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  • selecting text by ignoring inner Elements of div tag javascript

    - by sugar
    <html> <body> <script language="javascript"> function getSelectionHTML() { var div = document.getElementById("myDiv").childNodes; if (document.createRange) { var textNode=div.firstChild; var rangeObj=document.createRange(); rangeObj.setStart(textNode,0); rangeObj.setEnd(textNode,10); selRange.collapse(true); var elem = document.getElementById('myDiv') elem .innerHTML = elem .innerHTML.replace(rangeObj.toString(), '<span style="background-color: lime">'+rangeObj.toString()+'</span>') } } </script> <div id="myDiv"> asdf as<b>dfas df asf asdf sdfjk dvh a sjkh jhcdjkv</b> iof scjahjkv ahsjv hdjk biud fcsvjksdhf k </div> <form name="aform"> <input type="button" value="Get selection" onclick="getSelectionHTML()"> </body> </html> Ok. Let me explain - getSelectionHTML() method is for selection of characters from 0 to 10. I am getting the values by "myDiv" id. but inner bold, italic & other tags are putting me in trouble. In simple words, I just want to make selection of first ten characters (& apply them span tag) which are in "myDiv" tag. What exactly I am missing ? Can anyone help me ? Thanks in advance for sharing your knowledge. Sagar.

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  • using jquery $.ajax to retrieve data and push data into javascript array through the success functio

    - by teamdane
    Hello All, I have a function that I'm trying to retrieve values using $.ajax and push the returned data into an array called output. Problem is the success function will not allow me to push the results into the array. see below for code. var getValues = function(el) { var value = ($(el).val()); if(value == '' || $(el).attr('disabled')) { return []; } var string = 'value=' + value; var output = []; $.ajax({ type: "GET", url: 'shocklookup_callback.php', dataType: "string", data: string, success: function(data) { } }); //output.push({ text : value + 'test', value : value + 'test1'} ); return output; }; Any ideas of what I can put in the success function to be able to push the data into the output array? Also I need to be able to return the output array to the original function getValues. If this doesn't' make a whole lot of sense please let me know and I'll try to explain better. Thanks, Dane

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  • Pointer and malloc issue

    - by Andy
    I am fairly new to C and am getting stuck with arrays and pointers when they refer to strings. I can ask for input of 2 numbers (ints) and then return the one I want (first number or second number) without any issues. But when I request names and try to return them, the program crashes after I enter the first name and not sure why. In theory I am looking to reserve memory for the first name, and then expand it to include a second name. Can anyone explain why this breaks? Thanks! #include <stdio.h> #include <stdlib.h> void main () { int NumItems = 0; NumItems += 1; char* NameList = malloc(sizeof(char[10])*NumItems); printf("Please enter name #1: \n"); scanf("%9s", NameList[0]); fpurge(stdin); NumItems += 1; NameList = realloc(NameList,sizeof(char[10])*NumItems); printf("Please enter name #2: \n"); scanf("%9s", NameList[1]); fpurge(stdin); printf("The first name is: %s",NameList[0]); printf("The second name is: %s",NameList[1]); return 0; }

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  • Simple aggregating query very slow in PostgreSql, any way to improve?

    - by Ash
    HI I have a table which holds files and their types such as CREATE TABLE files ( id SERIAL PRIMARY KEY, name VARCHAR(255), filetype VARCHAR(255), ... ); and another table for holding file properties such as CREATE TABLE properties ( id SERIAL PRIMARY KEY, file_id INTEGER CONSTRAINT fk_files REFERENCES files(id), size INTEGER, ... // other property fields ); The file_id field has an index. The file table has around 800k lines, and the properties table around 200k (not all files necessarily have/need a properties). I want to do aggregating queries, for example find the average size and standard deviation for all file types. But it's very slow - around 70 seconds for the latter query. I understand it needs a sequential scan, but still it seems too much. Here's the query SELECT f.filetype, avg(size), stddev(size) FROM files as f, properties as pr WHERE f.id = pr.file_id GROUP BY f.filetype; and the explain HashAggregate (cost=140292.20..140293.94 rows=116 width=13) (actual time=74013.621..74013.954 rows=110 loops=1) -> Hash Join (cost=6780.19..138945.47 rows=179564 width=13) (actual time=1520.104..73156.531 rows=179499 loops=1) Hash Cond: (f.id = pr.file_id) -> Seq Scan on files f (cost=0.00..108365.41 rows=1140941 width=9) (actual time=0.998..62569.628 rows=805270 loops=1) -> Hash (cost=3658.64..3658.64 rows=179564 width=12) (actual time=1131.053..1131.053 rows=179499 loops=1) -> Seq Scan on properties pr (cost=0.00..3658.64 rows=179564 width=12) (actual time=0.753..557.171 rows=179574 loops=1) Total runtime: 74014.520 ms Any ideas why it is so slow/how to make it faster?

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  • Can a conforming C# compiler optimize away a local (but unused) variable if it is the only strong re

    - by stakx
    The title says it all, but let me explain: void Case_1() { var weakRef = new WeakReference(new object()); GC.Collect(); // <-- doesn't have to be an explicit call; just assume that // garbage collection would occur at this point. if (weakRef.IsAlive) ... } In this code example, I obviously have to plan for the possibility that the new'ed object is reclaimed by the garbage collector; therefore the if statement. (Note that I'm using weakRef for the sole purpose of checking if the new'ed object is still around.) void Case_2() { var unusedLocalVar = new object(); var weakRef = new WeakReference(unusedLocalVar); GC.Collect(); // <-- doesn't have to be an explicit call; just assume that // garbage collection would occur at this point. Debug.Assert(weakReferenceToUseless.IsAlive); } The main change in this code example from the previous one is that the new'ed object is strongly referenced by a local variable (unusedLocalVar). However, this variable is never used again after the weak reference (weakRef) has been created. Question: Is a conforming C# compiler allowed to optimize the first two lines of Case_2 into those of Case_1 if it sees that unusedLocalVar is only used in one place, namely as an argument to the WeakReference constructor? i.e. is there any possibility that the assertion in Case_2 could ever fail?

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  • Entity Framework EntityKey / Foreign Key problem.

    - by Ronny176
    Hi, I keep getting the same error: Entities in 'VlaamseOverheidMeterEntities.ObjectMeter' participate in the 'FK_ObjectMeter_Meter' relationship. 0 related 'Meter' were found. 1 'Meter' is expected. I have the following table structure: Meter 1 <- * ObjectMeter * - 1 VO_Object It is always the same scenario: The first meter is added to the database, the second meter gives the error above. I have the following code in my manager: public List<string> addTemporary(string username, string meterNaam, string readingType, string parentID) { Meter meter = new Meter(); VO_Object voObject = objectManager.getObjectByID(parentID); ObjectMeter objMeter = new ObjectMeter(); meter.readingType = (int)Enum.Parse(typeof(ReadingType), readingType); meter.isActive = true; meter.name = meterNaam; meter.startDate = DateTime.Now; meter.endDate = DateTime.Now.AddYears(6000); meter.uniqueIdentifier = "N/A"; meter.meterType = (int)Enum.Parse(typeof(MeterType), "NA"); meter.meterCategory = (int)Enum.Parse(typeof(MeterCategory), "NA"); meter.energyType = (int)Enum.Parse(typeof(EnergyType), "NA"); meter.utilityType = (int)Enum.Parse(typeof(UtilityType), "NA"); meter.unitOfMeasure = (int)Enum.Parse(typeof(UnitOfMeasure), "NA"); objMeter.valid_from = meter.startDate; objMeter.valid_until = meter.endDate; objMeter.Meter = meter; objMeter.VO_Object = voObject; createMeter(meter); List<String> str = new List<string>(); str.Add("" + meter.meterID); str.Add(meter.name); return str; } and this in my Dao Class which links to the database: internal void CreateMeter(Meter _meter) { _entities.AddToMeter(_meter); _entities.SaveChanges(); } Can someone please explain this error? Ronald

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  • VS2010 and CSS: What is the best way to position a single form control

    - by George
    OK, I have a ton of controls on my page that I need to individually place. I need to set a margin here, a padding there, etc. None of these particular styles that I want to apply will be applied to more than control. What is the bets practice for determining at which level the style is placed, etc? OK, my choices are 1) External CSS file 1A) Using ClientIdMode = Auto (the default) I could assign a unique CssClass value to the ASP.NET control and, in the external CSS file, create a class selector that would only be applied to that one control. 1B) User Client ID = Predicatable In the external CSS file, I could determine what the ID will be for the controls of interest and create an ID selector (#ControlID{Style} ). However, I fear maintenance issues due to including/removing parent containers that would cause the ID to change. 1C) User Client ID = Static. I could choose static IDs for the controls such that I minimize the likelihood of a clash with auto generated IDs (perhaps by prefixing the ID with "StaticID_" and use an external stylesheet with ID selectors. 2) I could place the style right on the control. The only disadvantage here, as I see it, is that style info is brought down each time instead of being cached , which is what I'd get using an external CSS. If a style isn't resused, I personally don't see much benefit to placing it in an external file, though please explain why if you disagree. Is there moire of a reason that "It's nice to have all the CSS in one place?"

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  • Testing Web Application: "Mirror" ad-hoc testing in another window

    - by Narcissus
    I don't even really know if the title is the best way to explain what I'm trying to do, but anyway... We have a web app that is being ported to a number of DB backends via MDB2. Our unit tests are pretty lacking at the moment, but our internal users are pretty good at knowing what to test to see if things are broken. What I'm 'imagining' is a browser plug in (don't really care which browser it is for) or a similar system that essentially takes every event from one window and 'mirrors' it in the other browser/s. The reason I'd like this is so that I can have various installations that use different DB backends, and have the user open a window/tab to each installation. From there, however, I'd like them to be able to 'work' in one window and have that 'work' I occur at the same time in each of the 'cloned' windows. From there, they should be able to do some quick eyeballing of the information that comes back, without having to worry about timing differences and so (very much). I know it's a big ask, but I figure if anyone knows of a solution, I'd find it here... Any thoughts?

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  • Troubleshooting multiple GET variables In PHP

    - by V413HAV
    This may be a very simple question but I don't what's the wrong thing am doing here... To explain you clearly, I've set a real simple example below: <ul> <li><a href="test.php?link1=true">Link 1</a></li> <li><a href="test.php?link2=true">Link 2</a></li> <li><a href="test.php?link3=true">Link 3</a></li> </ul> <?php if(isset($_GET['link1'])) { if(($_GET['link1']) == 'true') { echo 'This Is Link 1'; } } if(isset($_GET['link2'])) { if(($_GET['link2']) == 'true') { echo 'This Is Link 2'; } } if(isset($_GET['link3'])) { if(($_GET['link3']) == 'true') { echo 'This Is Link 3'; } } ?> This is a test.php page, here I've set 3 different arguments for $_GET, and show contents accordingly, now everything works perfect, the only thing am not understanding is how to block this kind of url say if user clicks on link 1 the url will be : http://localhost/test.php?link1=true And the Output of this url is This is Link 1 Now if I change this url to : http://localhost/test.php?link3=true&link2=true&link1=true And the Output what I get is This Is Link 1This Is Link 2This Is Link 3 Now this is ok here, but it's very annoying if someone types this and see's forms one below the other, any way I can stop this tampering?

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  • What is a good "Error Checking" Pattern (Java)?

    - by Jack
    I'll explain what I mean by input error checking. Say you have a function doSomething(x). If the function completes successfully doSomething does something and returns nothing. However, if there are errors I'd like to be notified. That is what I mean by error checking. I'm looking for, in general, the best way to check for errors. I've thought of the following solutions, each with a potential problem. Flag error checking. If doSomething(x) completes successfully return null. Otherwise, it returns a boolean or an error string. Problem: Side effects. Throwing an exception. Throw an exception if doSomething(x) encounters an error. Problem: If you are performing error checking for parameters only, throwing an IllegalArgumentExceptionseems inappropriate. Validating input prior to function call. If the error checking is only meant for the parameters of the function, then you can call a validator function before calling the doSomething(x) function. Problem: What if a client of the class forgets to call the validator function before calling doSomething(x)? I often encounter this problem and any help or a point in the right direction would be much appreciated.

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  • C++/Qt - Memory allocation question

    - by HardCoder1986
    Hello! I recently started investigating Qt for myself and have the following question: Suppose I have some QTreeWidget* widget. At some moment I want to add some items to it and this is done via the following call: QList<QTreeWidgetItem*> items; // Prepare the items QTreeWidgetItem* item1 = new QTreeWidgetItem(...); QTreeWidgetItem* item2 = new QTreeWidgetItem(...); items.append(item1); items.append(item2); widget->addTopLevelItems(items); So far it looks ok, but I don't actually understand who should control the objects' lifetime. I should explain this with an example: Let's say, another function calls widget->clear();. I don't know what happens beneath this call but I do think that memory allocated for item1 and item2 doesn't get disposed here, because their ownage wasn't actually transfered. And, bang, we have a memory leak. The question is the following - does Qt have something to offer for this kind of situation? I could use boost::shared_ptr or any other smart pointer and write something like shared_ptr<QTreeWidgetItem> ptr(new QTreeWidgetItem(...)); items.append(ptr.get()); but I don't know if the Qt itself would try to make explicit delete calls on my pointers (which would be disastrous since I state them as shared_ptr-managed). How would you solve this problem? Maybe everything is evident and I miss something really simple?

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  • Migrating Ajax web application to web socket

    - by Bastan
    Hi, I think i'm just missing a little detail that is preventing me from seeing the whole picture. I have a web application which use ajax request every x time to update client with new information or tasks. I also have a long running process on the server which is a java computation engine. I would like this engine to send update to the client. I am wondering how to migrate my web app to using websocket. Probably phpwebsocket or similar. Can my server 'decide' to send information to a specific client? It seems possible looking at the php-websocket. Can my java backend long process use the websocket server to send notification to a specific client. How? well I can say that my java app could use a class that could send over websocket instead of http. But how the websocket server knows to which client to send the 'info'. I am puzzle by all this. Any document that explain this in more details? It seems that the websocket could create an instance of my web application. Thanks

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  • Java Variable Initialization

    - by Samuel Brainard
    Here's a piece of code I wrote. public class cube { private int length; private int breadth; private int height; private int volume; private int density; private int weight; public cube(int l,int b,int h, int d) { length=l; breadth=b; height=h; density=d; } public void volmeShow(){ volume=length*breadth*height; System.out.println("The Volume of the cube is "+this.volume); So if I implement the above cube class like this, public class cubeApp { public static void main(String[] args){ cube mycube = new cube(5,6,9,2); mycube.volumeShow(); I get an output that tells me Volume is 270. But I get an output that says Volume is 0 if I define the volume variable like this: public class cube { private int length; private int breadth; private int height; private int volume=length*breadth*height; private int density; private int weight; public cube(int l,int b,int h, int d) { length=l; breadth=b; height=h; density=d; } public void volmeShow(){ System.out.println("The Volume of the cube is "+this.volume); Can somebody please explain why this is happening? Thanks, Samuel.

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  • int array doesnt get char values

    - by user1780004
    I am absolutely brand new at programming and im not sure how to explain what im doing here. The whole purpose of this piece is to enter values and then print them out in the same order. Now I wanna quit from entering values when pressing 'q' and so I have to scanf for chars but when I assign them back to the int array the values are not the same. Hope that makes any sense to you but in any case heres my code: #include <stdio.h> #include <stdlib.h> #define SIZE 5000 define flush fflush(stdin) main() { int input[SIZE] = {0},i = 0; int counter = 0; char inputs, quit; do { system("cls"); printf("Input number ('q' to quit and display numbers entered): "); flush; scanf("%c",&inputs); flush; if (inputs == 'q') quit = 'q'; else { input[i] = inputs; counter++; i++; } } while (i < SIZE && quit != 'q'); for(i = 0; i < counter; i++){ printf("%i.%i\n", i + 1, input[i]); } system("pause"); } Ive been trying to do this on my own btw and also researched some information online regarding chars but couldnt find anything that would help me. Thanks a lot in advance.

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  • Sequential searching with sorted linked lists

    - by John Graveston
    struct Record_node* Sequential_search(struct Record_node *List, int target) { struct Record_node *cur; cur = List->head ; if(cur == NULL || cur->key >= target) { return NULL; } while(cur->next != NULL) { if(cur->next->key >= target) { return cur; } cur = cur->next; } return cur; } I cannot interpret this pseudocode. Can anybody explain to me how this program works and flows? Given this pseudocode that searches for a value in a linked list and a list that is in an ascending order, what would this program return? a. The largest value in the list that is smaller than target b. The largest value in the list that is smaller than or same as target c. The smallest value in the list that is larger than or same as target d. Target e. The smallest value in the list that is larger than target And say that List is [1, 2, 4, 5, 9, 20, 20, 24, 44, 69, 70, 71, 74, 77, 92] and target 15, how many comparisons are occurred? (here, comparison means comparing the value of target)

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  • Why does setting the margin on a div not affect the position of child content?

    - by DanM
    I'd like to understand a little more clearly how css margins work with divs and child content. If I try this... <div style="clear: both; margin-top: 2em;"> <input type="submit" value="Save" /> </div> ...the Save button is right up against the User Role (margin fail): If I change it to this... <div style="clear: both;"> <input style="margin-top: 2em;" type="submit" value="Save" /> </div> ...there is a gap between the Save button and the User Role (margin win): Questions: Can someone explain what I'm observing? Why doesn't putting a margin on the div cause the input to move down? Why must I put the margin on the input itself? There must be some fundamental law of css I am not grasping.

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  • Open new UserControl in the mainWindows

    - by user287964
    Hi I have this snippet public partial class Window1 : Window { public Window1() { InitializeComponent(); } private void ToggleButton_Checked(object sender, RoutedEventArgs e) { switch ((sender as Button).Content.ToString()) { case "UserControl 1": AddItemToContainer(new UserControl1()); break; case "UserControl 2": AddItemToContainer(new UserControl2()); break; case "UserControl 3": AddItemToContainer(new UserControl3()); break; default: break; } } void AddItemToContainer(UIElement _myElement) { Grid.SetColumn(_myElement, 1); HostContainer.Children.Add(_myElement); } } } } With this I can open a new userControl in myMainwindow Let’s say something like adding child to myMainWinodw,Now I’m trying to click on a button from my userControl so I open another userControl that take the place of the first one I explain: I have the mainWindows it has 3 button first one to open the first UserControl the second one to open the second userControl and the third to open the last UserControl,imagine that I opened the first UserControl let’s call it UC1, In the UC1 I have a button to open the second userControl (let’s call it UC2) I like that when I clik the button from the UC1 the UC2 is opened and take the place of the UC1 (of course the UC2 is still a child of myMainWinodw) I have alredy try to call the AddItemToContainer methode from other methode but nothing is happened Any suggestion please

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  • .net web service annoying issue

    - by JL
    Excuse the title, but it's best I just explain the problem. I have 2 projects in my solution A Class Library A Web Application, which consists of a web service (asmx). the web service has code sitting in the app_code folder, with a file [webservicename].cs Inside the webservice code behind class, I have a web method here is a sample example (its simplified): [WebMethod] public EnumTaskExportState ProcessTask() { var tm = new UploadTaskManager(); return tm.ProcessTask(); } Now at design time, in visual studio (2010 or 2008), when I right click on UploadTaskMananger, and then select "Go to definition". I get taken to AppData\Temp[some folder structure]...etc.... and it displays the public class definition. Instead I would like to have complete integration, so that I get taken directly to the actual class in the class library project. My guess is, this is happening because I am using the app_code route, and not a compiled file for the web service class. But I don't know any other way to do this. How can I fix this? Possibly do away with the need for the app_code directory?

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  • getting windows username with javascript

    - by jbkkd
    I have a site which is built in ASP.net and C#. Let's call it webapp. it uses a Form system to log on into it, and cannot be changed easliy. I got a request to change the log in to some kind of windows authentication. I'll explain. Our windows login uses active directory for users to log into their windows account. their login name is sXXXXXXX. X are numbers. in my webapp, I want to take the users numbers from their active directory login, and check if those exist in the webapp database. if it exists, they will automatically log in. If it doesn't, they will be referred to the regular login page for the webapp system which is currently in use. I tried changing my IIS to disable anonymous login and enabling windows authentication, therefore making the user browser to send it's current logged in user name to my webapp. I changed the web config as well from "Forms" to "Windows", which made my whole webapp obsolete as the whole forms system did not work. My question is this - is there a different way for the browser only to send the username to my webapp? I thought maybe javascript, I just don't know how to implement that, if it's even possible. I know it's not very secure, but all this platform and system is built outside the internet, it's on a private network.

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  • [jQuery] How to load vtip tooltip on a dynamically generated element?

    - by adaneko
    I'm new to jQuery and trying to combine the use of a tooltip plugin and a lightbox plugin. More specifically, I am using Colorbox (http://colorpowered.com/colorbox/) and vtip. Colorbox generates a div which displays an image like this: <div id="cboxLoadedContent" style="display: block; width: 400px; overflow: auto; height: 498px;"> <img src="image.jpg" id="cboxPhoto" style="margin: 49px auto auto; border: medium none; display: block; float: none; cursor: pointer;"> </div> I next add class="vtip" title="This is a tip." in order to use the vtip style, but for some reason it does not work when it's a title tag on an element dynamically generated by Colorbox, but works on anything already loaded on the page. Can anyone explain to me why this is and possibly offer some solutions to fix this problem?

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  • Ruby & ActiveRecord: referring to integer fields by (uniquely mapped) strings

    - by JP
    While its not my application a simple way to explain my problem is to assume I'm running a URL shortener. Rather than attempt to try and figure out what the next string I should use as the unique section of the URL, I just index all my URLs by integer and map the numbers to strings behind the scenes, essentially just changing the base of the number to, let's say, 62: a-z + A-Z + 0-9. In ActiveRecord I can easily alter the reader for the url_id field so that it returns my base 62 string instead of the number being stored in the database: class Short < ActiveRecord::Base def url_id i = read_attribute(:convo) return '0' if i == 0 s = '' while i > 0 s << CHARS[i.modulo(62)] i /= 62 end s end end but is there a way to tell ActiveRecord to accept Short.find(:first,:conditions=>{:url_id=>'Ab7'}), ie. putting the 'decoding' logic into my Short ActiveRecord class? I guess I could define my own def self.find_by_unique_string(string), but that feels like cheating somehow! Thanks!

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  • issue with tab bar view displaying a compound view

    - by ambertch
    I created a tab bar application, and I make the first tab a table. So I create a tableView controller, and go about setting the class identity of the view controller for the first tab to my tableView controller. This works fine, and I see the contents of the table filling up the whole screen. However, this is not what I actually want in the end goal - I would like a compound window having multiple views: - the aforementioned table - a custom view with data in it So what I do is create a nib for this content (call it contentNib), change the tab's class from the tableView controller to a generic UIViewController, and set the nib of that tab to this new contentNib. In this new contentNib I drag on a tableView and set File's Owner to the TableViewController. I then link the dataSource and delegate to file's owner (which is TableViewController). Surprisingly this does not work and I receive the error: **Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[UIViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 0x3b0f910'** This is bewildering to me since the file's owner is the TableViewController, which has been assigned to be both the dataSource and delegate. Does someone have either insight into my confusions, or a link to an example of how to have a compound view include a tableView? *update* I see this in the Apple TableView programming guide: "Note: You should use a UIViewController subclass rather than a subclass of UITableViewController to manage a table view if the view to be managed is composed of multiple subviews, one of which is a table view. The default behavior of the UITableViewController class is to make the table view fill the screen between the navigation bar and the tab bar (if either are present)." <----- I don't really get what this is telling me to do though... if someone can explain or point me to an example I'd be much appreciated!

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  • Help on MySQL table indexing when GROUP BY is used in a query

    - by Silver Light
    Thank you for your attention. There are two INNODB tables: Table authors id INT nickname VARCHAR(50) status ENUM('active', 'blocked') about TEXT Table books author_id INT title VARCHAR(150) I'm running a query against these tables, to get each author and a count of books he has: SELECT a. * , COUNT( b.id ) AS book_count FROM authors AS a, books AS b WHERE a.status != 'blocked' AND b.author_id = a.id GROUP BY a.id ORDER BY a.nickname This query is very slow (takes about 6 seconds to execute). I have an index on books.author_id and it works perfectly, but I do not know how to create an index on authors table, so that this query could use it. Here is how current EXPLAIN looks: id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE a ALL PRIMARY,id_status_nickname NULL NULL NULL 3305 Using where; Using temporary; Using filesort 1 SIMPLE b ref key_author_id key_author_id 5 a.id 2 Using where; Using index I've looked at MySQL manual on optimizing queries with group by, but could not figure out how I can apply it on my query. I'll appreciate any help and hints on this - what must be the index structure, so that MySQL could use it?

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  • How can this Ambient Context become null?

    - by Mark Seemann
    Can anyone help me explain how TimeProvider.Current can become null in the following class? public abstract class TimeProvider { private static TimeProvider current = DefaultTimeProvider.Instance; public static TimeProvider Current { get { return TimeProvider.current; } set { if (value == null) { throw new ArgumentNullException("value"); } TimeProvider.current = value; } } public abstract DateTime UtcNow { get; } public static void ResetToDefault() { TimeProvider.current = DefaultTimeProvider.Instance; } } Observations All unit tests that directly reference TimeProvider also invokes ResetToDefault() in their Fixture Teardown. There is no multithreaded code involved. Once in a while, one of the unit tests fail because TimeProvider.Current is null (NullReferenceException is thrown). This only happens when I run the entire suite, but not when I just run a single unit test, suggesting to me that there is some subtle test interdependence going on. It happens approximately once every five or six test runs. When a failure occurs, it seems to be occuring in the first executed tests that involves TimeProvider.Current. More than one test can fail, but only one fails in a given test run. FWIW, here's the DefaultTimeProvider class as well: public class DefaultTimeProvider : TimeProvider { private readonly static DefaultTimeProvider instance = new DefaultTimeProvider(); private DefaultTimeProvider() { } public override DateTime UtcNow { get { return DateTime.UtcNow; } } public static DefaultTimeProvider Instance { get { return DefaultTimeProvider.instance; } } } I suspect that there's some subtle interplay going on with static initialization where the runtime is actually allowed to access TimeProvider.Current before all static initialization has finished, but I can't quite put my finger on it. Any help is appreciated.

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  • Strange behaviour of DataTable with DataGridView

    - by Paul
    Please explain me what is happening. I have created a WinForms .NET application which has DataGridView on a form and should update database when DataGridView inline editing is used. Form has SqlDataAdapter _da with four SqlCommands bound to it. DataGridView is bound directly to DataTable _names. Such a CellValueChanged handler: private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e) { _da.Update(_names); } does not update database state although _names DataTable is updated. All the rows of _names have RowState == DataRowState.Unchanged Ok, I modified the handler: private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e) { DataRow row = _names.Rows[e.RowIndex]; row.BeginEdit(); row.EndEdit(); _da.Update(_names); } this variant really writes modified cell to database, but when I attempt to insert new row into grid, I get an error about an absence of row with index e.RowIndex So, I decided to improve the handler further: private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e) { if (_names.Rows.Count<e.RowIndex) { DataRow row = _names.Rows[e.RowIndex]; row.BeginEdit(); row.EndEdit(); } else { DataRow row = _names.NewRow(); row["NameText"] = dataGridView1["NameText", e.RowIndex].Value; _names.Rows.Add(row); } _da.Update(_names); } Now the really strange things happen when I insert new row to grid: the grid remains what it was until _names.Rows.Add(row); After this line THREE rows are inserted into table - two rows with the same value and one with Null value. The slightly modified code: DataRow row = _names.NewRow(); row["NameText"] = "--------------" _names.Rows.Add(row); inserts three rows with three different values: one as entered into the grid, the second with "--------------" value and third - with Null value. I really got stuck in guessing what is happening.

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