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• How to make a piece of WPF content take up the entire application window

  - by Bojin Li

  I'm working on an application that contains a number of content areas. I want to implement a behavior such that in response to user input, any of these content areas can be toggled to fit the entire application window, and optionally back to its original position again. I experimented with several approaches and none of them seem optimal for me. Here's what I tried to do: Use the ClipToBoundsProperty on the content I want to make "Full Screen": Doesn't work because only the CanvasPanel seems to fully respect this property. The application need to be localized so I would really like to avoid the CanvasPanel. Use a Grid and collapse the other content areas, such that only the one I want to see is visible, hence taking up the entire screen: This will probably work but doesn't seem easy to implement nor maintain. The "Full Screen" content area could be several levels deep, for example residing inside a Tabcontrol, so I would have to hide the tab headers too etc. Reconstruct the content area in a separate view and display it while hiding the rest: Seems easy enough to do with DataTemplates and my ViewModel objects, but any GUI/View only states are not preserved using this approach. Somehow "lift" the GUI/View I want to "Full Screen" into the separate view and display it while hiding the rest: I don't know how to do this or even if this is possible. Anyway if anyone knows a better approach I would love to know about it. Thanks a lot!

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• How do I deal with different requests that map to the same response?

  - by daxim

  I'm designing a Web service. The request is idempotent, so I chose the GET method. The response is relatively expensive to calculate and not small, so I want to get caching (on the protocol level) right. (Don't worry about memoisation at my part, I have that already covered; my question here is actually also paying attention to the Web as a whole.) There's only one mandatory parameter and a number of optional parameter with default values if missing. For example, the following two map to the same representation of the response. (If this is a dumb way to go about it the interface, propose something better.) GET /service?mandatory_parameter=some_data HTTP/1.1 GET /service?mandatory_parameter=some_data;optional_parameter=default1;another_optional_parameter=default2;yet_another_optional_parameter=default3 HTTP/1.1 However, I imagine clients do not know this and would treat them separate and therefore waste cache storage. What should I do to avoid violating the golden rule of caching? Make up a canonical form, document it (e.g. all parameters are required after all and need to be sorted in a specific order) and return a client error unless the required form is met? Instead of an error, redirect permanently to the canonical form of a request? Or is it enough to not mind how the request looks like, and just respond with the same ETag for same responses?

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• Is there any good reason for private methods existence in C# (and OOP in general)?

  - by Piotr Lopusiewicz

  I don't mean to troll but I really don't get it. Why would language designers allow private methods instead of some naming convention (see __ in Python) ? I searched for the answer and usual arguments are: a) To make the implementation cleaner/avoid long vertical list of methods in IDE autocompletion b) To announce to the world which methods are public interface and which may change and are just for implementation purpose c) Readability Ok so now, all of those could be achieved by naming all private methods with __ prefix or by "private" keyword which doesn't have any implications other than be information for IDE (don't put those in autocompletion) and other programers (don't use it unless you really must). Hell, one could even require unsafe-like keyword to access private methods to really discourage this. I am asking this because I work with some c# code and I keep changing private methods to public for test purposes as many in-between private methods (like string generators for xml serialization) are very useful for debugging purposes (like writing some part of string to log file etc.). So my question is: Is there anything which is achieved by access restriction but couldn't be achieved by naming conventions without restricting the access ?

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• How to use CellRenderer for GregorianCalendar?

  - by HansDampf

  So I have been trying to use the example from Tutorial and change it so it fits my program. The getColumnValue method returns the object that holds the information that is supposed to be displayed. Is this the way to go or should it rather return the actual String to be displayed. I guess not because that way I would mix the presentation with the data, which I was trying to avoid. public class IssueTableFormat implements TableFormat<Appointment> { public int getColumnCount() { return 6; } public String getColumnName(int column) { if(column == 0) return "Datum"; else if(column == 1) return "Uhrzeit"; else if(column == 2) return "Nummer"; else if(column == 3) return "Name"; else if(column == 4) return "letzte Aktion"; else if(column == 5) return "Kommentar"; throw new IllegalStateException(); } public Object getColumnValue(Appointment issue, int column) { if(column == 0) return issue.getDate(); else if(column == 1) return issue.getDate(); else if(column == 2) return issue.getSample(); else if(column == 3) return issue.getSample(); else if(column == 4) return issue.getHistory(); else if(column == 5) return issue.getComment(); throw new IllegalStateException(); } } The column 0 and 1 contain a GregorianCalendar object, but I want column 0 to show the date and 1 to show the time. So I know using cellRenderers can help here. This is what I tried. public class DateRenderer extends DefaultTableCellRenderer { public DateRenderer() { super(); } public void setValue(Object value) { GregorianCalendar g =(GregorianCalendar) value; value=g.get(GregorianCalendar.HOUR); } } But the cell doesnt show anything, what is wrong here?

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• Sanitizing usser input before adding it to the DOM in Javascript

  - by I GIVE TERRIBLE ADVICE

  I'm writing the JS for a chat appication I'm working on in my free time, and I need to have HTML identifiers that change according to user submitted data. This is usually something conceptually shaky enough that I would not even attempt it, but I don't see myself having much of a choice this time. What I need to do then is to escape the HTML id to make sure it won't allow for XSS or breaking HTML. Here's the code: var user_id = escape(id) var txt = '<div class="chut">'+ '<div class="log" id="chut_'+user_id+'"></div>'+ '<textarea id="chut_'+user_id+'_msg"></textarea>'+ '<label for="chut_'+user_id+'_to">To:</label>'+ '<input type="text" id="chut_'+user_id+'_to" value='+user_id+' readonly="readonly" />'+ '<input type="submit" id="chut_'+user_id+'_send" value="Message"/>'+ '</div>'; What would be the best way to escape id to avoid any kind of problem mentioned above? As you can see, right now I'm using the built-in escape() function, but I'm not sure of how good this is supposed to be compared to other alternatives. I'm mostly used to sanitizing input before it goes in a text node, not an id itself.

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• Redirecting http to https for a directory, via .htaccess, using mod_alias only

  - by Belinda

  I have the common problem of wanting to redirect requests for a certain restricted access directory from http to https, so that users' login credentials are sent in a secure way. However, I do not have mod_rewrite enabled on my server. I only have mod_alias. This means I have to use the RedirectMatch command. I can't use the usual solutions that use RewriteCond and RewriteRule. (A note on the politics: I am a small-fry subsite maintainer in a very large organisation, so the server admins are unlikely to be willing to change the server config for me!) The following line works, but forms an infinite loop (because the rewritten URL is still caught by the initial regular expression): RedirectMatch permanent ^/intranet(.*)$ https://example.com/intranet$1 One of my internal IT guys has suggested I avoid the infinite loop by moving the files to a new directory with a new name (eg /intranet2/). That seems pretty ugly to me. And people could still accidentally/deliberately revert to an insecure connection by visiting http://example.com/intranet2/ directly. Then I tried this, but it didn't work: RedirectMatch permanent ^http:(.*)/intranet(.*)$ https://example.com/intranet$1 I suspect it didn't work because the first argument must be a file path from the root directory, so it can't start with "http:". So: any better ideas how to do this?

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• Regular Expressions, avoiding HTML tags in PHP

  - by Jason Axelrod

  I have actually seen this question quite a bit here, but none of them are exactly what I want... Lets say I have the following phrase: Line 1 - This is a TEST phrase. Line 2 - This is a <img src="TEST" /> image. Line 3 - This is a <a href="somelink/TEST">TEST</a> link. Okay, simple right? I am trying the following code: $linkPin = '#(\b)TEST(\b)(?![^<]*>)#i'; $linkRpl = '$1<a href="newurl">TEST</a>$2'; $html = preg_replace($linkPin, $linkRpl, $html); As you can see, it takes the word TEST, and replaces it with a link to test. The regular expression I am using right now works good to avoid replacing the TEST in line 2, it also avoids replacing the TEST in the href of line 3. However, it still replaces the text encapsulated within the tag on line 3 and I end up with: Line 1 - This is a <a href="newurl">TEST</a> phrase. Line 2 - This is a <img src="TEST" /> image. Line 3 - This is a <a href="somelink/TEST"><a href="newurl">TEST</a></a> link. This I do not want as it creates bad code in line 3. I want to not only ignore matches inside of a tag, but also encapsulated by them. (remember to keep note of the / in line 2)

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• Calculating with a variable outside of its bounds in C

  - by aquanar

  If I make a calculation with a variable where an intermediate part of the calculation goes higher then the bounds of that variable type, is there any hazard that some platforms may not like? This is an example of what I'm asking: int a, b; a=30000; b=(a*32000)/32767; I have compiled this, and it does give the correct answer of 29297 (well, within truncating error, anyway). But the part that worries me is that 30,000*32,000 = 960,000,000, which is a 30-bit number, and thus cannot be stored in a 16-bit int. The end result is well within the bounds of an int, but I was expecting that whatever working part of memory would have the same size allocated as the largest source variables did, so an overflow error would occur. This is just a small example to show my problem, I am trying to avoid using floating points by making the fraction be a fraction of the max amount able to be stored in that variable (in this case, a signed integer, so 32767 on the positive side), because the embedded system I'm using I believe does not have an FPU. So how do most processors handle calculations out of the bounds of the source and destination variables?

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• How to multi-thread this?

  - by WilliamKF

  I wish to have two threads. The first thread1 occasionally calls the following pseudo function: void waitForThread2() { if (thread2 is not idle) { return; } notifyThread2IamReady(); while (thread2IsExclusive) { } } The second thread2 is forever in the following pseudo loop: for (;;) { Notify thread1 I am idle. while (!thread1IsReady()) { } Notify thread1 I am exclusive. Do some work while thread1 is blocked. Notify thread1 I am busy. Do some work in parallel with thread1. } What is the best way to write this such that both thread1 and thread2 are kept as busy as possible on a machine with multiple cores. I would like to avoid long delays between notification in one thread and detection by the other. I tried using pthread condition variables but found the delay between thread2 doing 'notify thread1 I am busy' and the loop in waitForThread2() on thear2IsExclusive() can be up to almost one second delay. I then tried using a volatile sig_atomic_t shared variable to control the same, but something is going wrong, so I must not be doing it correctly.

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• Union and order by

  - by David Lively

  Consider a table like tbl_ranks -------------------------------- family_id | item_id | view_count -------------------------------- 1 10 101 1 11 112 1 13 109 2 21 101 2 22 112 2 23 109 3 30 101 3 31 112 3 33 109 4 40 101 4 51 112 4 63 109 5 80 101 5 81 112 5 88 109 I need to generate a result set with the top two(2) rows for a subset of family ids (say, 1,2,3 and 4) ordered by view count. I'd like to do something like select top 2 * from tbl_ranks where family_id = 1 order by view_count union all select top 2 * from tbl_ranks where family_id = 2 order by view_count union all select top 2 * from tbl_ranks where family_id = 3 order by view_count union all select top 2 * from tbl_ranks where family_id = 4 order by view_count but, of course, order by isn't valid in a union all context in this manner. Any suggestions? I know I could run a set of 4 queries, store the results into a temp table and select the contents of that temp as the final result, but I'd rather avoid using a temp table if possible. Note: in the real app, the number of records per family id is indeterminate, and the view_counts are also not fixed as they appear in the above example.

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• Replacing repetitively occuring loops with eval in Javascript - good or bad?

  - by Herc

  Hello stackoverflow! I have a certain loop occurring several times in various functions in my code. To illustrate with an example, it's pretty much along the lines of the following: for (var i=0;i<= 5; i++) { function1(function2(arr[i],i),$('div'+i)); $('span'+i).value = function3(arr[i]); } Where i is the loop counter of course. For the sake of reducing my code size and avoid repeating the loop declaration, I thought I should replace it with the following: function loop(s) { for (var i=0;i<= 5; i++) { eval(s); } } [...] loop("function1(function2(arr[i],i),$('div'+i));$('span'+i).value = function3(arr[i]);"); Or should I? I've heard a lot about eval() slowing code execution and I'd like it to work as fast as a proper loop even in the Nintendo DSi browser, but I'd also like to cut down on code. What would you suggest? Thank you in advance!

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• Additional information in ASP.Net MVC View

  - by Max Malmgren

  I am attempting to implement a custom locale service in an MVC 2 webpage. I have an interface IResourceDictionary that provides a couple of methods for accessing resources by culture. This is because I want to avoid the static classes of .Net resources. The problem is accessing the chosen IResourceDictionary from the views. I have contemplated using the ViewDataDictionary given, creating a base controller from which all my controllers inherits that adds my IResourceDictionary to the ViewData before each action executes. Then I could call my resource dictionary this way: (ViewData["Resources"] as IResourceDictionary).GetEntry(params); Admittedly, this is extremely verbose and ugly, especially in inline code as we are encouraged to use in MVC. Right now I am leaning towards static class access ResourceDictionary.GetEntry(params); because it is slightly more elegant. I also thought about adding it to my typed model for each page, which seems more robust than adding it to the ViewData.. What is the preferred way to access my ResourceDictionary from the views? All my views will be using this dictionary.

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• JS window.close() let IE hang

  - by p4bl0.666

  Hi all, for reason I won't bore you with, I'm writing an asp.net application that must open some pages in new browser windows. I managed to open them within a postback (don't ask why, I just needed to) with this code: script = String.Format(@"window.open(""{0}"", ""{1}"");", url, target); ScriptManager.RegisterStartupScript(page, typeof(Page), "Redirect", script, true); Now I have new windows each one with a button that should close it. I have simply an onclick="window.close()" (but that prompts me when I'm closing the browser) or window.open('','_self','');window.close() (horrible, I agree but it's the only way I found to avoid the JS prompt) On firefox it works perfectly but on IE7 (the browser our customers have) after 2-3 times I use that button to close the window I can't open other windows (in both cases, with or without the JS prompt). With the method above it does nothing, and with a <a href="mypage.aspx" target="_blank">click me</a> a new window is opened but hangs on loading (it doesn't even calls the Page_Load). What could be the cause? How can I solve this? Thank you.

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• Android - How to approach fall detection algorithm

  - by bobby123

  I want to be able to feature a fairly simple fall detection algorithm in my application. At the moment in onSensorChanged(), I am getting the absolute value of the current x,x,z values and subtracting SensorManager.GRAVITY_EARTH (9.8 m/s) from this. The resulting value has to be bigger than a threshold value 10 times in a row to set a flag saying a fall has been detected by the accelerometer, the threshold value is about 8m/s. Also I'm comparing the orientation of the phone as soon as the threshold has been passed and the orienation of it when the threshold is no longer being passed, this sets another flag saying the orientation sensor has detected a fall. When both flags are set, an event occurs to check is user ok, etc etc. My problem is with the threshold, when the phone is held straight up the absolute value of accelerometer is about 9.8 m/s, but when i hold it still at an angle it can be over 15m/s. This is causing other events to trigger the fall detection, and if i increase the threshold to avoid that, it won't detect falls. Can anyone give me some advice here with what possible values i should use or how to even improve my method? Many thanks.

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• codeigniter avoiding html div's

  - by rabidmachine9

  Hello there!Is there a proper syntax to avoid div's in codeigniter? I don't really like opening and closing tags all the time... <div class="theForm"> <?php echo form_open('edit/links');//this form uploads echo "Enter the Name: ". form_input('name','name'); echo "Enter the Link: ". form_input('url','url'); echo " ".form_submit('submit', 'Submit'); echo form_close(); if (isset($linksQuery) && count($linksQuery)){ foreach($linksQuery as $link){ echo anchor($link['link'], $link['name'].".", array("class" => "links")); echo form_open('edit/links',array('class' => 'deleteForm')); echo form_hidden('name',$link['name']); echo " ".form_submit('delete','Delete'); echo form_close(); echo br(2); } } ?> </div>

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• Problem with running totals in jquery

  - by rshivers

  I'm having an issue trying to get an accurate running total for my calculations. When you enter numbers into the input field I get an accurate total for that line item, but the grand total comes out to a higher number. Note that this is a dynamic form and that the id's will change depending on how many form fields I have added to the form. Also, I have it set to make the calculations onKeyUp for each input field instead of a calculate button. The code that calculates a single item is this: function calcLineItem(id) { var id = $(id).attr("id"); var Item1 = $("#Item1" + id).val(); var Item2 = $("#Item2" + id).val(); var Item3 = $("#Item3" + id).val(); function calcTotal(Item1, Item2, Item3){ var total; total = Math.round((Item1 * Item2) * Item3); return total; } $("#total" + id).text(calcTotal(Item1, Item2, Item3)); calcAllFields(); } This will give me the total of this particular input field. The function at the end, calcAllFields(), is supposed to do the calculations for all items in my form to give me the grand total of all input fields: function calcAllFields(id) { var id = $(id).attr("id"); $('#target1').text($("#total" + id).map(function() { var currentValue = parseFloat(document.getElementById("currentTotal").value); var newValue = parseFloat($("#total" + id).text()); var newTotal = currentValue + newValue; document.getElementById("currentTotal").value = newTotal; return newTotal; }).get().join()); } The variable currentTotal is getting its value from a hidden field on my form: <input type="hidden" id="currentTotal" value="0"> As I enter numbers a field the calculation for that line will be accurate, but the grand total will be inaccurate because the value for currentTotal will continue to increment with every key stroke I make in the input field. Any ideas on how to avoid this from happening?

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• Access php multidimensional array key based on a variable string

  - by ggirtsou

  I have stored the XML path to items in a string like this: response->items->item. What I need to do is to access an array called $xml_array like this: $xml_array['response']['items']['item'] When I write it in the code it works. The thing is that I want it to be done on the fly. I use this to convert response->items->item to ['response']['items']['item']: $xml_path = 'response->items->item'; $explode_path = explode('->', $xml_path); $correct_string = false; foreach($explode_path as $path) { $correct_string .= '[\''.$path.'\']'; } the problem is that I can't access $xml_array by doing this: $xml_array[$correct_string] So I end up with this: $xml_tag = 'title'; $xml_path = 'response->items->item'; $correct_string = '$items = $xml2array'; $explode_path = explode('->', $xml_path); foreach($explode_path as $path) { $correct_string .= '[\''.$path.'\']'; } $correct_string .= ';'; eval($correct_string); foreach($items as $item) { echo $item[$xml_tag].'<br />'; } and access the $xml_array array through $items array. Is there any way I can do this and avoid using eval()? Thanks in advance!

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• Avoiding repetition with libraries that use a setup + execute model

  - by lijie

  Some libraries offer the ability to separate setup and execution, esp if the setup portion has undesirable characteristics such as unbounded latency. If the program needs to have this reflected in its structure, then it is natural to have: void setupXXX(...); // which calls the setup stuff void doXXX(...); // which calls the execute stuff The problem with this is that the structure of setupXXX and doXXX is going to be quite similar (at least textually -- control flow will prob be more complex in doXXX). Wondering if there are any ways to avoid this. Example: Let's say we're doing signal processing: filtering with a known kernel in the frequency domain. so, setupXXX and doXXX would probably be something like... void doFilter(FilterStuff *c) { for (int i = 0; i < c->N; ++i) { doFFT(c->x[i], c->fft_forward_setup, c->tmp); doMultiplyVector(c->tmp, c->filter); doFFT(c->tmp, c->fft_inverse_setup, c->x[i]); } } void setupFilter(FilterStuff *c) { setupFFT(..., &(c->fft_forward_setup)); // assign the kernel to c->filter ... setupFFT(..., &(c->fft_inverse_setup)); }

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• Issue in alternate Row color using each() method of JQuery

  - by user1323981

  I have a table as under <table > <tr> <th scope="col">EmpId</th><th scope="col">EmpName</th> </tr> <tr> <td>1</td><td>ABC</td> </tr> <tr> <td>2</td><td>DEF</td> </tr> </table> I want to set the alternate row color of only the "td" elements of the table and not "th" by using only each() function. I have tried with <style type="text/css"> tr.even { background-color: green; } tr.odd { background-color: yellow; } </style> $(document).ready(function () { $('table > tbody').each(function () { $('tr:odd', this).addClass('odd').removeClass('even'); $('tr:even', this).addClass('even').removeClass('odd'); }); }); Though this works but it accepts also "th" element. How to avoid that? Please help Thanks

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• Strategy for animation a lot of LED's - thread?, UIView animations? NSOperation? (iPhone)

  - by RickiG

  Hi I have to do some different views containing 72 LED lights. I built an LED Class so I can loop through the LED's and set them to different colors (Green, Red, Orange, Blue None etc.). The LED then loads the appropriate .png. This works fine, I loop over the LED's and set them. Now I know that at some time they will need to not just turn on/off change color, but will have to turn on with a small delay. Like an equalizer. I have a 5-10 views containing the 72 LED's and I would like to achieve the above with the minimum amount of memory/CPU strain. for(LED *l in self.ledArray) { [l display:Green]; } I simply loop as shown above and inside the LED is a switch case that does the correct logic. If this were actual LED's and a microController I would use sleep(100) or similar in the loop, but I would really like to avoid stuff like that for obvious reasons. I was thinking that doing a performOnThread withDelay would really be consuming, so would UIView animation changing the alpha and NSOperation would also be a lot of lifting for a small feature. Is there a both efficient and clever way to go around this? Thanks for any inspiration given:)

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• Reference properteries declared in a protocol and implemented in the anonymous category?

  - by Heath Borders

  I have the following protocol: @protocol MyProtocol @property (nonatomic, retain) NSObject *myProtocolProperty; -(void) myProtocolMethod; @end and I have the following class: @interface MyClass : NSObject { } @end I have a class extension declared, I have to redeclare my protocol properties here or else I can't implement them with the rest of my class. @interface()<MyProtocol> @property (nonatomic, retain) NSObject *myExtensionProperty; /* * This redeclaration is required or my @synthesize myProtocolProperty fails */ @property (nonatomic, retain) NSObject *myProtocolProperty; - (void) myExtensionMethod; @end @implementation MyClass @synthesize myProtocolProperty = _myProtocolProperty; @synthesize myExtensionProperty = _myExtensionProperty; - (void) myProtocolMethod { } - (void) myExtensionMethod { } @end In a consumer method, I can call my protocol methods and properties just fine. Calling my extension methods and properties produces a warning and an error respectively. - (void) consumeMyClassWithMyProtocol: (MyClass<MyProtocol> *) myClassWithMyProtocol { myClassWithMyProtocol.myProtocolProperty; // works, yay! [myClassWithMyProtocol myProtocolMethod]; // works, yay! myClassWithMyProtocol.myExtensionProperty; // compiler error, yay! [myClassWithMyProtocol myExtensionMethod]; // compiler warning, yay! } Is there any way I can avoid redeclaring the properties in MyProtocol within my class extension in order to implement MyProtocol privately?

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• The cross-thread usage of "HttpContext.Current" property and related things

  - by smwikipedia

  I read from < Essential ASP.NET with Examples in C# the following statement: Another useful property to know about is the static Current property of the HttpContext class. This property always points to the current instance of the HttpContext class for the request being serviced. This can be convenient if you are writing helper classes that will be used from pages or other pipeline classes and may need to access the context for whatever reason. By using the static Current property to retrieve the context, you can avoid passing a reference to it to helper classes. For example, the class shown in Listing 4-1 uses the Current property of the context to access the QueryString and print something to the current response buffer. Note that for this static property to be correctly initialized, the caller must be executing on the original request thread, so if you have spawned additional threads to perform work during a request, you must take care to provide access to the context class yourself. I am wondering about the root cause of the bold part, and one thing leads to another, here is my thoughts: We know that a process can have multiple threads. Each of these threads have their own stacks, respectively. These threads also have access to a shared memory area, the heap. The stack then, as I understand it, is kind of where all the context for that thread is stored. For a thread to access something in the heap it must use a pointer, and the pointer is stored on its stack. So when we make some cross-thread calls, we must make sure that all the necessary context info is passed from the caller thread's stack to the callee thread's stack. But I am not quite sure if I made any mistake. Any comments will be deeply appreciated. Thanks. ADD Here the stack is limited to user stack.

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• MySql: Is it reasonable to use 'view' or I would better denormalize my DB?

  - by Budda

  There is 'team_sector' table with following fields: Id, team_id, sect_id, size, level It contains few records for each 'team' entity (referenced with 'team_id' field). Each record represent sector of team's stadium (totally 8 sectors). Now it is necessary to implement few searches: by overall stadium size (SUM(size)); the best quality (SUM(level)/COUNT(*)). I could create query something like this: SELECT TS.team_id, SUM(TS.size) as OverallSize, SUM(TS.Level)/COUNT(TS.Id) AS QualityLevel FROM team_sector GROUP BY team_id ORDER BY OverallSize DESC / ORDER BY QualityLevel DESC But my concern here is that calculation for each team will be done each time on query performed. It is not too big overhead (at least now), but I would like to avoid performance issues later. I see 2 options here. The 1st one is to create 2 additional fields in 'team' table (for example) and store there OverallSize and QualityLevel fields. If information if 'sector' table is changed - update those table too (probably would be good to do that with triggers, as sector table doesn't change too often). The 2nd option is to create a view that will provide required data. The 2nd option seems much easier for me, but I don't have a lot of experience/knowledge of work with views. Q1: What is the best option from your perspective here and why? Probably you could suggest other options? Q2: Can I create view in such way that it will do calculations rarely (at least once per day)? If yes - how? Q3: Is it reasonable to use triggers for such purpose (1st option). P.S. MySql 5.1 is used, overall number of teams is around 1-2 thousand, overall number of records in sector table - overall 6-8 thousand. I understand, those numbers are pretty small, but I would like to implement the best practice here.

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• Nested/Sub data types in haskell

  - by Tom Carstens

  So what would be nice is if you could do something like the following (not necessarily with this format, just the general idea): data Minor = MinorA | MinorB data Major = Minor | MajorB isMinor :: Major -> Bool isMinor Minor = True isMinor _ = False So isMinor MinorA would report True (instead of an error.) At the moment you might do something like: data Major = MinorA | MinorB | MajorB isMinor :: Major -> Bool isMinor MinorA = True isMinor MinorB = True isMinor _ = False It's not terrible or anything, but it doesn't expand nicely (as in if Minor when up to MinorZ this would be terribly clunky). To avoid that problem you can wrap Minor: data Minor = MinorA | MinorB data Major = MajorA Minor | MajorB isMinor :: Major -> Bool isMinor (MajorA _) = True isMinor _ = False But now you have to make sure to wrap your Minors to use them as a Major... again not terrible; just doesn't really express the semantics I'd like very well (i.e. Major can be any Minor or MajorB). The first (legal) example is "Major can be MinorA..." but doesn't have any knowledge of Minor and the second is "Major can be MajorA that takes a Minor..." p.s. No, this isn't really about anything concrete.

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• Update MySQl table onDrop?

  - by dougvt

  Hi all. I am writing a PHP/MySQL application (using CodeIgniter) that uses some jQuery functionality for dragging table rows. I have a table in which the user can drag rows to the desired order (kind of a queue for which I need to preserve the rank of each row). I've been trying to figure out how to (and whether I should) update the database each time the user drops a row, in order to simplify the UI and avoid a "Save" button. I have the jQuery working and can send a serialized list back to the server onDrop, but is it good design practice to run an update query this often? The table will usually have 30-40 rows max, but if the user drags row 1 far down the list, then potentially all the rows would need to be updated to update the rank field. I've been wondering whether to send a giant query to the server, to loop through the rows in PHP and update each row with its own Update query, to send a small serialized list to a stored procedure to let the server do all the work, or perhaps a better method I haven't considered. I've read that stored procedures in MySQL are not very efficient and use a separate process for each call. Any advice as to the right solution here? Thanks very much for your help!

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