Azure to easily extend SaaS based solutions like Office 365 is also a really natural fit and one that is going to offer a bunch of great developer opportunities.  Hope this helps, Scott  P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • iPhone Open GL ES using FBX - How do I import animations from FBX into iPhone?

    - by Dominic Tancredi
    I've been researching this extensively. We have a game that's 90% complete, using custom game logic in iPhone 4.0. We've been asked to import a 3D model and have it animate when various events happen in the game. I've put together an OpenGL view (based on Eagl and several examples), and used Blender to import the model, as well as Jeff LeMarche's script to export the .h file. After much trial, it worked, and I was able to show a rotating model (unskinned). However, the 3d artist hadn't UV unwrapped the model, so provided me a new model, this one as a Maya file, along with animation in a FBX format, a .obj file, and .tga texture unwrapped. My question is : how can I use FBX inside OpenGL ES inside iPhone to run through animations? And what's the pipeline to get this Maya file into Blender to be able to create a .h file. I've tried the obj2opengl however the model is missing normals (did it have it in the first place?) and the skin isn't applying at all (possibly a code issue, something I think I can fix). I'm trying to use Jeff LeMarche's animation tutorial but can't figure out how to get the model files into a proper .h file for use. Any advice?

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  • 3DS Max 2012 OBJ file import missing polygons

    - by Vit
    I started learning OpenGL. I got to a point I want to import some "real" objects. After "Googling" I decided I will go with OBJ file for start, since it is simple to understand, and there are plenty of tutorials on how to read them properly. I have from university access to 3DS Max 2012. So I tried to create very simple model (just deformated cube) and exporting it using OBJ file, just to vertices and triangles for the moment, without textures, so I can examine its structure by myself. But if I imported it right back to 3DS from OBJ file, now it renders somewhat strange, like its smoothen, and with lightsource, even I have none in scene. But the geometry, its wireframe is intact. So I thought maybe it is problem of exporting only vertices and triangles so I downloaded Enterprise-D model from internet, exported with everything on (normals, textures everything), and again imported it. Now, some polygons are missing. So, I want to ask, am I doing something terribly wrong, or is there some incompatibility issue between .max and .obj file ? Even it is only simple textured model without any lightsources, animation etc.? Thanks. Edit: I tried objects with MeshLab, the first, deformated cube was absolutelly OK. But still bothers me that 3DS Max doesen´t render it properly. In Enterprise-D model, there are polygons missing even in MeshLab. I uploaded rar archive with .max model of Enterprise, same .obj model exported from 3DS, and obj model of deformated cube. Download here (2.5 MB, filesonic).

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