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  • Where can I find a control similar to the Firefox Rich List Box for use in my application?

    - by bsruth
    I'm trying to implement a control similar to Firefox's Rich List Box: However, I can only find the XUL implementation of this control, and I don't want to have to include a XUL processing engine in my application just to get a cool looking listbox. I've been trying to implement one on my own by customizing MFC's CListBox control, but am starting to realize it may take more time than I had intended. Before continuing to implement this control from scratch, I was wondering if anyone knew of a similar control that already exists, either commercial or open source. The main functionality I would like to have is: Small display for non selected items that expands when selected. Ability to add arbitrary controls to the expanded view. Preferably native code, but can probably use managed controls via native/managed interop with out too much extra work. Any help would be appreciated, I don't want to have to reinvent the wheel if I don't have to.

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  • Do I really have to call Focus in OnMouseDown of my custom Control?

    - by Thomas
    I'm implementing a custom control that inherits from Control. I want it to be focusable (it's a kind of list box). In the constructor, I do SetStyle(ControlStyles.Selectable, true); I can now use Tab to navigate to the control. However, when the control receives a mouse click, it does not automatically claim focus. I can work around this, of course: protected override void OnMouseDown(MouseEventArgs e) { Focus(); base.OnMouseDown(e); } But this feels like a kludge that should not be necessary. Is this really the way to go? Or is there some way to tell Control to claim focus automatically when it receives a mouse click?

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  • What's the difference between Path and Polygon control? + issues when designing custom drawing user

    - by tomo
    I'm starting to design a custom control with rather complex drawing. It will be a kind of chart (a kind of radar chart). It will be composed of a few axises with labels, line-regions (like spider-network) and filled shapes. The main question is what's the difference between using Path control and Polygon control? What's better to use here? The goal is to prepare control with minimal amount of c# and try to do as much as possible in xaml / binding. The next important requirement is that control should resize to parent containers' width - if possible without any long recalulations in c#.

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  • User control event or method override where custom properties are valid?

    - by Curtis White
    I have an ASP.NET user control that is used in another use control. The parent user control uses data-binding to bind to a custom property of the child user control. What method can I override or page event where I am ensured that the property state is set? I think in a page it is PageLoaded versus the Page_Load override? I am looking for this in the user control because my property is always null even though it is set. Thanks.

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  • Multithreading: Communication from Parent thread to child thread

    - by Dennis Nowland
    I have a List of threads normally 3 threads each of the threads reference a webbrowser control that communicates with the parent control to populate a datagridview. What I need to do is when the user clicks the button in a datagridviewButtonCell corresponding data will be sent back to the webbrowser control within the child thread that originally communicated with the main thread. but when I try to do this I receive the following error message 'COM object that has been separated from its underlying RCW cannot be used.' my problem is that I can not figure out how to reference the relevant webbrowser control. I would appreciate any help that anyone can give me. The language used is c# winforms .Net 4.0 targeted Code sample: The following code is executed when user click on the Start button in the main thread private void StartSubmit(object idx) { /* method used by the new thread to initialise a 'myBrowser' inherited from the webbrowser control each submitters object is an a custom Control called 'myBrowser' which holds detail about the function of the object eg: */ //index: is an integer value which represents the threads id int index = (int)idx; //submitters[index] is an instance of the 'myBrowser' control submitters[index] = new myBrowser(); //threads integer id submitters[index]._ThreadNum = index; // naming convention used 'browser' +the thread index submitters[index].Name = "browser" + index; //set list in 'myBrowser' class to hold a copy of the list found in the main thread submitters[index]._dirs = dirLists[index]; // suppress and javascript errors the may occur in the 'myBrowser' control submitters[index].ScriptErrorsSuppressed = true; //execute eventHandler submitters[index].DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(DocumentCompleted); //advance to the next un-opened address in datagridview the navigate the that address //in the 'myBrowser' control. SetNextDir(submitters[index]); } private void btnStart_Click(object sender, EventArgs e) { // used to fill list<string> for use in each thread. fillDirs(); //connections is the list<Thread> holding the thread that have been opened //1 to 10 maximum for (int n = 0; n < (connections.Length); n++) { //initialise new thread to the StartSubmit method passing parameters connections[n] = new Thread(new ParameterizedThreadStart(StartSubmit)); // naming convention used conn + the threadIndex ie: 'conn1' to 'conn10' connections[n].Name = "conn" + n.ToString(); // due to the webbrowser control needing to be ran in the single //apartment state connections[n].SetApartmentState(ApartmentState.STA); //start thread passing the threadIndex connections[n].Start(n); } } Once the 'myBrowser' control is fully loaded I am inserting form data into webforms found in webpages loaded via data enter into rows found in the datagridview. Once a user has entered the relevant details into the different areas in the row the can then clicking a DataGridViewButtonCell that has tha collects the data entered and then has to be send back to the corresponding 'myBrowser' object that is found on a child thread. Thank you

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  • Is it OK to set "Cache-Control: public" when sending “304 Not Modified” for images stored in the dat

    - by Emilien
    After asking a question about sending “304 Not Modified” for images stored in the in the Google App Engine datastore, I now have a question about Cache-Control. My app now sends Last-Modified and Etag, but by default GAE alsto sends Cache-Control: no-cache. According to this page: The “no-cache” directive, according to the RFC, tells the browser that it should revalidate with the server before serving the page from the cache. [...] In practice, IE and Firefox have started treating the no-cache directive as if it instructs the browser not to even cache the page. As I DO want browsers to cache the image, I've added the following line to my code: self.response.headers['Cache-Control'] = "public" According to the same page as before: The “cache-control: public” directive [...] tells the browser and proxies [...] that the page may be cached. This is good for non-sensitive pages, as caching improves performance. The question is if this could be harmful to the application in some way? Would it be best to send Cache-Control: must-revalidate to "force" the browser to revalidate (I suppose that is the behavior that was originally the reason behind sending Cache-Control: no-cache) This directive insists that the browser must revalidate the page against the server before serving it from cache. Note that it implicitly lets the browser cache the page.

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  • Cannot add SourceSafe Database as Visual Studio 2010 source control.

    - by CletusLoomis
    My issue is that I cannot add SourceSafe Database for source control within Visual Studio 2010. Our team was initially using VSS for source control in Visual Studio 2010. During an evaluation of TFS, I switched my source control to TFS. It will be a few weeks before a decision is made on TFS, so I needed to switch my source control back to VSS. However I'm now unable to add a SourceSafe Database in Visual Studio. Steps to Reproduce in Visual Studio 2010: 1) Access the 'Open SourceSafe Database' form via Tools-Options-Source Control-Plug-in Settings--Advanced or via File-Source Control 2) The list of available database is blank so I choose 'Browse'. 3) I browse to the srcsafe.ini file for my VSS database and select it. 4) I'm promted to confirm the Database Name - Click OK. 5) The database does not appear in the 'Open SourceSafe' Database form. The list of available databases is still blank. Note that I can add the database fine outside of Visual Studio using VSS directly. However the databases I add via VSS do not appear in the Visual Studio forms. I'm suspicious that this is related to "down-grading" from TFS to VSS which may not have been heavily tested at MS. Any assistance is appreciated.

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  • (interactive) graph as in graph theory on a web page ?

    - by LB
    Hi, I have to integrate a graph with nodes and edges on a web page. Ideally, i would like to be able to interact with it (like moving the nodes around). Actually, i'm beginning by representing trees, so i would appreciate to be able to collapse subtrees. How can I do that ? I was considering google-visualization api but i wasn't able to find the kind of visualization i'm looking for (org chart doesn't allow to have multiple fathers, if i understood well) I've got no idea of the kind of technology so my tagging may not be really accurate :-). thanks

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  • Linq to SQL Repository ~theory~ - Generic but now uses Linq to Objects?

    - by Matt Tolliday
    The project I am currently working on used Linq to SQL as an ORM data access technology. Its an MVC3 Web app. The problem I faced was primarily due to the inability to mock (for testing) the DataContext which gets autogenerated by the DBML designer. So to solve this issue (after much reading) I refactored the repository system which was in place - single repository with seperate and duplicated access methods for each table which ended up with something like 300 methods only 10 of which were unique - into a single repository with generic methods taking the table and returning more generic types to the upper reaches of the application. My question revolves more around the design I've used to get thus far and the differences I'm noticing in the structure of the app. 1) Having refactored the code from the dark ages which used classic Linq to SQL queries: public Billing GetBilling(int id) { var result = ( from bil in _bicDc.Billings where bil.BillingId == id select bil).SingleOrDefault(); return (result); } it now looks like: public T GetRecordWhere<T>(Expression<Func<T, bool>> predicate) where T : class { T result; try { result = _dataContext.GetTable<T>().Where(predicate).SingleOrDefault(); } catch (Exception ex) { throw ex; } return result; } and is used by the controller with a query along the lines of: _repository.GetRecordWhere<Billing>(x => x.BillingId == 1); which is fine, and precisely what I wanted to achieve. ...however.... I'm also having to do the following to get precisely the result set i require in the controller class (the highest point of the app in essence)... viewModel.RecentRequests = _model.GetAllRecordsWhere<Billing>(x => x.BillingId == 1) .Where(x => x.BillingId == Convert.ToInt32(BillingType.Submitted)) .OrderByDescending(x => x.DateCreated). Take(5).ToList(); This - as far as my understanding is correct - is now using Linq to Objects rather than the Linq to SQL queries I was previously? Is this okay practise? It feels wrong to me but I dont know why. Probably because the logic of the queries is in the very highest tier of the app, rather than the lowest, but... I defer to you good people for advice. One of the issues I considered was bringing the entire table into memory but I understand that using the Iqeryable return type the where clause is taken to the database and evaluated there. Thus returning only the resultset i require... i may be wrong. And if you've made it this far, well done. Thank you, and if you have any advice it is very much appreciated!!

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  • OutOfMemory during paging

    - by Tony
    Hi I am using ObjectDataSource, ListView, CustomPaging If the total number of rows is too big, I got OutOfMemory exception, it seems that it caused by some array, I don't get it, because total number of rows should never make any array to be filled with elements, the page size do!! This is the logger. ****EXCEPTION # 3 : 4/30/2010 9:43:07 PM System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. --- System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown. at System.Web.UI.WebControls.ListView.CreateChildControls() at System.Web.UI.Control.EnsureChildControls() at System.Web.UI.WebControls.ListView.get_Controls() at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Page.LoadAllState() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace --- at System.Web.UI.Page.HandleError(Exception e) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest() at System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) at System.Web.UI.Page.ProcessRequest(HttpContext context) at ASP.default_aspx.ProcessRequest(HttpContext context) in c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\flickrdemo\15752207\c63ea96c\App_Web__8yxn9sb.0.cs:line 0 at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

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  • Sitecore development. Sitecore.Web.UI.WebControl.GetCacheKey() throws NullReferenceException

    - by user344010
    I just click submit button and got an exception. Unable to debug, because this happens before the submit event handler work. I tried to clear sitecore caches, browser caches and cookies... nothing helps. here the stack trace. [NullReferenceException: Object reference not set to an instance of an object.] Sitecore.Web.UI.WebControl.GetCacheKey() +242 Sitecore.Web.UI.WebControl.Render(HtmlTextWriter output) +61 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +134 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19 System.Web.UI.HtmlControls.HtmlHead.RenderChildren(HtmlTextWriter writer) +17 System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +32 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +134 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19 System.Web.UI.Page.Render(HtmlTextWriter writer) +29 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1266

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  • Are GUID primary keys bad in theory, or just practice?

    - by Yarin
    Whenever I design a database I automatically start with an auto-generating GUID primary key for each of my tables (excepting look-up tables) I know I'll never lose sleep over duplicate keys, merging tables, etc. To me it just makes sense philosophically that any given record should be unique across all domains, and that that uniqueness should be represented in a consistent way from table to table. I realize it will never be the most performant option, but putting performance aside, I'd like to know if there are philosophical arguments against this practice?

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  • Why is my user control not instanciated on a postback?

    - by Antoine
    Hi, I'd like to set the trigger of an UpdatePanel to a user control outside the UpdatePanel on the same page . The user control is added at design time, not at runtime. If I statically declare the trigger, I get an error "A control with ID 'xx' cannot be found for the trigger in UpdatePanel". I tried to add the trigger at runtime in Page_Init or Page_Load, but it fails with the user control being null, although it has ViewState enabled. Has someone an idea on how to solve this? Here is the code of the user control: <%@ Control Language="C#" AutoEventWireup="true" CodeFile="ComponentDropDownControl.ascx.cs" Inherits="ComponentDropDownControl" EnableViewState="true" %> <asp:DropDownList ID="ComponentDropDown" runat="server" DataSourceID="ComponentFile" DataTextField="name" DataValueField="name" OnSelectedIndexChanged="ComponentDropDown_SelectedIndexChanged" AutoPostBack="True" EnableTheming="True"> </asp:DropDownList><asp:XmlDataSource ID="ComponentFile" runat="server" DataFile="~/App_Data/Components.xml" XPath="//component"></asp:XmlDataSource> And here it is in the aspx page: <%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="create.aspx.cs" Inherits="create" Title="Create task" %> <%@ Register Src="ComponentDropDownControl.ascx" TagName="ComponentDropDownControl" TagPrefix="uc1" %> ... <uc1:ComponentDropDownControl ID="CustomComponentDropDown" runat="server" EnableViewState="true" /> In the Page_Load function of the aspx page, the following lines work at first time, but fail on the first PostBack (line 2, CustomComponentDropDown is null). AsyncPostBackTrigger trigger = new AsyncPostBackTrigger(); trigger.ControlID = CustomComponentDropDown.UniqueID.ToString(); UpdatePanel1.Triggers.Add(trigger);

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  • Start the Control Panel item Windows Update with WinExec.

    - by Bill
    Windows Vista Canonical Names The Microsoft website says "In Windows Vista and later, the preferred method of launching a Control Panel item from a command line is to use the Control Panel item's canonical name." According to the Microsoft website this should work: The following example shows how an application can start the Control Panel item Windows Update with WinExec. WinExec("%systemroot%\system32\control.exe /name Microsoft.WindowsUpdate", SW_NORMAL); For Delphi 2010 I tried: var CaptionString: string; Applet: string; Result: integer; ParamString: string; CaptionString := ListviewApplets1.Items.Item[ ListviewApplets1.ItemIndex ].Caption; if CaptionString = 'Folder Options' then { 6DFD7C5C-2451-11d3-A299-00C04F8EF6AF } Applet := 'Microsoft.FolderOptions' else if CaptionString = 'Fonts' then {93412589-74D4-4E4E-AD0E-E0CB621440FD} Applet := 'Microsoft.Fonts' else if CaptionString = 'Windows Update' then { 93412589-74D4-4E4E-AD0E-E0CB621440FD } Applet := 'Microsoft.WindowsUpdate' else if CaptionString = 'Game Controllers' then { 259EF4B1-E6C9-4176-B574-481532C9BCE8 } Applet := 'Microsoft.GameControllers' else if CaptionString = 'Get Programs' then { 15eae92e-f17a-4431-9f28-805e482dafd4 } Applet := 'Microsoft.GetPrograms' //... ParamString := ( SystemFolder + '\control.exe /name ' ) + Applet; WinExec( ParamString, SW_NORMAL); <= This does not execute and when I trapped the error it returned ERROR_FILE_NOT_FOUND. I tried a ExecAndWait( ParamString ) method and it works perfectly with the same ParamString used with WinExec: ParamString := ( SystemFolder + '\control.exe /name ' ) + Applet; ExecAndWait( ParamString ); <= This executes and Runs perfectly The ExecAndWait method I used creates a Windows.CreateProcess... if Windows.CreateProcess( nil, PChar( CommandLine ), nil, nil, False, 0, nil, nil, StartupInfo, ProcessInfo ) then begin try My Question Does WinExec require a different ParamString or am I doing this wrong with WinExec? I did not post the full ExecAndWait method but I can if someone wants to see it...

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  • How to automatically extend the tab control as items are added to it without creating a scroll bar?

    - by MICHELINE
    I am using a WPF user control (tab control) to add tab items dynamically in the simplified code below: .... foreach (string id in ids) { TabControl.Items.Add(CreateTabItem(id)); } private TabItem CreateTabItem(string name) { StackPanel txtBlock = new TextBlock(); txtblock.Text = name; txtBlock.HorizontalAlignment = Horizontalalignment.Center; panel.Children.Add(txtBlock); TabItem item = new TabItem(); item.Header = panel; <SomeControl> control = new <SomeControl>(); item.Content = control; return item; } In the xaml file I specified the following to stack all my tab items to the left column: MinWidth="100" MinHeight="300" TabStripPlacement="Left" How do I make my tab control automatically extending (ie. stretching) its height to show all the tab items as I add them in? For now, I have to manually extend the height of the display window to see all the tab items. Your insights/tips are greatly appreciated. PS: if you know how to make the vertical scroll bar appears (without adding scroll bar to my control) as soon as the tab items exceed the window height, I can settle for that if there are no answers for my original intent.

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  • How do I add events to nested server controls? (ASP.Net)

    - by bert
    I am building a custom master page type control i.e. sort of like a datagrid but should be easier to add custom functionality into it. It's going great but part of the desired functionality is to have a paging control that switches on and off and part of that control would be a textbox that displays the current page number and on TextChanged redirects to the new page of the dataset. The problem I'm having is that technically the textbox which has its event fired is embedded in a control that is embedded in the control you actually put on the page sort of like Page  | Display Control  | Paging Control  | Textbox Buried all the way down there the event is not firing. Worse the postback javascript isn't even being written onto the page (Nothing on the page posts back so far this is the only bit that really needs to). I've been trawling around Google for quite a while now and picked up that I need to implement INamingContainer (done) and I need to add the control into the page's control tree (is Pre_Init too late for that? When's a good time to Add the Control to the page?) then the event should fire, apparently. But I've been unable to find an example of best practice on this there are quite a few near misses where people are having button angst but this isn't a button. So can anyone point me in the direction of getting a control embedded in a control embedded in a control added to a page to behave properly?

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  • A Guided Tour of Complexity

    - by JoshReuben
    I just re-read Complexity – A Guided Tour by Melanie Mitchell , protégé of Douglas Hofstadter ( author of “Gödel, Escher, Bach”) http://www.amazon.com/Complexity-Guided-Tour-Melanie-Mitchell/dp/0199798109/ref=sr_1_1?ie=UTF8&qid=1339744329&sr=8-1 here are some notes and links:   Evolved from Cybernetics, General Systems Theory, Synergetics some interesting transdisciplinary fields to investigate: Chaos Theory - http://en.wikipedia.org/wiki/Chaos_theory – small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for chaotic systems, rendering long-term prediction impossible. System Dynamics / Cybernetics - http://en.wikipedia.org/wiki/System_Dynamics – study of how feedback changes system behavior Network Theory - http://en.wikipedia.org/wiki/Network_theory – leverage Graph Theory to analyze symmetric  / asymmetric relations between discrete objects Algebraic Topology - http://en.wikipedia.org/wiki/Algebraic_topology – leverage abstract algebra to analyze topological spaces There are limits to deterministic systems & to computation. Chaos Theory definitely applies to training an ANN (artificial neural network) – different weights will emerge depending upon the random selection of the training set. In recursive Non-Linear systems http://en.wikipedia.org/wiki/Nonlinear_system – output is not directly inferable from input. E.g. a Logistic map: Xt+1 = R Xt(1-Xt) Different types of bifurcations, attractor states and oscillations may occur – e.g. a Lorenz Attractor http://en.wikipedia.org/wiki/Lorenz_system Feigenbaum Constants http://en.wikipedia.org/wiki/Feigenbaum_constants express ratios in a bifurcation diagram for a non-linear map – the convergent limit of R (the rate of period-doubling bifurcations) is 4.6692016 Maxwell’s Demon - http://en.wikipedia.org/wiki/Maxwell%27s_demon - the Second Law of Thermodynamics has only a statistical certainty – the universe (and thus information) tends towards entropy. While any computation can theoretically be done without expending energy, with finite memory, the act of erasing memory is permanent and increases entropy. Life & thought is a counter-example to the universe’s tendency towards entropy. Leo Szilard and later Claude Shannon came up with the Information Theory of Entropy - http://en.wikipedia.org/wiki/Entropy_(information_theory) whereby Shannon entropy quantifies the expected value of a message’s information in bits in order to determine channel capacity and leverage Coding Theory (compression analysis). Ludwig Boltzmann came up with Statistical Mechanics - http://en.wikipedia.org/wiki/Statistical_mechanics – whereby our Newtonian perception of continuous reality is a probabilistic and statistical aggregate of many discrete quantum microstates. This is relevant for Quantum Information Theory http://en.wikipedia.org/wiki/Quantum_information and the Physics of Information - http://en.wikipedia.org/wiki/Physical_information. Hilbert’s Problems http://en.wikipedia.org/wiki/Hilbert's_problems pondered whether mathematics is complete, consistent, and decidable (the Decision Problem – http://en.wikipedia.org/wiki/Entscheidungsproblem – is there always an algorithm that can determine whether a statement is true).  Godel’s Incompleteness Theorems http://en.wikipedia.org/wiki/G%C3%B6del's_incompleteness_theorems  proved that mathematics cannot be both complete and consistent (e.g. “This statement is not provable”). Turing through the use of Turing Machines (http://en.wikipedia.org/wiki/Turing_machine symbol processors that can prove mathematical statements) and Universal Turing Machines (http://en.wikipedia.org/wiki/Universal_Turing_machine Turing Machines that can emulate other any Turing Machine via accepting programs as well as data as input symbols) that computation is limited by demonstrating the Halting Problem http://en.wikipedia.org/wiki/Halting_problem (is is not possible to know when a program will complete – you cannot build an infinite loop detector). You may be used to thinking of 1 / 2 / 3 dimensional systems, but Fractal http://en.wikipedia.org/wiki/Fractal systems are defined by self-similarity & have non-integer Hausdorff Dimensions !!!  http://en.wikipedia.org/wiki/List_of_fractals_by_Hausdorff_dimension – the fractal dimension quantifies the number of copies of a self similar object at each level of detail – eg Koch Snowflake - http://en.wikipedia.org/wiki/Koch_snowflake Definitions of complexity: size, Shannon entropy, Algorithmic Information Content (http://en.wikipedia.org/wiki/Algorithmic_information_theory - size of shortest program that can generate a description of an object) Logical depth (amount of info processed), thermodynamic depth (resources required). Complexity is statistical and fractal. John Von Neumann’s other machine was the Self-Reproducing Automaton http://en.wikipedia.org/wiki/Self-replicating_machine  . Cellular Automata http://en.wikipedia.org/wiki/Cellular_automaton are alternative form of Universal Turing machine to traditional Von Neumann machines where grid cells are locally synchronized with their neighbors according to a rule. Conway’s Game of Life http://en.wikipedia.org/wiki/Conway's_Game_of_Life demonstrates various emergent constructs such as “Glider Guns” and “Spaceships”. Cellular Automatons are not practical because logical ops require a large number of cells – wasteful & inefficient. There are no compilers or general program languages available for Cellular Automatons (as far as I am aware). Random Boolean Networks http://en.wikipedia.org/wiki/Boolean_network are extensions of cellular automata where nodes are connected at random (not to spatial neighbors) and each node has its own rule –> they demonstrate the emergence of complex  & self organized behavior. Stephen Wolfram’s (creator of Mathematica, so give him the benefit of the doubt) New Kind of Science http://en.wikipedia.org/wiki/A_New_Kind_of_Science proposes the universe may be a discrete Finite State Automata http://en.wikipedia.org/wiki/Finite-state_machine whereby reality emerges from simple rules. I am 2/3 through this book. It is feasible that the universe is quantum discrete at the plank scale and that it computes itself – Digital Physics: http://en.wikipedia.org/wiki/Digital_physics – a simulated reality? Anyway, all behavior is supposedly derived from simple algorithmic rules & falls into 4 patterns: uniform , nested / cyclical, random (Rule 30 http://en.wikipedia.org/wiki/Rule_30) & mixed (Rule 110 - http://en.wikipedia.org/wiki/Rule_110 localized structures – it is this that is interesting). interaction between colliding propagating signal inputs is then information processing. Wolfram proposes the Principle of Computational Equivalence - http://mathworld.wolfram.com/PrincipleofComputationalEquivalence.html - all processes that are not obviously simple can be viewed as computations of equivalent sophistication. Meaning in information may emerge from analogy & conceptual slippages – see the CopyCat program: http://cognitrn.psych.indiana.edu/rgoldsto/courses/concepts/copycat.pdf Scale Free Networks http://en.wikipedia.org/wiki/Scale-free_network have a distribution governed by a Power Law (http://en.wikipedia.org/wiki/Power_law - much more common than Normal Distribution). They are characterized by hubs (resilience to random deletion of nodes), heterogeneity of degree values, self similarity, & small world structure. They grow via preferential attachment http://en.wikipedia.org/wiki/Preferential_attachment – tipping points triggered by positive feedback loops. 2 theories of cascading system failures in complex systems are Self-Organized Criticality http://en.wikipedia.org/wiki/Self-organized_criticality and Highly Optimized Tolerance http://en.wikipedia.org/wiki/Highly_optimized_tolerance. Computational Mechanics http://en.wikipedia.org/wiki/Computational_mechanics – use of computational methods to study phenomena governed by the principles of mechanics. This book is a great intuition pump, but does not cover the more mathematical subject of Computational Complexity Theory – http://en.wikipedia.org/wiki/Computational_complexity_theory I am currently reading this book on this subject: http://www.amazon.com/Computational-Complexity-Christos-H-Papadimitriou/dp/0201530821/ref=pd_sim_b_1   stay tuned for that review!

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  • guvcview recording video and audio out of synchronisation in Ubuntu 10.10

    - by SIJAR
    I finally got Guvcview, a great software for Logitech webcam and it does all the stuff that one wants out of it. But I'm not satisfy with the video recording, video and audio out of synchronisation also video seems to be in slow motion. Please help so that I can tweak in and get a good video recording with the webcam. Below is the log of Guvcview ------------------------------------------------------------------------------- guvcview 1.4.1 video_device: /dev/video0 vid_sleep: 0 cap_meth: 1 resolution: 640 x 480 windowsize: 1024 x 715 vert pane: 578 spin behavior: 0 mode: mjpg fps: 1/25 Display Fps: 0 bpp: 0 hwaccel: 1 avi_format: 4 sound: 1 sound Device: 4 sound samp rate: 0 sound Channels: 0 Sound delay: 0 nanosec Sound Format: 85 Pan Step: 2 degrees Tilt Step: 2 degrees Video Filter Flags: 0 image inc: 0 profile(default):/home/sijar/default.gpfl starting portaudio... bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) Cannot connect to server socket err = No such file or directory Cannot connect to server socket jack server is not running or cannot be started language catalog= dir:/usr/share/locale type:UTF-8 lang:en_US.utf8 cat:guvcview.mo mjpg: setting format to 1196444237 capture method = 1 video device: /dev/video0 libv4lconvert: warning more framesizes then I can handle! libv4lconvert: warning more framesizes then I can handle! /dev/video0 - device 1 libv4lconvert: warning more framesizes then I can handle! libv4lconvert: warning more framesizes then I can handle! Init. UVC Camera (046d:0825) (location: usb-0000:00:1d.7-5) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 176 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 432, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 544, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 640, height = 360 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, ... repeats a couple of times ... vid:046d pid:0825 driver:uvcvideo Adding control for Pan (relative) UVCIOC_CTRL_ADD - Error: Operation not permitted checking format: 1196444237 VIDIOC_G_COMP:: Invalid argument compression control not supported fps is set to 1/25 drawing controls control[0]: 0x980900 Brightness, 0:255:1, default 128 control[0]: 0x980901 Contrast, 0:255:1, default 32 control[0]: 0x980902 Saturation, 0:255:1, default 32 control[0]: 0x98090c White Balance Temperature, Auto, 0:1:1, default 1 control[0]: 0x980913 Gain, 0:255:1, default 0 control[0]: 0x980918 Power Line Frequency, 0:2:1, default 2 control[0]: 0x98091a White Balance Temperature, 0:10000:10, default 4000 control[0]: 0x98091b Sharpness, 0:255:1, default 24 control[0]: 0x98091c Backlight Compensation, 0:1:1, default 1 control[0]: 0x9a0901 Exposure, Auto, 0:3:1, default 3 control[0]: 0x9a0902 Exposure (Absolute), 1:10000:1, default 166 control[0]: 0x9a0903 Exposure, Auto Priority, 0:1:1, default 0 resolutions of format(2) = 19 frame rates of 1º resolution=6 Def. Res: 0 numb. fps:6 --------------------------------------- device #0 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 (hw:0,0) Host API = ALSA Max inputs = 2, Max outputs = 2 Def. low input latency = 0.012 Def. low output latency = 0.012 Def. high input latency = 0.046 Def. high output latency = 0.046 Def. sample rate = 44100.00 --------------------------------------- device #1 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 - MIC ADC (hw:0,1) Host API = ALSA Max inputs = 2, Max outputs = 0 Def. low input latency = 0.011 Def. low output latency = -1.000 Def. high input latency = 0.043 Def. high output latency = -1.000 Def. sample rate = 48000.00 --------------------------------------- device #2 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 - MIC2 ADC (hw:0,2) Host API = ALSA Max inputs = 2, Max outputs = 0 Def. low input latency = 0.011 Def. low output latency = -1.000 Def. high input latency = 0.043 Def. high output latency = -1.000 Def. sample rate = 48000.00 --------------------------------------- device #3 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 - ADC2 (hw:0,3) Host API = ALSA Max inputs = 2, Max outputs = 0 Def. low input latency = 0.011 Def. low output latency = -1.000 Def. high input latency = 0.043 Def. high output latency = -1.000 Def. sample rate = 48000.00 --------------------------------------- device #4 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 - IEC958 (hw:0,4) Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.011 Def. high input latency = -1.000 Def. high output latency = 0.043 Def. sample rate = 48000.00 --------------------------------------- device #5 Name = USB Device 0x46d:0x825: USB Audio (hw:1,0) Host API = ALSA Max inputs = 1, Max outputs = 0 Def. low input latency = 0.011 Def. low output latency = -1.000 Def. high input latency = 0.043 Def. high output latency = -1.000 Def. sample rate = 48000.00 --------------------------------------- device #6 Name = front Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.012 Def. high input latency = -1.000 Def. high output latency = 0.046 Def. sample rate = 44100.00 --------------------------------------- device #7 Name = iec958 Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.011 Def. high input latency = -1.000 Def. high output latency = 0.043 Def. sample rate = 48000.00 --------------------------------------- device #8 Name = spdif Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.011 Def. high input latency = -1.000 Def. high output latency = 0.043 Def. sample rate = 48000.00 --------------------------------------- device #9 Name = pulse Host API = ALSA Max inputs = 32, Max outputs = 32 Def. low input latency = 0.012 Def. low output latency = 0.012 Def. high input latency = 0.046 Def. high output latency = 0.046 Def. sample rate = 44100.00 --------------------------------------- device #10 Name = dmix Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.043 Def. high input latency = -1.000 Def. high output latency = 0.043 Def. sample rate = 48000.00 --------------------------------------- device #11 [ Default Input, Default Output ] Name = default Host API = ALSA Max inputs = 32, Max outputs = 32 Def. low input latency = 0.012 Def. low output latency = 0.012 Def. high input latency = 0.046 Def. high output latency = 0.046 Def. sample rate = 44100.00 ---------------------------------------------- SampleRate:0 Channels:0 Video driver: x11 A window manager is available VIDIOC_S_EXT_CTRLS for multiple controls failed (error -1) using VIDIOC_S_CTRL for user class controls control(0x0098091a) "White Balance Temperature" failed to set (error -1) VIDIOC_S_EXT_CTRLS for multiple controls failed (error -1) using VIDIOC_S_EXT_CTRLS on single controls for class: 0x009a0000 control(0x009a0902) "Exposure (Absolute)" failed to set (error -1) VIDIOC_S_EXT_CTRLS for multiple controls failed (error -1) using VIDIOC_S_CTRL for user class controls control(0x0098091a) "White Balance Temperature" failed to set (error -1) VIDIOC_S_EXT_CTRLS for multiple controls failed (error -1) using VIDIOC_S_EXT_CTRLS on single controls for class: 0x009a0000 control(0x009a0902) "Exposure (Absolute)" failed to set (error -1) Cap Video toggled: 1 (/home/sijar/Videos/Webcam) 25371756K bytes free on a total of 39908968K (used: 36 %) treshold=51200K using audio codec: 0x0055 Audio frame size is 1152 samples for selected codec IO thread started...OK [libx264 @ 0x8cbd8b0]using cpu capabilities: MMX2 SSE2 Cache64 [libx264 @ 0x8cbd8b0]profile Baseline, level 3.0 [libx264 @ 0x8cbd8b0]non-strictly-monotonic PTS shift sound by -9 ms shift sound by -9 ms shift sound by -9 ms AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data ... repeats a couple of times ... AUDIO: droping audio data (/home/sijar/Videos/Webcam) 25371748K bytes free on a total of 39908968K (used: 36 %) treshold=51200K AUDIO: droping audio data AUDIO: droping audio data ... repeats a couple of times ... Cap Video toggled: 0 Shuting Down IO Thread AUDIO: droping audio data stop= 4426644744000 start=4416533023000 VIDEO: 146 frames in 10111.000000 ms = 14.439719 fps Stoping audio stream Closing audio stream... close avi Last message repeated 145 times [libx264 @ 0x8cbd8b0]frame I:2 Avg QP:14.10 size: 24492 [libx264 @ 0x8cbd8b0]frame P:103 Avg QP:16.06 size: 20715 [libx264 @ 0x8cbd8b0]mb I I16..4: 48.4% 0.0% 51.6% [libx264 @ 0x8cbd8b0]mb P I16..4: 57.5% 0.0% 0.0% P16..4: 40.2% 0.0% 0.0% 0.0% 0.0% skip: 2.3% [libx264 @ 0x8cbd8b0]final ratefactor: 62.05 [libx264 @ 0x8cbd8b0]coded y,uvDC,uvAC intra: 79.7% 92.2% 68.4% inter: 62.4% 87.5% 48.0% [libx264 @ 0x8cbd8b0]i16 v,h,dc,p: 23% 17% 41% 19% [libx264 @ 0x8cbd8b0]i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 30% 24% 26% 2% 5% 3% 3% 3% 4% [libx264 @ 0x8cbd8b0]i8c dc,h,v,p: 53% 20% 23% 4% [libx264 @ 0x8cbd8b0]ref P L0: 63.0% 37.0% [libx264 @ 0x8cbd8b0]kb/s:-0.00 total frames encoded: 0 total audio frames encoded: 0 IO thread finished...OK IO Thread finished enabling controls Cap Video toggled: 1 (/home/sijar/Videos/Webcam) 25379744K bytes free on a total of 39908968K (used: 36 %) treshold=51200K using audio codec: 0x0055 Audio frame size is 1152 samples for selected codec IO thread started...OK [libx264 @ 0x8cfba20]using cpu capabilities: MMX2 SSE2 Cache64 [libx264 @ 0x8cfba20]profile Baseline, level 3.0 [libx264 @ 0x8cfba20]non-strictly-monotonic PTS shift sound by -236 ms shift sound by -236 ms shift sound by -236 ms (/home/sijar/Videos/Webcam) 25377044K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25373408K bytes free on a total of 39908968K (used: 36 %) treshold=51200K AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data ... repeats a couple of times ... (/home/sijar/Videos/Webcam) 25370696K bytes free on a total of 39908968K (used: 36 %) treshold=51200K AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data ... repeats a couple of times ... (/home/sijar/Videos/Webcam) 25367680K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25364052K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25360312K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25356628K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25352908K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25349316K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25345552K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25341828K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25338092K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25334412K bytes free on a total of 39908968K (used: 36 %) treshold=51200K Cap Video toggled: 0 Shuting Down IO Thread stop= 4708817235000 start=4578624714000 VIDEO: 1604 frames in 130192.000000 ms = 12.320265 fps Stoping audio stream Closing audio stream... close avi Last message repeated 1603 times [libx264 @ 0x8cfba20]frame I:16 Avg QP:14.78 size: 42627 [libx264 @ 0x8cfba20]frame P:1547 Avg QP:16.44 size: 28599 [libx264 @ 0x8cfba20]mb I I16..4: 21.6% 0.0% 78.4% [libx264 @ 0x8cfba20]mb P I16..4: 28.1% 0.0% 0.0% P16..4: 70.5% 0.0% 0.0% 0.0% 0.0% skip: 1.4% [libx264 @ 0x8cfba20]final ratefactor: 88.17 [libx264 @ 0x8cfba20]coded y,uvDC,uvAC intra: 74.4% 95.8% 83.2% inter: 75.2% 94.6% 69.2% [libx264 @ 0x8cfba20]i16 v,h,dc,p: 27% 17% 40% 16% [libx264 @ 0x8cfba20]i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 25% 21% 3% 6% 4% 5% 4% 7% [libx264 @ 0x8cfba20]i8c dc,h,v,p: 61% 18% 18% 4% [libx264 @ 0x8cfba20]ref P L0: 64.0% 36.0% [libx264 @ 0x8cfba20]kb/s:-0.00 total frames encoded: 0 total audio frames encoded: 0 IO thread finished...OK IO Thread finished enabling controls Shuting Down Thread Thread terminated... cleaning Thread allocations: 100% SDL Quit Video Thread finished write /home/sijar/.guvcviewrc OK free audio mutex closed v4l2 strutures free controls free controls - vidState cleaned allocations - 100% Closing portaudio ...OK Closing GTK... OK

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  • DELETE method not working in Apache 2.4

    - by Xavi
    I'm running Apache 2.4 locally and dealing with RESTful services authenticating through OAuth. GET, PUT and POST work fine but I can't get DELETE to work. I've tried installing WebDAV and mod_dav, overriding methods in .htaccess, tried Limits, force (enable) DELETE options in configuration and pretty much everything I've found in Google and StackExchange. Here's a copy of my .htaccess right now: <IfModule mod_rewrite.c> Header add Access-Control-Allow-Origin: * Header add Access-Control-Allow-Headers: Authorization Header add Access-Control-Allow-Headers: X-Requested-With Header add Access-Control-Request-Method: HEAD Header add Access-Control-Request-Method: GET Header add Access-Control-Request-Method: PUT Header add Access-Control-Request-Method: DELETE Header add Access-Control-Request-Method: OPTIONS Options +FollowSymlinks Options -Indexes RewriteEngine on RewriteRule ^(.*)\.* index.php [NC,L] </IfModule> Chrome's console shows: XMLHttpRequest cannot load http://dev.server.com/cars/favourite/. Method DELETE is not allowed by Access-Control-Allow-Methods. Is there anything I am missing?

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  • Visual WebGui launches a new prize-winning challenge for developers

    - by Webgui
    Gizmox is announcing a ListView Challenge where developers can participate by creating and submitting their own implementations of the new extended ListView. "its quite amazing what you can do with it. It opens a lot of new ways to present data in a better and more userfriendly way," says one of the VWG community members who built a three level hierarchal ListView. Watch the hierarchal ListView demo by Visualizer Those ListView implementations will be reviewed and rated and the winner will win a free Professional Studio license $750 worth. The 5 top rated codes will entitle their developers for a cool new T-shirt. The new v6.4 introduces new capabilities with its extended ListView Control. Enter the Challenge The Collapsible Panel enhancement of the ListView Control, along with the Column Type Control, open up the possibilities for potential usage of the ListView control for data display, data entry and as the Collapsible Panel can contain whatever control you like, it can as well contain other ListView controls, thus making it possible to create Hierarchial ListView display of unlimited number of levels. The first enhancement is the introduction of a new column type Control which opens up the possibility for a ListView cell to contain controls like CheckBox, ComboBox, ListBox or even TabControl, Form or another ListView as the contents of that particular cell. This means that the ListView is no longer a display-only control, but has the full potential of being a full blown data entry control as well. The second major enhancement is the introduction of ListViewPanelItem. The ListViewPanelItem behaves exactly the same as it‘s predecessor, the ListViewItem, and in additon it has a Panel Control attached to it, seperate panel for each row in the ListView. This new Panel can be either expanded (visible) or not (hidden) and when expanded, will fill the full width of the ListView, but has adjustable height. Watch a webcast about the extended ListView

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  • Clean MVC design when there is viewer latency

    - by Tony Suffolk 66
    It isn't clear if this question has already been answered, so apologies in advance if this is a duplicate : I am implementing a game and trying to design around a clean MVC pattern - so my Control plane will implement the rules of the game (but not how the game is displayed), and the View plane implements how the game is displayed, and user iteraction - i.e. what game items or controls the user has activated. The challenge that I have is this : In my game the Control Plane can move game items more or less instaneously (The decision about what item to place where - and some of the initial consequences of that placement are reasonably trivial to calculate), but I want to design the Control Plane so that the View plane can display these movements either instaneously or using movement animations. The other complication is that player interaction must be locked out while those game items are moving (similar to chess - you can't attack an opposing piece as it moves past one of your pieces) So do I : Implement all the logic in the Control Plane asynchronously - and separate the descision making from the actions - so the Control plane decides piece 'A' needs to move to a given place - tells the view plane, and but does not implement the move in data until the view plane informs the control plane that the move/animation is complete. A lot of interlock points between the two layers. Implement all the control plane logic in one place - decisions and movement (keeping track of what moved where), and pass all the movements in one go to the View plane to do with what it will. Control Plane is almost fire and forget here. A hybrid of 1 & 2 - The control plane implements all the moves in a temporary data store - but maintains a second store which reflects what is actually visible to the viewer, based on calls and feedback from the View plane. All 3 are relatively easy to implement (target language is python), but having never done a clean MVC pattern with view latency before - I am not sure which design is best

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  • Examples of different architecture methodologies

    - by Lane
    Is there a resource or site which illustrates building the same application (desktop or web) using several different contrasting architectures? Such as MVP versus MVVM versus MVC, etc. It would be very helpful to see how they look side-by-side using real-world code instead of comparing written theory to written theory. I've often found that something can be described well in a book, but when you go to implement it, the subtleties and weaknesses of the theory become readily apparent.

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  • In WPF, how do I get a command in a Control Template to bind to a property in a parent?

    - by Keith
    I am relatively new to WPF and sometimes it makes my head explode. However, I do like the power behind it, especially when used with the MVVM model. I have a control template that contains a button. I use that control template inside of a custom control. I want to add a property on the custom control that will bind to the command property of the button inside the control template. Basically, it is a combo box with a button to the right of it to allow a user to pop up a search dialog. Since this control could appear on a usercontrol multiple times, I need to be able to potentially bind each control to a different command (Searh products, search customers, etc). However, I have been unable to figure out how to do this Here is some sample XAML <Style TargetType="{x:Type m:SelectionFieldControl}"> <Setter Property="LookupTemplate" Value="{StaticResource LookupTemplate}" /> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type m:SelectionFieldControl}"> <Border BorderThickness="{TemplateBinding Border.BorderThickness}" Padding="{TemplateBinding Control.Padding}" BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" SnapsToDevicePixels="True" Focusable="False"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" MinWidth="0" SharedSizeGroup="{Binding LabelShareSizeGroupName, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type m:BaseFieldControl}}}" /> <ColumnDefinition Width="1*" /> <ColumnDefinition Width="Auto" SharedSizeGroup="{Binding WidgetsShareSizeGroupName, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type m:BaseFieldControl}}}" /> </Grid.ColumnDefinitions> <!-- Customized Value Part --> <ComboBox x:Name="PART_Value" Grid.Column="1" Margin="4,2,0,1" SelectedValue="{Binding Path=SelectionField.Value, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type m:SelectionFieldControl}}}" IsEnabled="{Binding Field.IsNotReadOnly, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type m:SelectionFieldControl}}}" Visibility="{Binding Field.IsInEditMode, Converter={StaticResource TrueToVisible}, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type m:SelectionFieldControl}}}" FontFamily="{StaticResource FontFamily_Default}" FontSize="11px"> <ComboBox.ItemsPanel> <ItemsPanelTemplate> <VirtualizingStackPanel IsVirtualizing="True" VirtualizationMode="Recycling"/> </ItemsPanelTemplate> </ComboBox.ItemsPanel> </ComboBox> <StackPanel Grid.Column="2" Orientation="Horizontal" Name="PART_Extra" Focusable="False"> <ContentControl Name="PART_LookupContent" Template="{Binding LookupTemplate, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type m:SelectionFieldControl}}}" Focusable="False"/> </StackPanel> </Grid> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> I thought I could get it to work by doing something like this <Button Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type SelectionFieldControl}}, Path=ShowSearchCommand}" Margin="2" /> but it does not work. Any help would be greatly appreciated.

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