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  • Best practices for logging and tracing in .NET

    - by Levidad
    I've been reading a lot about tracing and logging, trying to find some golden rule for best practices in the matter, but there isn't any. People say that good programmers produce good tracing, but put it that way and it has to come from experience. I've also read similar questions in here and through the internet and they are not really the same thing I am asking or do not have a satisfying answer, maybe because the questions lack some detail. So, folks say that tracing should sort of replicate the experience of debugging the application in cases where you can't attach a debugger. It should provide enough context so that you can see which path is taken at each control point in the application. Going deeper, you can even distinguish between tracing and event logging, in that "event logging is different from tracing in that it captures major states rather than detailed flow of control". Now, say I want to do my tracing and logging using only the standard .NET classes, those in the System.Diagnostics namespace. I figured that the TraceSource class is better for the job than the static Trace class, because I want to differentiate among the trace levels and using the TraceSource class I can pass in a parameter informing the event type, while using the Trace class I must use Trace.WriteLineIf and then verify things like SourceSwitch.TraceInformation and SourceSwitch.TraceErrors, and it doesn't even have properties like TraceVerbose or TraceStart. With all that in mind, would you consider a good practice to do as follows: Trace a "Start" event when begining a method, which should represent a single logical operation or a pipeline, along with a string representation of the parameter values passed in to the method. Trace an "Information" event when inserting an item into the database. Trace an "Information" event when taking one path or another in an important if/else statement. Trace a "Critical" or "Error" in a catch block depending on weather this is a recoverable error. Trace a "Stop" event when finishing the execution of the method. And also, please clarify when best to trace Verbose and Warning event types. If you have examples of code with nice trace/logging and are willing to share, that would be excelent. Note: I've found some good information here, but still not what I am looking for: http://msdn.microsoft.com/en-us/magazine/ff714589.aspx Thanks in advance!

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  • Open GL polygons not displaying

    - by Darestium
    I have tried to follow nehe's opengl tutorial lesson 2. I use sfml for my window creation. The problem I have is that both the triangle and the quad don't show up on the screen: #include <SFML/System.hpp> #include <SFML/Window.hpp> #include <iostream> void processEvents(sf::Window *app); void processInput(sf::Window *app, const sf::Input &input); void renderCube(sf::Window *app, sf::Clock *clock); void renderGlScene(sf::Window *app); void init(); int main() { sf::Window app(sf::VideoMode(800, 600, 32), "Nehe Lesson 2"); app.UseVerticalSync(false); init(); while (app.IsOpened()) { processEvents(&app); renderGlScene(&app); app.Display(); } return EXIT_SUCCESS; } void init() { glClearDepth(1.f); glClearColor(0.f, 0.f, 0.f, 0.f); // Enable z-buffer and read and write glEnable(GL_DEPTH_TEST); glDepthMask(GL_TRUE); // Setup a perpective projection glMatrixMode(GL_MODELVIEW); glLoadIdentity(); gluPerspective(45.f, 1.f, 1.f, 500.f); glShadeModel(GL_SMOOTH); } void processEvents(sf::Window *app) { sf::Event event; while (app->GetEvent(event)) { if (event.Type == sf::Event::Closed) { app->Close(); } if (event.Type == sf::Event::KeyPressed && event.Key.Code == sf::Key::Escape) { app->Close(); } } } void renderGlScene(sf::Window *app) { app->SetActive(); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear the screen and the depth buffer glLoadIdentity(); // Reset the view glTranslatef(-1.5f, 0.0f, -6.0f); // Move Left 1.5 units and into the screen 6.0 glBegin(GL_TRIANGLES); glVertex3f( 0.0f, 1.0f, 0.0f); // Top glVertex3f(-1.0,-1.0f, 0.0f); // Bottom Left glVertex3f( 1.0f,-1.0f, 0.0f); // Bottom Right glEnd(); glTranslatef(3.0f, 0.0f, 0.0f); glBegin(GL_QUADS); // Draw a quad glVertex3f(-1.0f, 1.0f, 0.0f); glVertex3f( 1.0f, 1.0f, 0.0f); glVertex3f( 1.0f,-1.0f, 0.0f); glVertex3f(-1.0f,-1.0f, 0.0f); glEnd(); } I would greatly appreciate it if someone could help me resolve my issue.

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  • Parallelism in .NET – Part 9, Configuration in PLINQ and TPL

    - by Reed
    Parallel LINQ and the Task Parallel Library contain many options for configuration.  Although the default configuration options are often ideal, there are times when customizing the behavior is desirable.  Both frameworks provide full configuration support. When working with Data Parallelism, there is one primary configuration option we often need to control – the number of threads we want the system to use when parallelizing our routine.  By default, PLINQ and the TPL both use the ThreadPool to schedule tasks.  Given the major improvements in the ThreadPool in CLR 4, this default behavior is often ideal.  However, there are times that the default behavior is not appropriate.  For example, if you are working on multiple threads simultaneously, and want to schedule parallel operations from within both threads, you might want to consider restricting each parallel operation to using a subset of the processing cores of the system.  Not doing this might over-parallelize your routine, which leads to inefficiencies from having too many context switches. In the Task Parallel Library, configuration is handled via the ParallelOptions class.  All of the methods of the Parallel class have an overload which accepts a ParallelOptions argument. We configure the Parallel class by setting the ParallelOptions.MaxDegreeOfParallelism property.  For example, let’s revisit one of the simple data parallel examples from Part 2: Parallel.For(0, pixelData.GetUpperBound(0), row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re looping through an image, and calling a method on each pixel in the image.  If this was being done on a separate thread, and we knew another thread within our system was going to be doing a similar operation, we likely would want to restrict this to using half of the cores on the system.  This could be accomplished easily by doing: var options = new ParallelOptions(); options.MaxDegreeOfParallelism = Math.Max(Environment.ProcessorCount / 2, 1); Parallel.For(0, pixelData.GetUpperBound(0), options, row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); Now, we’re restricting this routine to using no more than half the cores in our system.  Note that I included a check to prevent a single core system from supplying zero; without this check, we’d potentially cause an exception.  I also did not hard code a specific value for the MaxDegreeOfParallelism property.  One of our goals when parallelizing a routine is allowing it to scale on better hardware.  Specifying a hard-coded value would contradict that goal. Parallel LINQ also supports configuration, and in fact, has quite a few more options for configuring the system.  The main configuration option we most often need is the same as our TPL option: we need to supply the maximum number of processing threads.  In PLINQ, this is done via a new extension method on ParallelQuery<T>: ParallelEnumerable.WithDegreeOfParallelism. Let’s revisit our declarative data parallelism sample from Part 6: double min = collection.AsParallel().Min(item => item.PerformComputation()); Here, we’re performing a computation on each element in the collection, and saving the minimum value of this operation.  If we wanted to restrict this to a limited number of threads, we would add our new extension method: int maxThreads = Math.Max(Environment.ProcessorCount / 2, 1); double min = collection .AsParallel() .WithDegreeOfParallelism(maxThreads) .Min(item => item.PerformComputation()); This automatically restricts the PLINQ query to half of the threads on the system. PLINQ provides some additional configuration options.  By default, PLINQ will occasionally revert to processing a query in parallel.  This occurs because many queries, if parallelized, typically actually cause an overall slowdown compared to a serial processing equivalent.  By analyzing the “shape” of the query, PLINQ often decides to run a query serially instead of in parallel.  This can occur for (taken from MSDN): Queries that contain a Select, indexed Where, indexed SelectMany, or ElementAt clause after an ordering or filtering operator that has removed or rearranged original indices. Queries that contain a Take, TakeWhile, Skip, SkipWhile operator and where indices in the source sequence are not in the original order. Queries that contain Zip or SequenceEquals, unless one of the data sources has an originally ordered index and the other data source is indexable (i.e. an array or IList(T)). Queries that contain Concat, unless it is applied to indexable data sources. Queries that contain Reverse, unless applied to an indexable data source. If the specific query follows these rules, PLINQ will run the query on a single thread.  However, none of these rules look at the specific work being done in the delegates, only at the “shape” of the query.  There are cases where running in parallel may still be beneficial, even if the shape is one where it typically parallelizes poorly.  In these cases, you can override the default behavior by using the WithExecutionMode extension method.  This would be done like so: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .Select(i => i.PerformComputation()) .Reverse(); Here, the default behavior would be to not parallelize the query unless collection implemented IList<T>.  We can force this to run in parallel by adding the WithExecutionMode extension method in the method chain. Finally, PLINQ has the ability to configure how results are returned.  When a query is filtering or selecting an input collection, the results will need to be streamed back into a single IEnumerable<T> result.  For example, the method above returns a new, reversed collection.  In this case, the processing of the collection will be done in parallel, but the results need to be streamed back to the caller serially, so they can be enumerated on a single thread. This streaming introduces overhead.  IEnumerable<T> isn’t designed with thread safety in mind, so the system needs to handle merging the parallel processes back into a single stream, which introduces synchronization issues.  There are two extremes of how this could be accomplished, but both extremes have disadvantages. The system could watch each thread, and whenever a thread produces a result, take that result and send it back to the caller.  This would mean that the calling thread would have access to the data as soon as data is available, which is the benefit of this approach.  However, it also means that every item is introducing synchronization overhead, since each item needs to be merged individually. On the other extreme, the system could wait until all of the results from all of the threads were ready, then push all of the results back to the calling thread in one shot.  The advantage here is that the least amount of synchronization is added to the system, which means the query will, on a whole, run the fastest.  However, the calling thread will have to wait for all elements to be processed, so this could introduce a long delay between when a parallel query begins and when results are returned. The default behavior in PLINQ is actually between these two extremes.  By default, PLINQ maintains an internal buffer, and chooses an optimal buffer size to maintain.  Query results are accumulated into the buffer, then returned in the IEnumerable<T> result in chunks.  This provides reasonably fast access to the results, as well as good overall throughput, in most scenarios. However, if we know the nature of our algorithm, we may decide we would prefer one of the other extremes.  This can be done by using the WithMergeOptions extension method.  For example, if we know that our PerformComputation() routine is very slow, but also variable in runtime, we may want to retrieve results as they are available, with no bufferring.  This can be done by changing our above routine to: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .WithMergeOptions(ParallelMergeOptions.NotBuffered) .Select(i => i.PerformComputation()) .Reverse(); On the other hand, if are already on a background thread, and we want to allow the system to maximize its speed, we might want to allow the system to fully buffer the results: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .WithMergeOptions(ParallelMergeOptions.FullyBuffered) .Select(i => i.PerformComputation()) .Reverse(); Notice, also, that you can specify multiple configuration options in a parallel query.  By chaining these extension methods together, we generate a query that will always run in parallel, and will always complete before making the results available in our IEnumerable<T>.

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  • Is it possible to call Javascript's onsubmit event programatically on a form?

    - by hoyhoy
    In Ruby on Rails, I'm attempting to update the innerHTML of a div tag using the form_remote_tag helper. This update happens whenever an associated select tag receives an onchange event. The problem is, <select onchange="this.form.submit();">; doesn't work. Nor does document.forms[0].submit(). The only way to get the onsubmit code generated in the form_remote_tag to execute is to create a hidden submit button, and invoke the click method on the button from the select tag. Here's a working ERb partial example. <% form_remote_tag :url => product_path, :update => 'content', :method => 'get' do -%> <% content_tag :div, :id => 'content' do -%> <%= select_tag :update, options_for_select([["foo", 1], ["bar", 2]]), :onchange => "this.form.commit.click" %> <%= submit_tag 'submit_button', :style => "display: none" %> <% end %> <% end %> What I want to do is something like this, but it doesn't work. <% form_remote_tag :url => product_path, :update => 'content', :method => 'get' do -%> <% content_tag :div, :id => 'content' do -%> # the following line does not work <%= select_tag :update, options_for_select([["foo", 1], ["bar", 2]]), :onchange => "this.form.onsubmit()" %> <% end %> <% end %> So, is there any way to remove the invisible submit button for this use case? There seems to be some confusion. So, let me explain. The basic problem is that submit() doesn't call the onsubmit() code rendered into the form. The actual HTML form that Rails renders from this ERb looks like this: <form action="/products/1" method="post" onsubmit="new Ajax.Updater('content', '/products/1', {asynchronous:true, evalScripts:true, method:'get', parameters:Form.serialize(this)}); return false;"> <div style="margin:0;padding:0"> <input name="authenticity_token" type="hidden" value="4eacf78eb87e9262a0b631a8a6e417e9a5957cab" /> </div> <div id="content"> <select id="update" name="update" onchange="this.form.commit.click"> <option value="1">foo</option> <option value="2">bar</option> </select> <input name="commit" style="display: none" type="submit" value="submit_button" /> </div> </form> I want to axe the invisible submit button, but using a straight form.submit appears to not work. So, I need some way to call the form's onsubmit event code. Update: Orion Edwards solution would work if there wasn't a return(false); generated by Rails. I'm not sure which is worse though, sending a phantom click to an invisible submit button or calling eval on the getAttribute('onsubmit') call after removing the return call with a javascript string replacement!

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  • Metro: Creating a Master/Detail View with a WinJS ListView Control

    - by Stephen.Walther
    The goal of this blog entry is to explain how you can create a simple master/detail view by using the WinJS ListView and Template controls. In particular, I explain how you can use a ListView control to display a list of movies and how you can use a Template control to display the details of the selected movie. Creating a master/detail view requires completing the following four steps: Create the data source – The data source contains the list of movies. Declare the ListView control – The ListView control displays the entire list of movies. It is the master part of the master/detail view. Declare the Details Template control – The Details Template control displays the details for the selected movie. It is the details part of the master/detail view. Handle the selectionchanged event – You handle the selectionchanged event to display the details for a movie when a new movie is selected. Creating the Data Source There is nothing special about our data source. We initialize a WinJS.Binding.List object to represent a list of movies: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })(); The data source is exposed to the rest of our application with the name ListViewDemos.movies. Declaring the ListView Control The ListView control is declared with the following markup: <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> The data-win-options attribute is used to set the following properties of the ListView control: itemDataSource – The ListView is bound to the list of movies which we created in the previous section. Notice that the ListView is bound to ListViewDemos.movies.dataSource and not just ListViewDemos.movies. itemTemplate – The item template contains the template used for rendering each item in the ListView. The markup for this template is included below. tabBehavior – This enumeration determines what happens when you tap or click on an item in the ListView. The possible values are directSelect, toggleSelect, invokeOnly, none. Because we want to handle the selectionchanged event, we set tapBehavior to the value directSelect. selectionMode – This enumeration determines whether you can select multiple items or only a single item. The possible values are none, single, multi. In the code above, this property is set to the value single. layout – You can use ListLayout or GridLayout with a ListView. If you want to display a vertical ListView, then you should select ListLayout. You must associate a ListView with an item template if you want to render anything interesting. The ListView above is associated with an item template named #masterItemTemplate. Here’s the markup for the masterItemTemplate: <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> This template simply renders the title of each movie. Declaring the Details Template Control The details part of the master/detail view is created with the help of a Template control. Here’s the markup used to declare the Details Template control: <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> The Details Template control displays the movie title and director.   Handling the selectionchanged Event The ListView control can raise two types of events: the iteminvoked and selectionchanged events. The iteminvoked event is raised when you click on a ListView item. The selectionchanged event is raised when one or more ListView items are selected. When you set the tapBehavior property of the ListView control to the value “directSelect” then tapping or clicking a list item raised both the iteminvoked and selectionchanged event. Tapping a list item causes the item to be selected and the item appears with a checkmark. In our code, we handle the selectionchanged event to update the movie details Template when you select a new movie. Here’s the code from the default.js file used to handle the selectionchanged event: var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); The code above sets up an event handler (listener) for the selectionchanged event. The event handler first verifies that an item has been selected in the ListView (selection.count() > 0). Next, the details for the movie are rendered using the movie details Template (we created this Template in the previous section). The Complete Code For the sake of completeness, I’ve included the complete code for the master/detail view below. I’ve included both the default.html, default.js, and movies.js files. Here is the final code for the default.html file: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>ListViewMasterDetail</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- ListViewMasterDetail references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/movies.js"></script> <style type="text/css"> body { font-size: xx-large; } .movie { padding: 5px; } #masterDetail { display: -ms-box; } #movieList { width: 300px; margin: 20px; } #movieDetails { margin: 20px; } </style> </head> <body> <!-- Templates --> <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> <!-- Master/Detail --> <div id="masterDetail"> <!-- Master --> <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> <!-- Detail --> <div id="movieDetails"></div> </div> </body> </html> Here is the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); } }; app.start(); })();   Here is the movies.js file: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })();   Summary The purpose of this blog entry was to describe how to create a simple master/detail view by taking advantage of the WinJS ListView control. We handled the selectionchanged event of the ListView control to display movie details when you select a movie in the ListView.

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  • Metro: Creating a Master/Detail View with a WinJS ListView Control

    - by Stephen.Walther
    The goal of this blog entry is to explain how you can create a simple master/detail view by using the WinJS ListView and Template controls. In particular, I explain how you can use a ListView control to display a list of movies and how you can use a Template control to display the details of the selected movie. Creating a master/detail view requires completing the following four steps: Create the data source – The data source contains the list of movies. Declare the ListView control – The ListView control displays the entire list of movies. It is the master part of the master/detail view. Declare the Details Template control – The Details Template control displays the details for the selected movie. It is the details part of the master/detail view. Handle the selectionchanged event – You handle the selectionchanged event to display the details for a movie when a new movie is selected. Creating the Data Source There is nothing special about our data source. We initialize a WinJS.Binding.List object to represent a list of movies: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })(); The data source is exposed to the rest of our application with the name ListViewDemos.movies. Declaring the ListView Control The ListView control is declared with the following markup: <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> The data-win-options attribute is used to set the following properties of the ListView control: itemDataSource – The ListView is bound to the list of movies which we created in the previous section. Notice that the ListView is bound to ListViewDemos.movies.dataSource and not just ListViewDemos.movies. itemTemplate – The item template contains the template used for rendering each item in the ListView. The markup for this template is included below. tabBehavior – This enumeration determines what happens when you tap or click on an item in the ListView. The possible values are directSelect, toggleSelect, invokeOnly, none. Because we want to handle the selectionchanged event, we set tapBehavior to the value directSelect. selectionMode – This enumeration determines whether you can select multiple items or only a single item. The possible values are none, single, multi. In the code above, this property is set to the value single. layout – You can use ListLayout or GridLayout with a ListView. If you want to display a vertical ListView, then you should select ListLayout. You must associate a ListView with an item template if you want to render anything interesting. The ListView above is associated with an item template named #masterItemTemplate. Here’s the markup for the masterItemTemplate: <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> This template simply renders the title of each movie. Declaring the Details Template Control The details part of the master/detail view is created with the help of a Template control. Here’s the markup used to declare the Details Template control: <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> The Details Template control displays the movie title and director.   Handling the selectionchanged Event The ListView control can raise two types of events: the iteminvoked and selectionchanged events. The iteminvoked event is raised when you click on a ListView item. The selectionchanged event is raised when one or more ListView items are selected. When you set the tapBehavior property of the ListView control to the value “directSelect” then tapping or clicking a list item raised both the iteminvoked and selectionchanged event. Tapping a list item causes the item to be selected and the item appears with a checkmark. In our code, we handle the selectionchanged event to update the movie details Template when you select a new movie. Here’s the code from the default.js file used to handle the selectionchanged event: var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); The code above sets up an event handler (listener) for the selectionchanged event. The event handler first verifies that an item has been selected in the ListView (selection.count() > 0). Next, the details for the movie are rendered using the movie details Template (we created this Template in the previous section). The Complete Code For the sake of completeness, I’ve included the complete code for the master/detail view below. I’ve included both the default.html, default.js, and movies.js files. Here is the final code for the default.html file: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>ListViewMasterDetail</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- ListViewMasterDetail references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/movies.js"></script> <style type="text/css"> body { font-size: xx-large; } .movie { padding: 5px; } #masterDetail { display: -ms-box; } #movieList { width: 300px; margin: 20px; } #movieDetails { margin: 20px; } </style> </head> <body> <!-- Templates --> <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> <!-- Master/Detail --> <div id="masterDetail"> <!-- Master --> <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> <!-- Detail --> <div id="movieDetails"></div> </div> </body> </html> Here is the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); } }; app.start(); })();   Here is the movies.js file: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })();   Summary The purpose of this blog entry was to describe how to create a simple master/detail view by taking advantage of the WinJS ListView control. We handled the selectionchanged event of the ListView control to display movie details when you select a movie in the ListView.

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  • A WPF Image Button

    - by psheriff
    Instead of a normal button with words, sometimes you want a button that is just graphical. Yes, you can put an Image control in the Content of a normal Button control, but you still have the button outline, and trying to change the style can be rather difficult. Instead I like creating a user control that simulates a button, but just accepts an image. Figure 1 shows an example of three of these custom user controls to represent minimize, maximize and close buttons for a borderless window. Notice the highlighted image button has a gray rectangle around it. You will learn how to highlight using the VisualStateManager in this blog post.Figure 1: Creating a custom user control for things like image buttons gives you complete control over the look and feel.I would suggest you read my previous blog post on creating a custom Button user control as that is a good primer for what I am going to expand upon in this blog post. You can find this blog post at http://weblogs.asp.net/psheriff/archive/2012/08/10/create-your-own-wpf-button-user-controls.aspx.The User ControlThe XAML for this image button user control contains just a few controls, plus a Visual State Manager. The basic outline of the user control is shown below:<Border Grid.Row="0"        Name="borMain"        Style="{StaticResource pdsaButtonImageBorderStyle}"        MouseEnter="borMain_MouseEnter"        MouseLeave="borMain_MouseLeave"        MouseLeftButtonDown="borMain_MouseLeftButtonDown">  <VisualStateManager.VisualStateGroups>  ... MORE XAML HERE ...  </VisualStateManager.VisualStateGroups>  <Image Style="{StaticResource pdsaButtonImageImageStyle}"         Visibility="{Binding Path=Visibility}"         Source="{Binding Path=ImageUri}"         ToolTip="{Binding Path=ToolTip}" /></Border>There is a Border control named borMain and a single Image control in this user control. That is all that is needed to display the buttons shown in Figure 1. The definition for this user control is in a DLL named PDSA.WPF. The Style definitions for both the Border and the Image controls are contained in a resource dictionary names PDSAButtonStyles.xaml. Using a resource dictionary allows you to create a few different resource dictionaries, each with a different theme for the buttons.The Visual State ManagerTo display the highlight around the button as your mouse moves over the control, you will need to add a Visual State Manager group. Two different states are needed; MouseEnter and MouseLeave. In the MouseEnter you create a ColorAnimation to modify the BorderBrush color of the Border control. You specify the color to animate as “DarkGray”. You set the duration to less than a second. The TargetName of this storyboard is the name of the Border control “borMain” and since we are specifying a single color, you need to set the TargetProperty to “BorderBrush.Color”. You do not need any storyboard for the MouseLeave state. Leaving this VisualState empty tells the Visual State Manager to put everything back the way it was before the MouseEnter event.<VisualStateManager.VisualStateGroups>  <VisualStateGroup Name="MouseStates">    <VisualState Name="MouseEnter">      <Storyboard>        <ColorAnimation             To="DarkGray"            Duration="0:0:00.1"            Storyboard.TargetName="borMain"            Storyboard.TargetProperty="BorderBrush.Color" />      </Storyboard>    </VisualState>    <VisualState Name="MouseLeave" />  </VisualStateGroup></VisualStateManager.VisualStateGroups>Writing the Mouse EventsTo trigger the Visual State Manager to run its storyboard in response to the specified event, you need to respond to the MouseEnter event on the Border control. In the code behind for this event call the GoToElementState() method of the VisualStateManager class exposed by the user control. To this method you will pass in the target element (“borMain”) and the state (“MouseEnter”). The VisualStateManager will then run the storyboard contained within the defined state in the XAML.private void borMain_MouseEnter(object sender,  MouseEventArgs e){  VisualStateManager.GoToElementState(borMain,    "MouseEnter", true);}You also need to respond to the MouseLeave event. In this event you call the VisualStateManager as well, but specify “MouseLeave” as the state to go to.private void borMain_MouseLeave(object sender, MouseEventArgs e){  VisualStateManager.GoToElementState(borMain,     "MouseLeave", true);}The Resource DictionaryBelow is the definition of the PDSAButtonStyles.xaml resource dictionary file contained in the PDSA.WPF DLL. This dictionary can be used as the default look and feel for any image button control you add to a window. <ResourceDictionary  ... >  <!-- ************************* -->  <!-- ** Image Button Styles ** -->  <!-- ************************* -->  <!-- Image/Text Button Border -->  <Style TargetType="Border"         x:Key="pdsaButtonImageBorderStyle">    <Setter Property="Margin"            Value="4" />    <Setter Property="Padding"            Value="2" />    <Setter Property="BorderBrush"            Value="Transparent" />    <Setter Property="BorderThickness"            Value="1" />    <Setter Property="VerticalAlignment"            Value="Top" />    <Setter Property="HorizontalAlignment"            Value="Left" />    <Setter Property="Background"            Value="Transparent" />  </Style>  <!-- Image Button -->  <Style TargetType="Image"         x:Key="pdsaButtonImageImageStyle">    <Setter Property="Width"            Value="40" />    <Setter Property="Margin"            Value="6" />    <Setter Property="VerticalAlignment"            Value="Top" />    <Setter Property="HorizontalAlignment"            Value="Left" />  </Style></ResourceDictionary>Using the Button ControlOnce you make a reference to the PDSA.WPF DLL from your WPF application you will see the “PDSAucButtonImage” control appear in your Toolbox. Drag and drop the button onto a Window or User Control in your application. I have not referenced the PDSAButtonStyles.xaml file within the control itself so you do need to add a reference to this resource dictionary somewhere in your application such as in the App.xaml.<Application.Resources>  <ResourceDictionary>    <ResourceDictionary.MergedDictionaries>      <ResourceDictionary         Source="/PDSA.WPF;component/PDSAButtonStyles.xaml" />    </ResourceDictionary.MergedDictionaries>  </ResourceDictionary></Application.Resources>This will give your buttons a default look and feel unless you override that dictionary on a specific Window or User Control or on an individual button. After you have given a global style to your application and you drag your image button onto a window, the following will appear in your XAML window.<my:PDSAucButtonImage ... />There will be some other attributes set on the above XAML, but you simply need to set the x:Name, the ToolTip and ImageUri properties. You will also want to respond to the Click event procedure in order to associate an action with clicking on this button. In the sample code you download for this blog post you will find the declaration of the Minimize button to be the following:<my:PDSAucButtonImage       x:Name="btnMinimize"       Click="btnMinimize_Click"       ToolTip="Minimize Application"       ImageUri="/PDSA.WPF;component/Images/Minus.png" />The ImageUri property is a dependency property in the PDSAucButtonImage user control. The x:Name and the ToolTip we get for free. You have to create the Click event procedure yourself. This is also created in the PDSAucButtonImage user control as follows:private void borMain_MouseLeftButtonDown(object sender,  MouseButtonEventArgs e){  RaiseClick(e);}public delegate void ClickEventHandler(object sender,  RoutedEventArgs e);public event ClickEventHandler Click;protected void RaiseClick(RoutedEventArgs e){  if (null != Click)    Click(this, e);}Since a Border control does not have a Click event you will create one by using the MouseLeftButtonDown on the border to fire an event you create called “Click”.SummaryCreating your own image button control can be done in a variety of ways. In this blog post I showed you how to create a custom user control and simulate a button using a Border and Image control. With just a little bit of code to respond to the MouseLeftButtonDown event on the border you can raise your own Click event. Dependency properties, such as ImageUri, allow you to set attributes on your custom user control. Feel free to expand on this button by adding additional dependency properties, change the resource dictionary, and even the animation to make this button look and act like you want.NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A WPF Image  Button” from the drop down list.

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  • AIX Checklist for stable obiee deployment

    - by user554629
    Common AIX configuration issues     ( last updated 27 Aug 2012 ) OBIEE is a complicated system with many moving parts and connection points.The purpose of this article is to provide a checklist to discuss OBIEE deployment with your systems administrators. The information in this article is time sensitive, and updated as I discover new  issues or details. What makes OBIEE different? When Tech Support suggests AIX component upgrades to a stable, locked-down production AIX environment, it is common to get "push back".  "Why is this necessary?  We aren't we seeing issues with other software?"It's a fair question that I have often struggled to answer; here are the talking points: OBIEE is memory intensive.  It is the entire purpose of the software to trade memory for repetitive, more expensive database requests across a network. OBIEE is implemented in C++ and is very dependent on the C++ runtime to behave correctly. OBIEE is aggressively thread efficient;  if atomic operations on a particular architecture do not work correctly, the software crashes. OBIEE dynamically loads third-party database client libraries directly into the nqsserver process.  If the library is not thread-safe, or corrupts process memory the OBIEE crash happens in an unrelated part of the code.  These are extremely difficult bugs to find. OBIEE software uses 99% common source across multiple platforms:  Windows, Linux, AIX, Solaris and HPUX.  If a crash happens on only one platform, we begin to suspect other factors.  load intensity, system differences, configuration choices, hardware failures.  It is rare to have a single product require so many diverse technical skills.   My role in support is to understand system configurations, performance issues, and crashes.   An analyst trained in Business Analytics can't be expected to know AIX internals in the depth required to make configuration choices.  Here are some guidelines. AIX C++ Runtime must be at  version 11.1.0.4$ lslpp -L | grep xlC.aixobiee software will crash if xlC.aix.rte is downlevel;  this is not a "try it" suggestion.Nov 2011 11.1.0.4 version  is appropriate for all AIX versions ( 5, 6, 7 )Download from here:https://www-304.ibm.com/support/docview.wss?uid=swg24031426 No reboot is necessary to install, it can even be installed while applications are using the current version.Restart the apps, and they will pick up the latest version. AIX 5.3 Technology Level 12 is required when running on Power5,6,7 processorsAIX 6.1 was introduced with the newer Power chips, and we have seen no issues with 6.1 or 7.1 versions.Customers with an unstable deployment, dozens of unexplained crashes, became stable after the upgrade.If your AIX system is 5.3, the minimum TL level should be at or higher than this:$ oslevel -s  5300-12-03-1107IBM typically supports only the two latest versions of AIX ( 6.1 and 7.1, for example).  AIX 5.3 is still supported and popular running in an LPAR. obiee userid limits$ ulimit -Ha  ( hard limits )$ ulimit -a   ( default limits )core file size (blocks)     unlimiteddata seg size (kbytes)      unlimitedfile size (blocks)          unlimitedmax memory size (kbytes)    unlimitedopen files                  10240 cpu time (seconds)          unlimitedvirtual memory (kbytes)     unlimitedIt is best to establish the values in /etc/security/limitsroot user is needed to observe and modify this file.If you modify a limit, you will need to relog in to change it again.  For example,$ ulimit -c 0$ ulimit -c 2097151cannot modify limit: Operation not permitted$ ulimit -c unlimited$ ulimit -c0There are only two meaningful values for ulimit -c ; zero or unlimited.Anything else is likely to produce a truncated core file that cannot be analyzed. Deploy 32-bit or 64-bit ?Early versions of OBIEE offered 32-bit or 64-bit choice to AIX customers.The 32-bit choice was needed if a database vendor did not supply a 64-bit client library.That's no longer an issue and beginning with OBIEE 11, 32-bit code is no longer shipped.A common error that leads to "out of memory" conditions to to accept the 32-bit memory configuration choices on 64-bit deployments.  The significant configuration choices are: Maximum process data (heap) size is in an AIX environment variableLDR_CNTRL=IGNOREUNLOAD@LOADPUBLIC@PREREAD_SHLIB@MAXDATA=0x... Two thread stack sizes are made in obiee NQSConfig.INI[ SERVER ]SERVER_THREAD_STACK_SIZE = 0;DB_GATEWAY_THREAD_STACK_SIZE = 0; Sort memory in NQSConfig.INI[ GENERAL ]SORT_MEMORY_SIZE = 4 MB ;SORT_BUFFER_INCREMENT_SIZE = 256 KB ; Choosing a value for MAXDATA:0x080000000  2GB Default maximum 32-bit heap size ( 8 with 7 zeros )0x100000000  4GB 64-bit breaking even with 32-bit ( 1 with 8 zeros )0x200000000  8GB 64-bit double 32-bit max0x400000000 16GB 64-bit safetyUsing 2GB heap size for a 64-bit process will almost certainly lead to an out-of-memory situation.Registers are twice as big ... consume twice as much memory in the heap.Upgrading to a 4GB heap for a 64-bit process is just "breaking even" with 32-bit.A 32-bit process is constrained by the 32-bit virtual addressing limits.  Heap memory is used for dynamic requirements of obiee software, thread stacks for each of the configured threads, and sometimes for shared libraries. 64-bit processes are not constrained in this way;  extra heap space can be configured for safety against a query that might create a sudden requirement for excessive storage.  If the storage is not available, this query might crash the whole server and disrupt existing users.There is no performance penalty on AIX for configuring more memory than required;  extra memory can be configured for safety.  If there are no other considerations, start with 8GB.Choosing a value for Thread Stack size:zero is the value documented to select an appropriate default for thread stack size.  My preference is to change this to an absolute value, even if you intend to use the documented default;  it provides better documentation and removes the "surprise" factor.There are two thread types that can be configured. GATEWAY is used by a thread pool to call a database client library to establish a DB connection.The default size is 256KB;  many customers raise this to 512KB ( no performance penalty for over-configuring ). This value must be set to 1 MB if Teradata connections are used. SERVER threads are used to run queries.  OBIEE uses recursive algorithms during the analysis of query structures which can consume significant thread stack storage.  It's difficult to provide guidance on a value that depends on data and complexity.  The general notion is to provide more space than you think you need,  "double down" and increase the value if you run out, otherwise inspect the query to understand why it is too complex for the thread stack.  There are protections built into the software to abort a single user query that is too complex, but the algorithms don't cover all situations.256 KB  The default 32-bit stack size.  Many customers increased this to 512KB on 32-bit.  A 64-bit server is very likely to crash with this value;  the stack contains mostly register values, which are twice as big.512 KB  The documented 64-bit default.  Some early releases of obiee didn't set this correctly, resulting in 256KB stacks.1 MB  The recommended 64-bit setting.  If your system only ever uses 512KB of stack space, there is no performance penalty for using 1MB stack size.2 MB  Many large customers use this value for safety.  No performance penalty.nqscheduler does not use the NQSConfig.INI file to set thread stack size.If this process crashes because the thread stack is too small, use this to set 2MB:export OBI_BACKGROUND_STACK_SIZE=2048 Shared libraries are not (shared) When application libraries are loaded at run-time, AIX makes a decision on whether to load the libraries in a "public" memory segment.  If the filesystem library permissions do not have the "Read-Other" permission bit, AIX loads the library into private process memory with two significant side-effects:* The libraries reduce the heap storage available.      Might be significant in 32-bit processes;  irrelevant in 64-bit processes.* Library code is loaded into multiple real pages for execution;  one copy for each process.Multiple execution images is a significant issue for both 32- and 64-bit processes.The "real memory pages" saved by using public memory segments is a minor concern.  Today's machines typically have plenty of real memory.The real problem with private copies of libraries is that they consume processor cache blocks, which are limited.   The same library instructions executing in different real pages will cause memory delays as the i-cache ( instruction cache 128KB blocks) are refreshed from real memory.   Performance loss because instructions are delayed is something that is difficult to measure without access to low-level cache fault data.   The machine just appears to be running slowly for no observable reason.This is an easy problem to detect, and an easy problem to correct.Detection:  "genld -l" AIX command produces a list of the libraries used by each process and the AIX memory address where they are loaded.32-bit public segment is 13 ( "dxxxxxxx" ).   private segments are 2-a.64-bit public segment is 9 ( "9xxxxxxxxxxxxxxx") ; private segment is 8.genld -l | grep -v ' d| 9' | sort +2provides a list of privately loaded libraries. Repair: chmod o+r <libname>AIX shared libraries will have a suffix of ".so" or ".a".Another technique is to change all libraries in a selected directory to repair those that might not be currently loaded.   The usual directories that need repair are obiee code, httpd code and plugins, database client libraries and java.chmod o+r /shr/dir/*.a /shr/dir/*.so Configure your system for diagnosticsProduction systems shouldn't crash, and yet bad things happen to good software.If obiee software crashes and produces a core, you should configure your system for reliable transfer of the failing conditions to Oracle Tech Support.  Here's what we need to be able to diagnose a core file from your system.* fullcore enabled. chdev -lsys0 -a fullcore=true* core naming enabled. chcore -n on -d* ulimit must not truncate core. see item 3.* pstack.sh is used to capture core documentation.* obidoc is used to capture current AIX configuration.* snapcore  AIX utility captures core and libraries. Use the proper syntax. $ snapcore -r corename executable-fullpath   /tmp/snapcore will contain the .pax.Z output file.  It is compressed.* If cores are directed to a common directory, ensure obiee userid can write to the directory.  ( chcore -p /cores -d ; chmod 777 /cores )The filesystem must have sufficient space to hold a crashing obiee application.Use:  df -k  Check the "Free" column ( not "% Used" )  8388608 is 8GB. Disable Oracle Client Library signal handlingThe Oracle DB Client Library is frequently distributed with the sqlplus development kit.By default, the library enables a signal handler, which will document a call stack if the application crashes.   The signal handler is not needed, and definitely disruptive to obiee diagnostics.   It needs to be disabled.   sqlnet.ora is typically located at:   $ORACLE_HOME/network/admin/sqlnet.oraAdd this line at the top of the file:   DIAG_SIGHANDLER_ENABLED=FALSE Disable async query in the RPD connection pool.This might be an obiee 10.1.3.4 issue only ( still checking  )."async query" must be disabled in the connection pools.It was designed to enable query cancellation to a database, and turned out to have too many edge conditions in normal communication that produced random corruption of data and crashes.  Please ensure it is turned off in the RPD. Check AIX error report (errpt).Errors external to obiee applications can trigger crashes.  $ /bin/errpt -aHardware errors ( firmware, adapters, disks ) should be reported to IBM support.All application core files are recorded by AIX;  the most recent ones are listed first. Reserved for something important to say.

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  • MVVM Light V4 preview (BL0014) release notes

    - by Laurent Bugnion
    I just pushed to Codeplex an update to the MVVM Light source code. This is an early preview containing some of the features that I want to release later under the version 4. If you find these features useful for your project, please download the source code and build the assemblies. I will appreciate greatly any issue report. This version is labeled “V4.0.0.0/BL0014”. The “BL” string is an old habit that we used in my days at Siemens Building Technologies, called a “base level”. Somehow I like this way of incrementing the “base level” independently of any other consideration (such as alpha, beta, CTP, RTM etc) and continue to use it to tag my software versions. In Microsoft parlance, you could say that this is an early CTP of MVVM Light V4. Caveat The code is unit tested, but as we all know this does not mean that there are no bugs This code has not yet been used in production. Again, your help in testing this is greatly appreciated, so please report all bugs to me! What’s new? The following features have been implemented: Misc Various “maintenance work”. All WPF assemblies (that is .NET35 and .NET4) now allow partially trusted callers. It means that you can use them in am XBAP in partial trust mode. Testing Various test updates Added Windows Phone 7 unit tests Note: For Windows Phone 7, due to an issue in the unit test framework, not all tests can be executed. I had to isolate those tests for the moment. The error was reported to Microsoft. ViewModelBase The constructor is now public to allow serialization (especially useful on the phone to tombstone the state). ViewModelBase.MessengerInstance now returns Messenger.Default unless it is set explicitly. Previously, MessengerInstance was returning null, which was complicating the code. Two new ways to raise the PropertyChanged event have been added. See below for details. Messenger Updated the IMessenger interface with all public members from the Messenger class. Previously some members were missing. A new Unregister method is now available, allowing to unregister a recipient for a given token. RelayCommand RaiseCanExecuteChanged now acts the same in Windows Presentation Foundation than in Silverlight. In previous versions, I was relying on the CommandManager to raise the CanExecuteChanged event in WPF. However, it was found to be too unreliable, and a more direct way of raising the event was found preferable. See below for details. Raising the PropertyChanged event A very much requested update is now included: the ability to raise the PropertyChanged event in a viewmodel without using “magic strings”. Personally, I don’t see strings as a major issue, thanks to two features of the MVVM Light Toolkit: In the DEBUG configuration, every time that the RaisePropertyChanged method is called, the name of the property is checked against all existing properties of the viewmodel. Should the property name be misspelled (because of a typo or refactoring), an exception is thrown, notifying the developer that something is wrong. To avoid impacting the performance, this check is only made in DEBUG configuration, but that should be enough to warn the developers in case they miss a rename. The property name is defined as a public constant in the “mvvminpc” code snippet. This allows checking the property name from another class (for example if the PropertyChanged event is handled in the view). It also allows changing the property name in one place only. However, these two safeguards didn’t satisfy some of the users, who requested another way to raise the PropertyChanged event. In V4, you can now do the following: Using lambdas private int _myProperty; public int MyProperty { get { return _myProperty; } set { if (_myProperty == value) { return; } _myProperty = value; RaisePropertyChanged(() => MyProperty); } } This raises the property changed event using a lambda expression instead of the property name. Light reflection is used to get the name. This supports Intellisense and can easily be refactored. You can also broadcast a PropertyChangedMessage using the Messenger.Default instance with: private int _myProperty; public int MyProperty { get { return _myProperty; } set { if (_myProperty == value) { return; } var oldValue = _myProperty; _myProperty = value; RaisePropertyChanged(() => MyProperty, oldValue, value, true); } } Using no arguments When the RaisePropertyChanged method is called within a setter, you can also omit the property name altogether. This will fail if executed outside of the setter however. Also, to avoid confusion, there is no way to broadcast the PropertyChangedMessage using this syntax. private int _myProperty; public int MyProperty { get { return _myProperty; } set { if (_myProperty == value) { return; } _myProperty = value; RaisePropertyChanged(); } } The old way Of course the “old” way is still supported, without broadcast: public const string MyPropertyName = "MyProperty"; private int _myProperty; public int MyProperty { get { return _myProperty; } set { if (_myProperty == value) { return; } _myProperty = value; RaisePropertyChanged(MyPropertyName); } } And with broadcast: public const string MyPropertyName = "MyProperty"; private int _myProperty; public int MyProperty { get { return _myProperty; } set { if (_myProperty == value) { return; } var oldValue = _myProperty; _myProperty = value; RaisePropertyChanged(MyPropertyName, oldValue, value, true); } } Performance considerations It is notorious that using reflection takes more time than using a string constant to get the property name. However, after measuring for all platforms, I found the differences to be very small. I will measure more and submit the results to the community for evaluation, because some of the results are actually surprising (for example, using the Messenger to broadcast a PropertyChangedMessage does not significantly increase the time taken to raise the PropertyChanged event and update the bindings). For now, I submit this code to you, and would be delighted to hear about your own results. Raising the CanExecuteChanged event manually In WPF, until now, the CanExecuteChanged event for a RelayCommand was raised automatically. Or rather, it was attempted to be raised, using a feature that is only available in WPF called the CommandManager. This class monitors the UI and when something occurs, it queries the state of the CanExecute delegate for all the commands. However, this proved unreliable for the purpose of MVVM: Since very often the value of the CanExecute delegate changes according to non-UI events (for example something changing in the viewmodel or in the model), raising the CanExecuteChanged event manually is necessary. In Silverlight, the CommandManager does not exist, so we had to raise the event manually from the start. This proved more reliable, and I now changed the WPF implementation of the RaiseCanExecuteChanged method to be the exact same in WPF than in Silverlight. For instance, if a command must be enabled when a string property is set to a value other than null or empty string, you can do: public MainViewModel() { MyTestCommand = new RelayCommand( () => DoSomething(), () => !string.IsNullOrEmpty(MyProperty)); } public const string MyPropertyName = "MyProperty"; private string _myProperty = string.Empty; public string MyProperty { get { return _myProperty; } set { if (_myProperty == value) { return; } _myProperty = value; RaisePropertyChanged(MyPropertyName); MyTestCommand.RaiseCanExecuteChanged(); } } Logo update I made a minor change to the logo: Some people found the lack of the word “light” (as in MVVM Light Toolkit) confusing. I thought it was cool, because the feather suggests the idea of lightness, however I can see the point. So I added the word “light” to the logo. Things should be quite clear now. What’s next? This is only the first of a series of releases that will bring MVVM Light to V4. In the next weeks, I will continue to add some very requested features and correct some issues in the code. I will probably continue this fashion of releasing the changes to the public as source code through Codeplex. I would be very interested to hear what you think of that, and to get feedback about the changes. Cheers, Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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  • Anyone know about AppDynamics? Does Microsoft already have something similiar? Event viewer? Im confused

    - by punkouter
    We have a big collection of java (80%) and .Net (20%) apps.. And the people in charge want a way to monitor the applications somehow. So they told me they are interested in AppDynamics? I have spent a bit looking into it but I still don't get it. Can someone tell me what its about ? From my understanding it seems like you would someone inject the AppDynamics API in your code to tell about differnt events that occur? So sounds like Event Viewer ? I am on the .NET side of this and seems to me we can just write data to a log and report off of that data.. I don't get what the additional complexity of using'AppDynamics' does. Maybe it is overkill ??

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  • jquery livequery event triggered on EVERYTHING, not just selected element.

    - by phazei
    I am attempting to use livequery. I unfortunately am stuck using jquery 1.2.6. This is my code: $(document).ready(function() { $('a.sort').livequery('click', function(event) { alert('hello'); }); }); If I click ANYWHERE in the document, I get the alert 'hello'. What exactly is wrong there? Is it some bug with jQ1.2.6 and livequery 1.1.1? This same question was asked here but the question wasn't clear, and the answer didn't help.

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  • Using Xlib via JNA to move a window

    - by rob
    I'm using JNA to manipulate application windows on Linux by sending Xlib messages but can't seem to move a window. My original implementation executed wmctrl on the shell to move the windows and that successfully moved the windows. Unfortunately, there's a noticeable amount of overhead associated with calling shell programs from Java, so now I'm trying to make direct API calls using JNA. I'm using the X11 example available from the JNA website and can successfully do a few tricks, such as enumerating the window IDs and reading window properties, so I know JNA+Xlib is at least partially working. First I tried moving the windows directly using XMoveWindow() but the window manager was apparently blocking those calls. I ran across a thread that suggested I needed to send a client message using XSendMessage(), so I've done that below, but apparently XSendMessage() is failing because the window doesn't move and I get a return value of 0. I'm guessing I omitted something obvious, but can't quite figure it out. Any suggestions? Note that, for the purposes of this example, the main method has a window ID hard-coded. This is the window ID of the window I'm trying to move (obtained using wmctrl -l on the console). import com.sun.jna.NativeLong; import com.sun.jna.Pointer; import com.sun.jna.examples.unix.X11; import com.sun.jna.examples.unix.X11.Atom; import com.sun.jna.examples.unix.X11.AtomByReference; import com.sun.jna.examples.unix.X11.Display; import com.sun.jna.examples.unix.X11.Window; import com.sun.jna.examples.unix.X11.WindowByReference; import com.sun.jna.examples.unix.X11.XEvent; import com.sun.jna.examples.unix.X11.XTextProperty; import com.sun.jna.examples.unix.X11.XWindowAttributes; import com.sun.jna.ptr.IntByReference; import com.sun.jna.ptr.NativeLongByReference; import com.sun.jna.ptr.PointerByReference; private static final int FALSE = 0; /** C-style boolean "false" */ private static final int TRUE = 1; /** C-style boolean "true" */ public static void main(String[] args) { setWindowPos(new Window(0x01300007), 100, 100, 600, 400); // update the Window constructor with the appropriate ID given by wmctrl -l } public static boolean setWindowPos(Window window, int x, int y, int w, int h) { final X11 x11 = X11.INSTANCE; Display display = x11.XOpenDisplay(null); NativeLong mask = new NativeLong(X11.SubstructureRedirectMask | X11.SubstructureNotifyMask | X11.ResizeRedirectMask); XEvent event = new XEvent(); String msg = "_NET_MOVERESIZE_WINDOW"; //$NON-NLS-1$ long grflags = 0l; // use the default gravity of the window if (x != -1) grflags |= (1 << 8); if (y != -1) grflags |= (1 << 9); if (w != -1) grflags |= (1 << 10); if (h != -1) grflags |= (1 << 11); event.xclient.type = X11.ClientMessage; event.xclient.serial = new NativeLong(0l); event.xclient.send_event = TRUE; event.xclient.message_type = x11.XInternAtom(display, msg, false); event.xclient.window = window; event.xclient.format = 32; event.xclient.data.l[0] = new NativeLong(grflags); // gravity flags event.xclient.data.l[1] = new NativeLong(x); event.xclient.data.l[2] = new NativeLong(y); event.xclient.data.l[3] = new NativeLong(w); event.xclient.data.l[4] = new NativeLong(h); int status = x11.XSendEvent(display, x11.XDefaultRootWindow(display), FALSE, mask, event); x11.XFlush(display); // need to XFlush if we're not reading X events if (status == 0) { // 0 indicates XSendEvent failed logger.error("setWindowPos: XSendEvent failed (" + msg + ")"); //$NON-NLS-1$ return false; } return true; }

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  • Do WPF ComboBox SelectedIndex and SelectedValue have different behavior on SelectionChanged event?

    - by Junior Mayhé
    Hello guys I got this cbxJobPosition_SelectionChanged firing as expected. The problem is when a external method tries to set cbxJobPosition. cbxJobPosition is databinded with a list of objects of type JobPosition: JobPositionID: 1, JobPositionName: Manager JobPositionID: 2, JobPositionName: Employee JobPositionID: 3, JobPositionName: Third party Here's the XAML: <ComboBox Cursor="Hand" DataContext="{Binding}" ItemsSource="{Binding}" FontSize="13" Name="cbxJobPosition" SelectedValuePath="JobPositionID" DisplayMemberPath="JobPositionName" SelectedIndex="0" Width="233" Height="23" SelectionChanged="cbxJobPosition_SelectionChanged" /> On UserControl_Loaded method, it reads from database the list of jobs and try to set the specific job position "Third party": //calls cbxJobPosition_SelectionChanged and passes the correct SelectedValue within cbxJobPosition.SelectedIndex = 3; //calls cbxJobPosition_SelectionChanged and but won't pass the correct SelectedValue within cbxJobPosition.SelectedValue = "3"; As you can notice, when the processing is automatically redirected to cbxJobPosition_SelectionChanged, the SelectedValue attribute will have different values for each statement above when you're debugging within cbxJobPosition_SelectionChanged event. Does anyone know if this difference is expected, am I missing something or it could be a bug?

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  • How to bind Checked event for radio button in WPF?

    - by nullDev
    I am using the following markup in WPF: <StackPanel.Triggers> <EventTrigger RoutedEvent="RadioButton.Checked" SourceName="xmlRadioButton"> <EventTrigger.Actions> <BeginStoryboard Storyboard="{StaticResource ShowXmlPanel}"/> </EventTrigger.Actions> </EventTrigger> <EventTrigger RoutedEvent="RadioButton.Checked" SourceName="adiRadioButton"> <EventTrigger.Actions> <BeginStoryboard Storyboard="{StaticResource ShowAdiPanel}"/> </EventTrigger.Actions> </EventTrigger> </StackPanel.Triggers> Though this works fine when I run the code, I get the following error in the designer window of VS 2008: Value 'RadioButton.Checked' cannot be assigned to property 'RoutedEvent'. Invalid event name. Any idea why, and how can I fix this?

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  • Android: How to create an onclick event for a SimpleCursorAdapter?

    - by user117701
    I have this code: db=(new DatabaseHelper(this)).getWritableDatabase(); constantsCursor=db.rawQuery("SELECT _ID, title, subtitle, image "+ "FROM news ORDER BY title", null); ListAdapter adapter=new SimpleCursorAdapter(this, R.layout.row, constantsCursor, new String[] {"title", "subtitle", "image"}, new int[] {R.id.value, R.id.title, R.id.icon}); setListAdapter(adapter); registerForContextMenu(getListView()); Which displays a list of titles. I dont however for the life of me know how to create a click event so that i can call another view when i click an item from that list. Anyone?

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  • using Unity Android In a sub view and add style and actionbar

    - by aeroxr1
    I exported a simple animation from Unity3D (version 4.5) in android project. With eclipse I modified the manifest and added another activity. In this activity I put a button that it makes start the animation,and this is the result. The action bar appear in the main activity but it doesn't in the unity's activity :( This is the unity's activity's code : package com.rabidgremlin.tut.redcube; import android.app.NativeActivity; import android.content.res.Configuration; import android.graphics.PixelFormat; import android.os.Bundle; import android.view.KeyEvent; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.view.WindowManager; import com.unity3d.player.UnityPlayer; public class UnityPlayerNativeActivity extends NativeActivity { protected UnityPlayer mUnityPlayer; // don't change the name of this variable; referenced from native code // Setup activity layout @Override protected void onCreate (Bundle savedInstanceState) { //requestWindowFeature(Window.FEATURE_NO_TITLE); super.onCreate(savedInstanceState); getWindow().takeSurface(null); //setTheme(android.R.style.Theme_NoTitleBar_Fullscreen); getWindow().setFormat(PixelFormat.RGB_565); mUnityPlayer = new UnityPlayer(this); /*if (mUnityPlayer.getSettings ().getBoolean ("hide_status_bar", true)) getWindow ().setFlags (WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); */ setContentView(mUnityPlayer); mUnityPlayer.requestFocus(); } // Quit Unity @Override protected void onDestroy () { mUnityPlayer.quit(); super.onDestroy(); } // Pause Unity @Override protected void onPause() { super.onPause(); mUnityPlayer.pause(); } // eliminiamo questa onResume() e proviamo a modificare la onResume() // Resume Unity @Override protected void onResume() { super.onResume(); mUnityPlayer.resume(); } // inseriamo qualche modifica qui // This ensures the layout will be correct. @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); mUnityPlayer.configurationChanged(newConfig); } // Notify Unity of the focus change. @Override public void onWindowFocusChanged(boolean hasFocus) { super.onWindowFocusChanged(hasFocus); mUnityPlayer.windowFocusChanged(hasFocus); } // For some reason the multiple keyevent type is not supported by the ndk. // Force event injection by overriding dispatchKeyEvent(). @Override public boolean dispatchKeyEvent(KeyEvent event) { if (event.getAction() == KeyEvent.ACTION_MULTIPLE) return mUnityPlayer.injectEvent(event); return super.dispatchKeyEvent(event); } // Pass any events not handled by (unfocused) views straight to UnityPlayer @Override public boolean onKeyUp(int keyCode, KeyEvent event) { return mUnityPlayer.injectEvent(event); } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { return mUnityPlayer.injectEvent(event); } @Override public boolean onTouchEvent(MotionEvent event) { return mUnityPlayer.injectEvent(event); } /*API12*/ public boolean onGenericMotionEvent(MotionEvent event) { return mUnityPlayer.injectEvent(event); } } How can I add the action bar and the style of the first activity to unity's animation activity ?

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  • reinventing the wheels: Node.JS/Event-driven programming v.s. Functional Programming?

    - by ivanTheTerrible
    Now there's all the hype lately about Node.JS, an event driven framework using Javascript callbacks. To my limited understanding, its primary advantage seems to be that you don't have to wait step by step sequentially (for example, you can fetch the SQL results, while calling other functions too). So my question is: how is this different, or better than just functional languages, like CL, Haskell, Clojure etc? If not better, then why don't people just do functional languages then (instead of reinventing the wheel with Javascript)? Please note that I have none experience in either Node.JS nor functional programming. So some basic explanation can be helpful.

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  • How to manage a MotionEvent going from one View to another?

    - by Darren
    I have a SurfaceView that takes up part of the screen, and some buttons along the bottom. When a button is pressed and the user drags, I want to be able to drag a picture (based on the button) onto the SurfaceView and have it drawn there. I want to be able to use clickListeners and the like, and not just have a giant SurfaceView with me writing code to detect where the user pressed and if it's a button, etc. I have somewhat of a solution, but it seems a bit of a hack to me. What is the best way to accomplish this using the framework intelligently? Part of my XML: <RelativeLayout android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@drawable/background"> <!-- Place buttons along the bottom --> <RelativeLayout android:id="@+id/bottom_bar" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="40dip" android:layout_alignParentBottom="true" android:background="@null"> <ImageButton android:id="@+id/btn_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:background="@null" android:src="@drawable/btn_1"> </ImageButton> <!-- More buttons here... --> </RelativeLayout> <!-- Place the SurfaceView in a frame so we can stack on top of it --> <FrameLayout android:layout_width="fill_parent" android:layout_height="0px" android:layout_weight="1" android:layout_above="@id/bottom_bar"> <com.project.question.MySurfaceView android:id="@+id/my_view" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </FrameLayout> And the relevant Java code in MySurfaceView, which extends SurfaceView. mTouchX and Y are used in the onDraw method to draw the image: @Override public boolean onTouchEvent(MotionEvent event){ mTouchX = (int) event.getX(); mTouchY = (int) event.getY(); return true; } public void onButtonTouchEvent(MotionEvent event){ event.setLocation(event.getX(), event.getY() + mScreenHeight); onTouchEvent(event); } Finally, the activity: @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.my_surface); mView = (MySurfaceView) findViewById(R.id.my_view); mSurfaceHeight = mView.getHeight(); mBtn = (ImageButton) findViewById(R.id.btn_1); mBtn.setOnTouchListener(mTouchListener); } OnTouchListener mTouchListener = new OnTouchListener() { public boolean onTouch(View v, MotionEvent event) { int [] location = new int[2]; v.getLocationOnScreen(location); event.setLocation(event.getX() + location[0], event.getY()); mView.onButtonTouchEvent(event); return true; } }; Strangely, one has to add to the x-coordinate in the activity, then add to the y coordinate in the View. Otherwise, it doesn't show up in the correct position. If you add nothing, something drawn using mTouchX and mTouchY will show up in the upper left corner of the SurfaceView. Any direction would be greatly appreciated. If I'm going about this completely the wrong way, that would be good information too.

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  • How to add event log category in Windows Server 2008?

    - by Jay
    I have created a service plan to run on Windows server 2008. When I test the service in my Windows XP, the event log category can be created properly. However, It doesn't work on server 2008. I run the service as administrator account already. private EventLog __eventLog; if (!EventLog.SourceExists("MyEventLogCat")) EventLog.CreateEventSource("MyEventLogCat", "MyEventLogCat"); __eventLog = new EventLog(); __eventLog.Source = "MyEventLogCat"; __eventLog.Log = "MyEventLogCat"; Thanks.

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  • How to stop a WPF binding from ignoring the PropertyChanged event that it caused?

    - by Jacob Stanley
    I have a TextBox bound to a ViewModel's Text property with the following setup: Xaml <TextBox Text="{Binding Text}"/> C# public class ViewModel : INotifyPropertyChanged { public string Text { get { return m_Text; } set { if (String.Equals(m_Text, value)) { return; } m_Text = value.ToLower(); RaisePropertyChanged("Text"); } } // Snip } When I type some stuff in to the TextBox it successfully sets the Text property on the ViewModel. The problem is that WPF ignores the property changed event that is raised by it's own update. This results in the user not seeing the text they typed converted to lowercase. How can I change this behaviour so that the TextBox updates with lowercase text? Note: this is just an example I have used to illustrate the problem of WPF ignoring events. I'm not really interested in converting strings to lowercase or any issues with String.Equals(string, string).

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  • how to bind the click event of a button and the selecteditemchanged of a listbox to a viewmodel in m

    - by Michel
    Hi, i'm just starting with the mvvm model in Silverlight. In step 1 i got a listbox bound to my viewmodel, but now i want to propagate a click in a button and a selecteditemchanged of the listbox back to the viewmodel. I guess i have to bind the click event of the button and the selecteditemchanged of the listbox to 2 methods in my viewmodel somehow? For the selecteditemchanged of the listbox i think there must also be a 'return call' possible when the viewmodel tries to set the selecteditem to another value? i come from a asp.net (mvc) background, but can't figure out how to do it in silverlight.

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  • Any ideas on how to implement a 'touchMoveOver' event in Javascript?

    - by gargantaun
    I'm faffing around with SVG, specifically for web content aimed at iPad users. I've created a little dial type thingy that I'm calling a "cheese board" that I'd like to use as an interface element. http://appliedworks.co.uk/files/times/SVGTests/raphael.html Clicking on a piece of cheese (to keep the analogy going) will do "something". That bit's easy. However, I'd like the user to be able to drag their finger around the 'cheese board', firing a new event (touchesMovedOver?) every time they their finger moves over a new piece of cheese. But I can't figure out how to do it since there's no 'mouseOver' equivalent for touch interfaces. If the whole thing was made of squares, I could have created some sort of 'rectContainsPoint' method to be called for every 'touchesMoved', but that approach wouldn't work here. If anyone has any idea about how something like this could be achieved, I'd love to hear it.

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  • Why is e.Item.DataItem null on ItemDataBound event when binding an asp:net Repeater to a Collection?

    - by Clean
    Hi, I'm trying to bind a collection implementing the ICollection, IEnumerable and IList interface to an asp.net repeater. The Collection is named CustomCollection. So I'm setting the datasource of the repeater to the collection, as follows: rptRepeater.DataSource = customCollection; rptRepeater.Databind(); Then, on the ItemDataBound event, I'm trying to access the DataItem object, as follow: void rptRepeater_ItemDataBound(object sender, RepeaterItemEventArgs e){ object obj = e.Item.DataItem; // DataItem is null for some reason } For some reason the e.Item.DataItem object is null. Do anyone know why this is, and/or what I could do to get hold of the object in the collection that is to be databound to the repeater? Thanx!

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  • How to change onmouseover event to onclick instead in javascript?

    - by KT
    I am using this plugin in wordpress http://www.iwebix.de/front-slider-wordpress-plugin-demo/ As you can see in the demo above, the left and right arrow buttons are the controls for scrolling the thumbnails and the event is onmouseover and onmouseout. I don't know how to change this to onclick instead so that the thumbnails will scroll left and right only when the buttons are clicked. Any help or ideas on how to do this? Thanks! Here is the script. http://www.iwebix.de/wp-content/plugins/front-slider/scripts/slider.js

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  • How to stop toggle event from being fired multiple times on mouseenter/mouseleave?

    - by Clean
    Hi, I'm using jQuery to toggle the visibility of a using the jQuery toggle method. The toggle is fired on the mouseenter and mouseleave event, thus creating the effect of the div to fold out on mouseenter and fold in on mouseleave. Problem is, if the user drags the mouse over the a few times and then leaves the , the div will toggle in and out several times. This can happen if the user accidentally moves around the mouse pointer in the are. Do anyone have any idea on how I can avoid this behavior? Thanx!

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