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  • Problem with memory leaks

    - by user191723
    Sorry, having difficulty formattin code to appear correct here??? I am trying to understand the readings I get from running instruments on my app which are telling me I am leaking memory. There are a number, quite a few in fact, that get reported from inside the Foundation, AVFoundation CoreGraphics etc that I assume I have no control over and so should ignore such as: Malloc 32 bytes: 96 bytes, AVFoundation, prepareToRecordQueue or Malloc 128 bytes: 128 bytes, CoreGraphics, open_handle_to_dylib_path Am I correct in assuming these are something the system will resolve? But then there are leaks that are reported that I believe I am responsible for, such as: This call reports against this line leaks 2.31KB [self createAVAudioRecorder:frameAudioFile]; Immediately followed by this: -(NSError*) createAVAudioRecorder: (NSString *)fileName { // flush recorder to start afresh [audioRecorder release]; audioRecorder = nil; // delete existing file to ensure we have clean start [self deleteFile: fileName]; VariableStore *singleton = [VariableStore sharedInstance]; // get full path to target file to create NSString *destinationString = [singleton.docsPath stringByAppendingPathComponent: fileName]; NSURL *destinationURL = [NSURL fileURLWithPath: destinationString]; // configure the recording settings NSMutableDictionary *recordSettings = [[NSMutableDictionary alloc] initWithCapacity:6]; //****** LEAKING 384 BYTES [recordSettings setObject:[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey: AVFormatIDKey]; //***** LEAKING 32 BYTES float sampleRate = 44100.0; [recordSettings setObject:[NSNumber numberWithFloat: sampleRate] forKey: AVSampleRateKey]; //***** LEAKING 48 BYTES [recordSettings setObject:[NSNumber numberWithInt:2] forKey:AVNumberOfChannelsKey]; int bitDepth = 16; [recordSettings setObject: [NSNumber numberWithInt:bitDepth] forKey:AVLinearPCMBitDepthKey]; //***** LEAKING 48 BYTES [recordSettings setObject:[NSNumber numberWithBool:YES] forKey:AVLinearPCMIsBigEndianKey]; [recordSettings setObject:[NSNumber numberWithBool: NO]forKey:AVLinearPCMIsFloatKey]; NSError *recorderSetupError = nil; // create the new recorder with target file audioRecorder = [[AVAudioRecorder alloc] initWithURL: destinationURL settings: recordSettings error: &recorderSetupError]; //***** LEAKING 1.31KB [recordSettings release]; recordSettings = nil; // check for erros if (recorderSetupError) { UIAlertView *alert = [[UIAlertView alloc] initWithTitle: @"Can't record" message: [recorderSetupError localizedDescription] delegate: nil cancelButtonTitle: @"OK" otherButtonTitles: nil]; [alert show]; [alert release]; alert = nil; return recorderSetupError; } [audioRecorder prepareToRecord]; //***** LEAKING 512 BYTES audioRecorder.delegate = self; return recorderSetupError; } I do not understand why there is a leak as I release audioRecorder at the start and set to nil and I release recordSettings and set to nil? Can anyone enlighten me please? Thanks

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  • Javascript InnerHTML Erases Data In Form Elements

    - by Jordan
    I have this form with a button that allows you to add fields to the form. <form id="contact" name="contactForm" action="newPoll.php" method="post"> <fieldset> <legend>Create A Poll</legend><br style="clear:both;"> <ol> <li><lable for=pollTitle>Poll Title:</lable><input name="pollTitle" id="pollTitle" type="text" size="66" /> </li> <li><lable for=question>1st Question:</lable><input name="question" id="question" type="text" size="66" /> </li> <li><lable for=answerType>Constrained:</lable><input name="answerType" id="answerType" value="Constrained" type="radio" size="66" /><span style="margin: 0 0 0 40px;"> Unconstrained: <input style="margin-right: 30px;" name="answerType" value="Unconstrained" id="question" type="radio" size="66" /></span>(Allow multiple answers) </li> <li><lable for=answer1>Answer:</lable><input name="answer1" id="answer1" type="text" size="66" /> </li> <li><lable for=answer2>Answer:</lable><input name="answer2" id="answer2" type="text" size="66" /> </li> <li><lable for=answer3>Answer:</lable><input name="answer3" id="answer3" type="text" size="66" /> </li> <li><lable for=answer4>Answer:</lable><input name="answer4" id="answer4" type="text" size="66" /> </li> </ol><br /> </fieldset> <input type="button" value="Add More Answers" name="addAnswer" onClick="generateRow()" /><input type="submit" name="submit" value="Add Another Question"> </form> And here is generateRow(): var count = 5; function generateRow() { var d=document.getElementById("contact"); var b = document.getElementById("answer4"); var c =b.name.charAt(0); var f = b.name.substr(0, 6); var y = f + count; count = count + 1; d.innerHTML+='<li><lable for=' + y + '>Answer:</lable><input name="' + y + '" id="' + y + '" type="text" size="66"/> </li>'; } The issue is whenever a new row is added, it erases any input that may have been typed in any of the un-original (added) text fields. It should leave the data in form elements

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  • Find location using only distance and range?

    - by pinnacler
    Triangulation works by checking your angle to three KNOWN targets. "I know the that's the Lighthouse of Alexandria, it's located here (X,Y) on a map, and it's to my right at 90 degrees." Repeat 2 more times for different targets and angles. Trilateration works by checking your distance from three KNOWN targets. "I know the that's the Lighthouse of Alexandria, it's located here (X,Y) on a map, and I'm 100 meters away from that." Repeat 2 more times for different targets and ranges. But both of those methods rely on knowing WHAT you're looking at. Say you're in a forest and you can't differentiate between trees, but you know where key trees are. These trees have been hand picked as "landmarks." You have a robot moving through that forest slowly. Do you know of any ways to determine location based solely off of angle and range, exploiting geometry between landmarks? Note, you will see other trees as well, so you won't know which trees are key trees. Ignore the fact that a target may be occluded. Our pre-algorithm takes care of that. 1) If this exists, what's it called? I can't find anything. 2) What do you think the odds are of having two identical location 'hits?' I imagine it's fairly rare. 3) If there are two identical location 'hits,' how can I determine my exact location after I move the robot next. (I assume the chances of having 2 occurrences of EXACT angles in a row, after I reposition the robot, would be statistically impossible, barring a forest growing in rows like corn). Would I just calculate the position again and hope for the best? Or would I somehow incorporate my previous position estimate into my next guess? If this exists, I'd like to read about it, and if not, develop it as a side project. I just don't have time to reinvent the wheel right now, nor have the time to implement this from scratch. So if it doesn't exist, I'll have to figure out another way to localize the robot since that's not the aim of this research, if it does, lets hope it's semi-easy.

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  • Another IKImageView Question: copying a region

    - by Brian Postow
    I'm trying to use the select and copy feature of the IKImageView. If all you want to do is have an app with an image, select a portion and copy it to the clipboard, it's easy. You set the copy menu pick to the first responder's copy:(id) method and magically everything works. However, if you want something more complicated, like you want to copy as part of some other operation, I can't seem to find the method to do this. IKImageView doesn't seem to have a copy method, it doesn't seem to have a method that will even tell you the selected rectangle! I have gone through Hillegass' book, so I understand how the clipboard works, just not how to get the portion of the image out of the view... Now, I'm starting to think that I made a mistake in basing my project on IKImageView, but it's what Preview is built on (or so I've read), so I figured it had to be stable... and anyway, now it's too late, I'm too deep in this to start over... So, other than not using IKImageView, any suggestions on how to copy the select region to the clipboard manually? EDIT actually, I have found the copy(id) method, but when I call it, I get <Error>: CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component; 16 bits/pixel; 1-component color space; kCGImageAlphaPremultipliedLast; 2624 bytes/row. Which obviously doesn't happen when I do a normal copy through the first-responder... I understand the error message, but I'm not sure where it's getting those parameters from... Is there any way to trace through this and see how this is happening? A debugger won't help for obvious reasons, as well as the fact that I'm doing this in Mozilla, so a debugger isn't an option anyway... EDIT 2 It occurs to me that the copy:(id) method I found may be copying the VIEW rather than copying a chunk of the image to the clipboard, which is what I need. The reason I thought it was the clipboard copy is that in another project, where I'm copying from an IKImageView to the clipboard straight from the edit menu, it just sends a copy:(id) to the firstResponder, but I'm not actually sure what the firstresponder does with it...

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  • Multiline editable textarea in SVG

    - by Timo
    I'm trying to implement multiline editable textfield in SVG. I have the following code in http://jsfiddle.net/ca4d3/ : <svg width="1000" height="1000" overflow="scroll"> <g transform="rotate(5)"> <rect width="300" height="400" fill="#22DD22" fill-opacity="0.5"/> </g> <foreignObject x="10" y="10" overflow="visible" width="10000" height="10000" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"> <p style="display:table-cell;padding:10px;border:1px solid red; background-color:white;opacity:0.5;font-family:Verdana; font-size:20px;white-space: pre; word-wrap: normal; overflow: visible; overflow-y: visible; overflow-x:visible;" contentEditable="true" xmlns="http://www.w3.org/1999/xhtml"> Write here some text. Be smart and select some word. If you wanna be really COOL, paste here something cool! </p> </foreignObject> </svg> In newest Chrome, Safari and Firefox the code works in some way, but in Opera and IE 9 not. The goal is that: 0) Works in newest Chrome, Safari, Firefox, Opera and IE and if ever possible in some pads. 1) White-spaces are preserved and text wraps only on newline char (works in Chrome, Safari and Firefox, but not in Opera and IE 9 *). 2) The textfield is editable (in the same reliable and stabile way as textareas and contenteditable p elements in html) and height and width is expanded to fit text (works in Chrome, Safari and Firefox, but not in Opera and IE 9 *). 3) Texfield can be transformed (rotated, skewed, translated) while maintaining text editability (Tested rotation, but not work in any browser *). EDIT: Foreignobject rotation works on Firefox 15.0.1, but not in Safari 5.1.7 (6534.57.2), Chrome 22.0.1229.79, Opera 12.02, IE 9. Tested on Mac OS X 10.6.8. 4) Textfield can be clipped and masked while not necessarily maintaining text editability (not yet tested). *) using above code These all can be achieved using Flash, but Flash has so severe problems that it is not suitable for my purposes (after every little change in code, all have to be compiled again using Flex, which is slow, font size has limits, tracking technique is pixeloriented, not relative to em size etc.) and there still are differences across platforms. And I want to give a try to SVG! GUESTION: Can I achieve my goals 0-4 with current SVG support in browsers? Is coming SVG 2.0 for some help in this case? EDIT: Changed display:table to display:table-cell (and added new jsfiddle), because display:table made the field to loses focus when pressed arrow-up on first text row.

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  • UINavigationBar unresponsive after canceling a UITableView search in nav controller in tab bar in a popover

    - by Mark
    Ok, this is an odd one and I can reproduce it with a new project easily. Here is the setup: I have a UISplitViewController. In the left side I have a UITabBarController. In this tab bar controller I have two UINavigationControllers. In the navigation controllers I have UITableViewControllers. These table views have search bars on them. Ok, what happens with this setup is that if I'm in portrait mode and bring up this view in the popover and I start a search in one of the table views and cancel it, the navigation bar becomes unresponsive. That is, the "back" button as well as the right side button cannot be clicked. If I do the exact same thing in landscape mode so we are not in a popover, this doesn't happen. The navigation bar stays responsive. So, the problem only seems to happen inside a popover. I've also noticed that if I do the search but click on an item in the search results which ends up loading something into the "detail view" of the split view and dismissing the popover, and then come back to the popover and then click the Cancel button for the search, the navigation bar is responsive. My application is a universal app and uses the same tab bar controller in the iPhone interface and it works there without this issue. As I mentioned above, I can easily reproduce this with a new project. Here are the steps if you want to try it out yourself: start new project - split view create new UITableViewController class (i named TableViewController) uncomment out the viewDidLoad method as well as the rightBarButtonItem line in viewDidLoad (so we will have an Edit button in the navigation bar) enter any values you want to return from numberOfSectioinsInTableView and numberOfRowsInSection methods open MainWindow.xib and do the following: please note that you will need to be viewing the xib in the middle "view mode" so you can expand the contents of the items drag a Tab Bar Controller into the xib to replace the Navigation Controller item drag a Navigation Controller into the xib as another item under the Tab Bar Controller delete the other two view controllers that are under the Tab Bar Controller (so, now our tab bar has just the one navigation controller on it) inside the navigation controller, drag in a Table View Controller and use it to replace the View Controller (Root View Controller) change the class of the new Table View Controller to the class created above (TableViewController for me) double-click on the Table View under the new Table View Controller to open it up (will be displayed in the tab bar inside the split view controller) drag a "Search Bar and Search Display" onto the table view save the xib run the project in simulator while in portrait mode, click on the Root List button to bring up popover notice the Edit button is clickable click in the Search box - we go into search mode click the Cancel button to exit search mode notice the Edit button no longer works So, can anyone help me figure out why this is happening? Thanks, Mark

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  • Jquery: How do i not select a specific colum

    - by Poku
    Hey I have a table, where i have a click event on the tr: <tr id="<%= candidate.AnsogerID %>" class="newCandidatesTableTr"> , this click event: $(".newCandidatesTableTr").click(function(e) { works just fine, but in the row i also have a click event on a td: $(".insertCandidate").live("click", (function(e) { and this conflicts eachother. I want to do one thing if the tr is clicked and other when this specific td in the tr is clicked. So how do i in my tr.click() event defined that the event shall not happend when i click the specific td? Here is the code: // Lists a table with old candidates who migth be the same person as the new candidate $(".newCandidatesTableTr").click(function(e) { alert(this.id); GetCandidateName(this.id); }); // Show insert candidate dialog $(".insertCandidate").live("click", (function(e) { var tempCanName = $(".suggentionCandidatesTableTitle").text(); var tempCanNameSub = tempCanName.substr(0, tempCanName.length - 1); var canName = $(".suggentionCandidateName_" + canID + "").text(); $("#mergeCandidateDialog").empty(); $.blockUI({ message: $("#mergeCandidateDialog").append( "<div>" + tempCanNameSub + "'s ansøgning vil blive lagt under den eksiterende ansøger " + canName + "'s data.<br /><br /> Ønsker du at fortsætte?<br /><br /></div>" + "<div id=\"content\">" + "<input type=\"button\" id=\"" + this.id + "\" class=\"insertCandidateYes\" value=\"Ja\" />" + "<input type=\"button\" id=\"insertCandidateNo\" value=\"Nej\" /></div>"), css: { cursor: 'default', fontWeight: 'normal', padding: '7px', textAlign: 'left' } }); })); <% foreach (var candidate in Model.Ansogninger) { %> <tr id="<%= candidate.AnsogerID %>" class="newCandidatesTableTr"> <td><div id="candidateID""><label title="<%= candidate.Navn %>"><%= candidate.AnsogerID %></label></div></td> <td><div id="<%= "candidateName_" + candidate.AnsogerID %>" class="candidateNameTD"><%= candidate.Navn %></div></td> <td><div id="candidateEmail"><%= candidate.Email %></div></td> <td><div id="candidateRundeName"><%= Model.RundeName %></div></td> <td id="testTD"> <div id="<%= "acceptCandidateButton_" + candidate.AnsogerID %>" class="acceptb">Godkend</div> </td> </tr> <% } %> /Thanks

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  • Advice on software / database design to avoid using cursors when updating database

    - by Remnant
    I have a database that logs when an employee has attended a course and when they are next due to attend the course (courses tend to be annual). As an example, the following employee attended course '1' on 1st Jan 2010 and, as the course is annual, is due to attend next on the 1st Jan 2011. As today is 20th May 2010 the course status reads as 'Complete' i.e. they have done the course and do not need to do it again until next year: EmployeeID CourseID AttendanceDate DueDate Status 123456 1 01/01/2010 01/01/2011 Complete In terms of the DueDate I calculate this in SQL when I update the employee's record e.g. DueDate = AttendanceDate + CourseFrequency (I pull course frequency this from a separate table). In my web based app (asp.net mvc) I pull back this data for all employees and display it in a grid like format for HR managers to review. This allows HR to work out who needs to go on courses. The issue I have is as follows. Taking the example above, suppose today is 2nd Jan 2011. In this case, employee 123456 is now overdue for the course and I would like to set the Status to Incomplete so that the HR manager can see that they need to action this i.e. get employee on the course. I could build a trigger in the database to run overnight to update the Status field for all employees based on the current date. From what I have read I would need to use cursors to loop over each row to amend the status and this is considered bad practice / inefficient or at least something to avoid if you can??? Alternatively, I could compute the Status in my C# code after I have pulled back the data from the database and before I display it on screen. The issue with this is that the Status in the database would not necessarily match what is shown on screen which just feels plain wrong to me. Does anybody have any advice on the best practice approach to such an issue? It helps, if I did use a cursor I doubt I would be looping over more than 1000 records at any given time. Maybe this is such small volume that using cursors is okay?

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  • Restoring multiple database backups in a transaction

    - by Raghu Dodda
    I wrote a stored procedure that restores as set of the database backups. It takes two parameters - a source directory and a restore directory. The procedure looks for all .bak files in the source directory (recursively) and restores all the databases. The stored procedure works as expected, but it has one issue - if I uncomment the try-catch statements, the procedure terminates with the following error: error_number = 3013 error_severity = 16 error_state = 1 error_message = DATABASE is terminating abnormally. The weird part is sometimes (it is not consistent) the restore is done even if the error occurs. The procedure: create proc usp_restore_databases ( @source_directory varchar(1000), @restore_directory varchar(1000) ) as begin declare @number_of_backup_files int -- begin transaction -- begin try -- step 0: Initial validation if(right(@source_directory, 1) <> '\') set @source_directory = @source_directory + '\' if(right(@restore_directory, 1) <> '\') set @restore_directory = @restore_directory + '\' -- step 1: Put all the backup files in the specified directory in a table -- declare @backup_files table ( file_path varchar(1000)) declare @dos_command varchar(1000) set @dos_command = 'dir ' + '"' + @source_directory + '*.bak" /s/b' /* DEBUG */ print @dos_command insert into @backup_files(file_path) exec xp_cmdshell @dos_command delete from @backup_files where file_path IS NULL select @number_of_backup_files = count(1) from @backup_files /* DEBUG */ select * from @backup_files /* DEBUG */ print @number_of_backup_files -- step 2: restore each backup file -- declare backup_file_cursor cursor for select file_path from @backup_files open backup_file_cursor declare @index int; set @index = 0 while(@index < @number_of_backup_files) begin declare @backup_file_path varchar(1000) fetch next from backup_file_cursor into @backup_file_path /* DEBUG */ print @backup_file_path -- step 2a: parse the full backup file name to get the DB file name. declare @db_name varchar(100) set @db_name = right(@backup_file_path, charindex('\', reverse(@backup_file_path)) -1) -- still has the .bak extension /* DEBUG */ print @db_name set @db_name = left(@db_name, charindex('.', @db_name) -1) /* DEBUG */ print @db_name set @db_name = lower(@db_name) /* DEBUG */ print @db_name -- step 2b: find out the logical names of the mdf and ldf files declare @mdf_logical_name varchar(100), @ldf_logical_name varchar(100) declare @backup_file_contents table ( LogicalName nvarchar(128), PhysicalName nvarchar(260), [Type] char(1), FileGroupName nvarchar(128), [Size] numeric(20,0), [MaxSize] numeric(20,0), FileID bigint, CreateLSN numeric(25,0), DropLSN numeric(25,0) NULL, UniqueID uniqueidentifier, ReadOnlyLSN numeric(25,0) NULL, ReadWriteLSN numeric(25,0) NULL, BackupSizeInBytes bigint, SourceBlockSize int, FileGroupID int, LogGroupGUID uniqueidentifier NULL, DifferentialBaseLSN numeric(25,0) NULL, DifferentialBaseGUID uniqueidentifier, IsReadOnly bit, IsPresent bit ) insert into @backup_file_contents exec ('restore filelistonly from disk=' + '''' + @backup_file_path + '''') select @mdf_logical_name = LogicalName from @backup_file_contents where [Type] = 'D' select @ldf_logical_name = LogicalName from @backup_file_contents where [Type] = 'L' /* DEBUG */ print @mdf_logical_name + ', ' + @ldf_logical_name -- step 2c: restore declare @mdf_file_name varchar(1000), @ldf_file_name varchar(1000) set @mdf_file_name = @restore_directory + @db_name + '.mdf' set @ldf_file_name = @restore_directory + @db_name + '.ldf' /* DEBUG */ print 'mdf_logical_name = ' + @mdf_logical_name + '|' + 'ldf_logical_name = ' + @ldf_logical_name + '|' + 'db_name = ' + @db_name + '|' + 'backup_file_path = ' + @backup_file_path + '|' + 'restore_directory = ' + @restore_directory + '|' + 'mdf_file_name = ' + @mdf_file_name + '|' + 'ldf_file_name = ' + @ldf_file_name restore database @db_name from disk = @backup_file_path with move @mdf_logical_name to @mdf_file_name, move @ldf_logical_name to @ldf_file_name -- step 2d: iterate set @index = @index + 1 end close backup_file_cursor deallocate backup_file_cursor -- end try -- begin catch -- print error_message() -- rollback transaction -- return -- end catch -- -- commit transaction end Does anybody have any ideas why this might be happening? Another question: is the transaction code useful ? i.e., if there are 2 databases to be restored, will SQL Server undo the restore of one database if the second restore fails?

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  • What is causing this SQL 2005 Primary Key Deadlock between two real-time bulk upserts?

    - by skimania
    Here's the scenario: I've got a table called MarketDataCurrent (MDC) that has live updating stock prices. I've got one process called 'LiveFeed' which reads prices streaming from the wire, queues up inserts, and uses a 'bulk upload to temp table then insert/update to MDC table.' (BulkUpsert) I've got another process which then reads this data, computes other data, and then saves the results back into the same table, using a similar BulkUpsert stored proc. Thirdly, there are a multitude of users running a C# Gui polling the MDC table and reading updates from it. Now, during the day when the data is changing rapidly, things run pretty smoothly, but then, after market hours, we've recently started seeing an increasing number of Deadlock exceptions coming out of the database, nowadays we see 10-20 a day. The imporant thing to note here is that these happen when the values are NOT changing. Here's all the relevant info: Table Def: CREATE TABLE [dbo].[MarketDataCurrent]( [MDID] [int] NOT NULL, [LastUpdate] [datetime] NOT NULL, [Value] [float] NOT NULL, [Source] [varchar](20) NULL, CONSTRAINT [PK_MarketDataCurrent] PRIMARY KEY CLUSTERED ( [MDID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] - stackoverflow wont let me post images until my reputation goes up to 10, so i'll add them as soon as you bump me up, hopefully as a result of this question. ![alt text][1] [1]: http://farm5.static.flickr.com/4049/4690759452_6b94ff7b34.jpg I've got a Sql Profiler Trace Running, catching the deadlocks, and here's what all the graphs look like. stackoverflow wont let me post images until my reputation goes up to 10, so i'll add them as soon as you bump me up, hopefully as a result of this question. ![alt text][2] [2]: http://farm5.static.flickr.com/4035/4690125231_78d84c9e15_b.jpg Process 258 is called the following 'BulkUpsert' stored proc, repeatedly, while 73 is calling the next one: ALTER proc [dbo].[MarketDataCurrent_BulkUpload] @updateTime datetime, @source varchar(10) as begin transaction update c with (rowlock) set LastUpdate = getdate(), Value = t.Value, Source = @source from MarketDataCurrent c INNER JOIN #MDTUP t ON c.MDID = t.mdid where c.lastUpdate < @updateTime and c.mdid not in (select mdid from MarketData where LiveFeedTicker is not null and PriceSource like 'LiveFeed.%') and c.value <> t.value insert into MarketDataCurrent with (rowlock) select MDID, getdate(), Value, @source from #MDTUP where mdid not in (select mdid from MarketDataCurrent with (nolock)) and mdid not in (select mdid from MarketData where LiveFeedTicker is not null and PriceSource like 'LiveFeed.%') commit And the other one: ALTER PROCEDURE [dbo].[MarketDataCurrent_LiveFeedUpload] AS begin transaction -- Update existing mdid UPDATE c WITH (ROWLOCK) SET LastUpdate = t.LastUpdate, Value = t.Value, Source = t.Source FROM MarketDataCurrent c INNER JOIN #TEMPTABLE2 t ON c.MDID = t.mdid; -- Insert new MDID INSERT INTO MarketDataCurrent with (ROWLOCK) SELECT * FROM #TEMPTABLE2 WHERE MDID NOT IN (SELECT MDID FROM MarketDataCurrent with (NOLOCK)) -- Clean up the temp table DELETE #TEMPTABLE2 commit To clarify, those Temp Tables are being created by the C# code on the same connection and are populated using the C# SqlBulkCopy class. To me it looks like it's deadlocking on the PK of the table, so I tried removing that PK and switching to a Unique Constraint instead but that increased the number of deadlocks 10-fold. I'm totally lost as to what to do about this situation and am open to just about any suggestion. HELP!!

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  • Hibernate save() and transaction rollback

    - by Marco
    Hi, In Hibernate when i save() an object in a transaction, and then i rollback it, the saved object still remains in the DB. It's strange because this issue doesn't happen with the update() or delete() method, just with save(). Here is the code i'm using: DbEntity dbEntity = getDbEntity(); HibernateUtil.beginTransaction(); Session session = HibernateUtil.getCurrentSession(); session.save(dbEntity); HibernateUtil.rollbackTransaction(); And here is the HibernateUtil class (just the involved functions, i guarantee the getSessionFactory() method works well - there is an Interceptor handler, but it doesn't matter now): private static final ThreadLocal<Session> threadSession = new ThreadLocal<Session>(); private static final ThreadLocal<Transaction> threadTransaction = new ThreadLocal<Transaction>(); /** * Retrieves the current Session local to the thread. * <p/> * If no Session is open, opens a new Session for the running thread. * * @return Session */ public static Session getCurrentSession() throws HibernateException { Session s = (Session) threadSession.get(); try { if (s == null) { log.debug("Opening new Session for this thread."); if (getInterceptor() != null) { log.debug("Using interceptor: " + getInterceptor().getClass()); s = getSessionFactory().openSession(getInterceptor()); } else { s = getSessionFactory().openSession(); } threadSession.set(s); } } catch (HibernateException ex) { throw new HibernateException(ex); } return s; } /** * Start a new database transaction. */ public static void beginTransaction() throws HibernateException { Transaction tx = (Transaction) threadTransaction.get(); try { if (tx == null) { log.debug("Starting new database transaction in this thread."); tx = getCurrentSession().beginTransaction(); threadTransaction.set(tx); } } catch (HibernateException ex) { throw new HibernateException(ex); } } /** * Rollback the database transaction. */ public static void rollbackTransaction() throws HibernateException { Transaction tx = (Transaction) threadTransaction.get(); try { threadTransaction.set(null); if ( tx != null && !tx.wasCommitted() && !tx.wasRolledBack() ) { log.debug("Tyring to rollback database transaction of this thread."); tx.rollback(); } } catch (HibernateException ex) { throw new HibernateException(ex); } finally { closeSession(); } } Thanks

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  • Proper way to use Linq with WPF

    - by Ingó Vals
    I'm looking for a good guide into the right method of using Linq to Sql together with WPF. Most guides only go into the bare basics like how to show data from a database but noone I found goes into how to save back to the database. Can you answer or point out to me a guide that can answer these questions. I have a separate Data project because the same data will also be used in a web page so I have the repository method. That means I have a seperate class that uses the DataContext and there are methods like GetAllCompanies() and GetCompanyById ( int id ). 1) Where there are collections is it best to return as a IQueryable or should I return a list? Inside the WPF project I have seen reccomendations to wrap the collection in a ObservabgleCollection. 2) Why should I use ObservableCollection and should I use it even with Linq / IQueryable Some properties of the linq entities should be editable in the app so I set them to two-way mode. That would change the object in the observableCollection. 3) Is the object in the ObservableCollection still a instance of the original linq entity and so is the change reflected in the database ( when submitchanges is called ) I should have somekind of save method in the repository. But when should I call it? What happens if someone edits a field but decides not to save it, goes to another object and edits it and then press save. Doesn't the original change also save? When does it not remember the changes to a linq entity object anymore. Should I instance the Datacontext class in each method so it loses scope when done. 4) When and how to call the SubmitChanges method 5) Should I have the DataContext as a member variable of the repository class or a method variable To add a new row I should create a new object in a event ( "new" button push ) and then add it to the database using a repo method. 6) When I add the object to the database there will be no new object in the ObservableCollection. Do I refresh somehow. 7) I wan't to reuse the edit window when creating new but not sure how to dynamically changing from referencing selected item from a listview to this new object. Any examples you can point out.

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  • DOM memory issue with IE8 (inserting lots of JSON data)

    - by okie.floyd
    i am developing a small web-utility that displays some data from some database tables. i have the utility running fine on FF, Safari, Chrome..., but the memory management on IE8 is horrendous. the largest JSON request I do will return information to create around 5,000 or so rows in a table within the browser (3 columns in the table). i'm using jquery to get the data (via getJSON). to remove the old/existing table, i'm just doing a $('#my_table_tbody').empty(). to add the new info to the table, within the getJSON callback, i am just appending each table row that i am creating to a variable, and then once i have them all, i am using $('#my_table_tbody').append(myVar) to add it to the existing tbody. i don't add the table rows as they are created because that seems to be a lot slower than just adding them all at once. does anyone have any recommendation on what someone should do who is trying to add thousands of rows of data to the DOM? i would like to stay away from pagination, but i'm wondering if i don't have a choice. Update 1 So here is the code I was trying after the innerHTML suggestion: /* Assuming a div called 'main_area' holds the table */ document.getElementById('main_area').innerHTML = ''; $.getJSON("my_server", {my: JSON, args: are, in: here}, function(j) { var mylength = j.length; var k =0; var tmpText = ''; tmpText += /* Add the table, thead stuff, and tbody tags here */; for (k = mylength - 1; k = 0; k--) { /* stack overflow wont let me type greater than & less than signs here, so just assume that they are there. */ tmpText += 'tr class="' + j[k].row_class . '" td class="col1_class" ' + j[k].col1 + ' /td td class="col2_class" ' + j[k].col2 + ' /td td class="col3_class" ' + j[k].col3 + ' /td /tr'; } document.getElementById('main_area').innerHTML = tmpText; } That is the gist of it. I've also tried using just a $.get request, and having the server send the formatted HTML, and just setting that in the innerHTML (i.e. document.getElementById('main_area').innerHTML = j;). thanks for all of the replies. i'm floored with the fact that you all are willing to help.

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  • ASP NET MVC (loading data from database)

    - by rah.deex
    hi experts, its me again... i have some code like this.. using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace MvcGridSample.Models { public class CustomerService { private List<SVC> Customers { get { List<SVC> customers; if (HttpContext.Current.Session["Customers"] != null) { customers = (List<SVC>) HttpContext.Current.Session["Customers"]; } else { //Create customer data store and save in session customers = new List<SVC>(); InitCustomerData(customers); HttpContext.Current.Session["Customers"] = customers; } return customers; } } public SVC GetByID(int customerID) { return this.Customers.AsQueryable().First(customer => customer.seq_ == customerID); } public IQueryable<SVC> GetQueryable() { return this.Customers.AsQueryable(); } public void Add(SVC customer) { this.Customers.Add(customer); } public void Update(SVC customer) { } public void Delete(int customerID) { this.Customers.RemoveAll(customer => customer.seq_ == customerID); } private void InitCustomerData(List<SVC> customers) { customers.Add(new SVC { ID = 1, FirstName = "John", LastName = "Doe", Phone = "1111111111", Email = "[email protected]", OrdersPlaced = 5, DateOfLastOrder = DateTime.Parse("5/3/2007") }); customers.Add(new SVC { ID = 2, FirstName = "Jane", LastName = "Doe", Phone = "2222222222", Email = "[email protected]", OrdersPlaced = 3, DateOfLastOrder = DateTime.Parse("4/5/2008") }); customers.Add(new SVC { ID = 3, FirstName = "John", LastName = "Smith", Phone = "3333333333", Email = "[email protected]", OrdersPlaced = 25, DateOfLastOrder = DateTime.Parse("4/5/2000") }); customers.Add(new SVC { ID = 4, FirstName = "Eddie", LastName = "Murphy", Phone = "4444444444", Email = "[email protected]", OrdersPlaced = 1, DateOfLastOrder = DateTime.Parse("4/5/2003") }); customers.Add(new SVC { ID = 5, FirstName = "Ziggie", LastName = "Ziggler", Phone = null, Email = "[email protected]", OrdersPlaced = 0, DateOfLastOrder = null }); customers.Add(new SVC { ID = 6, FirstName = "Michael", LastName = "J", Phone = "666666666", Email = "[email protected]", OrdersPlaced = 5, DateOfLastOrder = DateTime.Parse("12/3/2007") }); } } } those codes is an example that i've got from the internet.. in that case, the data is created and saved in session before its shown.. the things that i want to ask is how if i want to load the data from table? i'am a newbie here.. please help :) thank b4 for advance..

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  • C++ type-checking at compile-time

    - by Masterofpsi
    Hi, all. I'm pretty new to C++, and I'm writing a small library (mostly for my own projects) in C++. In the process of designing a type hierarchy, I've run into the problem of defining the assignment operator. I've taken the basic approach that was eventually reached in this article, which is that for every class MyClass in a hierarchy derived from a class Base you define two assignment operators like so: class MyClass: public Base { public: MyClass& operator =(MyClass const& rhs); virtual MyClass& operator =(Base const& rhs); }; // automatically gets defined, so we make it call the virtual function below MyClass& MyClass::operator =(MyClass const& rhs); { return (*this = static_cast<Base const&>(rhs)); } MyClass& MyClass::operator =(Base const& rhs); { assert(typeid(rhs) == typeid(*this)); // assigning to different types is a logical error MyClass const& casted_rhs = dynamic_cast<MyClass const&>(rhs); try { // allocate new variables Base::operator =(rhs); } catch(...) { // delete the allocated variables throw; } // assign to member variables } The part I'm concerned with is the assertion for type equality. Since I'm writing a library, where assertions will presumably be compiled out of the final result, this has led me to go with a scheme that looks more like this: class MyClass: public Base { public: operator =(MyClass const& rhs); // etc virtual inline MyClass& operator =(Base const& rhs) { assert(typeid(rhs) == typeid(*this)); return this->set(static_cast<Base const&>(rhs)); } private: MyClass& set(Base const& rhs); // same basic thing }; But I've been wondering if I could check the types at compile-time. I looked into Boost.TypeTraits, and I came close by doing BOOST_MPL_ASSERT((boost::is_same<BOOST_TYPEOF(*this), BOOST_TYPEOF(rhs)>));, but since rhs is declared as a reference to the parent class and not the derived class, it choked. Now that I think about it, my reasoning seems silly -- I was hoping that since the function was inline, it would be able to check the actual parameters themselves, but of course the preprocessor always gets run before the compiler. But I was wondering if anyone knew of any other way I could enforce this kind of check at compile-time.

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  • Advantage of creating a generic repository vs. specific repository for each object?

    - by LuckyLindy
    We are developing an ASP.NET MVC application, and are now building the repository/service classes. I'm wondering if there are any major advantages to creating a generic IRepository interface that all repositories implement, vs. each Repository having its own unique interface and set of methods. For example: a generic IRepository interface might look like (taken from this answer): public interface IRepository : IDisposable { T[] GetAll<T>(); T[] GetAll<T>(Expression<Func<T, bool>> filter); T GetSingle<T>(Expression<Func<T, bool>> filter); T GetSingle<T>(Expression<Func<T, bool>> filter, List<Expression<Func<T, object>>> subSelectors); void Delete<T>(T entity); void Add<T>(T entity); int SaveChanges(); DbTransaction BeginTransaction(); } Each Repository would implement this interface (e.g. CustomerRepository:IRepository, ProductRepository:IRepository, etc). The alternate that we've followed in prior projects would be: public interface IInvoiceRepository : IDisposable { EntityCollection<InvoiceEntity> GetAllInvoices(int accountId); EntityCollection<InvoiceEntity> GetAllInvoices(DateTime theDate); InvoiceEntity GetSingleInvoice(int id, bool doFetchRelated); InvoiceEntity GetSingleInvoice(DateTime invoiceDate, int accountId); //unique InvoiceEntity CreateInvoice(); InvoiceLineEntity CreateInvoiceLine(); void SaveChanges(InvoiceEntity); //handles inserts or updates void DeleteInvoice(InvoiceEntity); void DeleteInvoiceLine(InvoiceLineEntity); } In the second case, the expressions (LINQ or otherwise) would be entirely contained in the Repository implementation, whoever is implementing the service just needs to know which repository function to call. I guess I don't see the advantage of writing all the expression syntax in the service class and passing to the repository. Wouldn't this mean easy-to-messup LINQ code is being duplicated in many cases? For example, in our old invoicing system, we call InvoiceRepository.GetSingleInvoice(DateTime invoiceDate, int accountId) from a few different services (Customer, Invoice, Account, etc). That seems much cleaner than writing the following in multiple places: rep.GetSingle(x => x.AccountId = someId && x.InvoiceDate = someDate.Date); The only disadvantage I see to using the specific approach is that we could end up with many permutations of Get* functions, but this still seems preferable to pushing the expression logic up into the Service classes. What am I missing?

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  • Hibernate mapping to object that already exists

    - by teehoo
    I have two classes, ServiceType and ServiceRequest. Every ServiceRequest must specify what kind of ServiceType it is. All ServiceType's are predefined in the database, and ServiceRequest is created at runtime by the client. Here are my .hbm files: <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceRequest" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="quantity"> <column name="quantity" not-null="true"/> </property> <many-to-one cascade="all" class="xxx.model.entity.ServiceType" column="service_type" name="serviceType" not-null="false" unique="false"/> </class> </hibernate-mapping> and <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceType" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="description"> <column name="description" not-null="false"/> </property> <property name="cost"> <column name="cost" not-null="true"/> </property> <property name="enabled"> <column name="enabled" not-null="true"/> </property> </class> </hibernate-mapping> When I run this, I get com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails I think my problem is that when I create a new ServiceRequest object, ServiceType is one of its properties, and therefore when I'm saving ServiceRequest to the database, Hibernate attempts to insert the ServiceType object once again, and finds that it is already exists. If this is the case, how do I make it so that Hibernate points to the exists ServiceType instead of trying to insert it again?

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  • Understanding CLR 2.0 Memory Model

    - by Eloff
    Joe Duffy, gives 6 rules that describe the CLR 2.0+ memory model (it's actual implementation, not any ECMA standard) I'm writing down my attempt at figuring this out, mostly as a way of rubber ducking, but if I make a mistake in my logic, at least someone here will be able to catch it before it causes me grief. Rule 1: Data dependence among loads and stores is never violated. Rule 2: All stores have release semantics, i.e. no load or store may move after one. Rule 3: All volatile loads are acquire, i.e. no load or store may move before one. Rule 4: No loads and stores may ever cross a full-barrier (e.g. Thread.MemoryBarrier, lock acquire, Interlocked.Exchange, Interlocked.CompareExchange, etc.). Rule 5: Loads and stores to the heap may never be introduced. Rule 6: Loads and stores may only be deleted when coalescing adjacent loads and stores from/to the same location. I'm attempting to understand these rules. x = y y = 0 // Cannot move before the previous line according to Rule 1. x = y z = 0 // equates to this sequence of loads and stores before possible re-ordering load y store x load 0 store z Looking at this, it appears that the load 0 can be moved up to before load y, but the stores may not be re-ordered at all. Therefore, if a thread sees z == 0, then it also will see x == y. If y was volatile, then load 0 could not move before load y, otherwise it may. Volatile stores don't seem to have any special properties, no stores can be re-ordered with respect to each other (which is a very strong guarantee!) Full barriers are like a line in the sand which loads and stores can not be moved over. No idea what rule 5 means. I guess rule 6 means if you do: x = y x = z Then it is possible for the CLR to delete both the load to y and the first store to x. x = y z = y // equates to this sequence of loads and stores before possible re-ordering load y store x load y store z // could be re-ordered like this load y load y store x store z // rule 6 applied means this is possible? load y store x // but don't pop y from stack (or first duplicate item on top of stack) store z What if y was volatile? I don't see anything in the rules that prohibits the above optimization from being carried out. This does not violate double-checked locking, because the lock() between the two identical conditions prevents the loads from being moved into adjacent positions, and according to rule 6, that's the only time they can be eliminated. So I think I understand all but rule 5, here. Anyone want to enlighten me (or correct me or add something to any of the above?)

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  • Visual Studio soft-crashing when encountering XAML Errors in initialize.

    - by Aren
    I've been having some serious issues with Visual Studio 2010 as of late. It's been crashing in a peculiar way when I encounter certain types of XAML errors during the InitializeComponent() of a control/window. The program breaks and visual studio gears up like it's catching an exception (because it is) and then stops midway displaying a broken highlight in my XAML file with no details as to what is wrong. Example: There is not pop outs, or details Anywhere about what is wrong, only a callstack that points to my InitializeComponent() call. Now normally I'd just do some trial and error to fix this problem, and find out where i messed up, but the real problem isn't my code. Visual Studio is rendered completely useless at this point. It reports my application still in "Running" mode. The Stop/Break/Restart buttons on the toolbar or in the menus don't do anything (but grey out). Closing the application does not stop this behaviour, closing visual studio gets it stuck in a massive loop where it yells at me complaining every file open is not in the debug project, then repeats this process when i have exausted every open file. I have to force-close devenv.exe, and after this happening 3-4 times in a row it's a lot of wasted time (as my projects are usually pretty big and studio can be quite slow @ loading). To the point Has anyone else experienced this? How can I stop studio from locking up. Can I at LEAST get information out of this beast another way so i can fix my XAML error sooner rather than after 3-4 trial-and-error compiles yielding the same crash? Any & All help would be appreciated. Visual Studio 2010 version: 10.0.30319.1RTM Edit & Update FWIW, mostly the errors that cause this are XamlParseExceptions (I figured this out after i found what was wrong with my XAML). I think I need to be clearer though, Im not looking for the solution to my code problem, as these are usually typos / small things, I'm looking for a solution to VStudio getting all buggered up as a result. The particular error in the above image that 100% for sure caused this was a XamlParseException caused by forgetting a Value attribute on a data trigger. I've fixed that part but it still doesn't tell my why my studio becomes a lump of neutered program when a perfectly normal exception is thrown in the parsing of the XAML. Code that will cause this issue (at least for me) This is the base template WPF Application, with the following Window.xaml code. The problem is a missing Value="True" on the <DataTrigger ...> in the template. It generates a XamlParseException and Visual Studio Crashes as described above when debugging it. Final Notes The following solutions did not help me: Restarting Visual Studio Rebooting Reinstalling Visual Studio

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  • Can I create a custom class that inherits from a strongly typed DataRow?

    - by Calvin Fisher
    I'm working on a huge, old project with a lot of brittle code, some of which has been around since the .NET 1.0 era, and it has been and will be worked on by other people... so I'd like to change as little as possible. I have one project in my solution that contains DataSet.xsd. This project compiles to a separate assembly (Data.dll). The database schema includes several tables arranged more or less hierarchically, but the only way the tables are actually linked together is through joins. I can get, e.g. DepartmentRow and EmployeeRow objects from the autogenerated code. EmployeeRow contains information from the employee's corresponding DepartmentRow through a join. I'm making a new report to view multiple departments and all their employees. If I use the existing data access scheme, all I will be able to get is a spreadsheet-like output where each employee is represented on one line, with department information repeated over and over in its appropriate columns. E.g.: Department1...Employee1... Department1...Employee2... Department2...Employee3... But what the customer would like is to have each department render like a heading, with a list of employees beneath each. E.g.: - Department1... Employee1... Employee2... + Department2... I'm trying to do this by inheriting hierarchical objects from the autogenerated Row objects. E.g.: public class Department : DataSet.DepartmentRow { public List<Employee> Employees; } That way I could nest the data in the report by using a collection of Department objects as the DataSource, each of which will put its list of Employees in a subreport. The problem is that this gives me a The type Data.DataSet.DepartmentRow has no constructors defined error. And when I try to make a constructor, e.g. public class Department : DataSet.DepartmentRow { private Department() { } public List<Employee> Employees; } I get a 'Data.DataSet.DepartmentRow(System.Data.DataRowBuilder)' is inaccessible due to its protection level. error in addition to the first one. Is there a way to accomplish what I'm trying to do? Or is there something else I should be trying entirely?

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  • Find location using only distance and bearing?

    - by pinnacler
    Triangulation works by checking your angle to three KNOWN targets. "I know the that's the Lighthouse of Alexandria, it's located here (X,Y) on a map, and it's to my right at 90 degrees." Repeat 2 more times for different targets and angles. Trilateration works by checking your distance from three KNOWN targets. "I know the that's the Lighthouse of Alexandria, it's located here (X,Y) on a map, and I'm 100 meters away from that." Repeat 2 more times for different targets and ranges. But both of those methods rely on knowing WHAT you're looking at. Say you're in a forest and you can't differentiate between trees, but you know where key trees are. These trees have been hand picked as "landmarks." You have a robot moving through that forest slowly. Do you know of any ways to determine location based solely off of angle and range, exploiting geometry between landmarks? Note, you will see other trees as well, so you won't know which trees are key trees. Ignore the fact that a target may be occluded. Our pre-algorithm takes care of that. 1) If this exists, what's it called? I can't find anything. 2) What do you think the odds are of having two identical location 'hits?' I imagine it's fairly rare. 3) If there are two identical location 'hits,' how can I determine my exact location after I move the robot next. (I assume the chances of having 2 occurrences of EXACT angles in a row, after I reposition the robot, would be statistically impossible, barring a forest growing in rows like corn). Would I just calculate the position again and hope for the best? Or would I somehow incorporate my previous position estimate into my next guess? If this exists, I'd like to read about it, and if not, develop it as a side project. I just don't have time to reinvent the wheel right now, nor have the time to implement this from scratch. So if it doesn't exist, I'll have to figure out another way to localize the robot since that's not the aim of this research, if it does, lets hope it's semi-easy.

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  • Div and tr align

    - by Hulk
    All, I am adding the follwing data to a table dynamically.So when adding this how to make the following appear inline.i.e, now the text area are showing up in new lines. And the images should be appear at the right hand corner of the row. <div bgcolor="black"> <img src="close.gif"> </td></tr> <tr> <td> <div id="catgegory"> </div> <div id="description"> </div> </td> <td> <div id = "div_content_bold"> <textarea name = "point_text_81_1" rows = "8" cols = "18" class = "input" WRAP ></textarea> </div> </td> <td> <div id = "div_content_bold"> <textarea name = "point_text_81_1" rows = "8" cols = "18" class = "input" WRAP ></textarea> </div> </td> <td> <div id = "div_content_bold"> <textarea name = "point_text_81_1" rows = "8" cols = "18" class = "input" WRAP ></textarea> </div> </td> <td> <div id = "div_content_bold"> <textarea name = "point_text_81_1" rows = "8" cols = "18" class = "input" WRAP ></textarea> </div> </td> <td> </td> </tr> </div> Thanks..

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  • Unique_ptr compiler errors

    - by Godric Seer
    I am designing and entity-component system for a project, and C++ memory management is giving me a few issues. I just want to make sure my design is legitimate. So to start I have an Entity class which stores a vector of Components: class Entity { private: std::vector<std::unique_ptr<Component> > components; public: Entity() { }; void AddComponent(Component* component) { this -> components.push_back(std::unique_ptr<Component>(component)); } ~Entity(); }; Which if I am not mistaken means that when the destructor is called (even the default, compiler created one), the destructor for the Entity, will call ~components, which will call ~std::unique_ptr for each element in the vector, and lead to the destruction of each Component, which is what I want. The component class has virtual methods, but the important part is its constructor: Component::Component(Entity parent) { parent.addComponent(this) // I am not sure if this would work like I expect // Other things here } As long as passing this to the method works, this also does what I want. My confusion is in the factory. What I want to do is something along the lines of: std::shared_ptr<Entity> createEntity() { std::shared_ptr<Entity> entityPtr(new Entity()); new Component(*parent); // Initialize more, and other types of Components return entityPtr; } Now, I believe that this setup will leave the ownership of the Component in the hands of its Parent Entity, which is what I want. First a small question, do I need to pass the entity into the Component constructor by reference or pointer or something? If I understand C++, it would pass by value, which means it gets copied, and the copied entity would die at the end of the constructor. The second, and main question is that code based on this sample will not compile. The complete error is too large to print here, however I think I know somewhat of what is going on. The compiler's error says I can't delete an incomplete type. My Component class has a purely virtual destructor with an implementation: inline Component::~Component() { }; at the end of the header. However since the whole point is that Component is actually an interface. I know from here that a complete type is required for unique_ptr destruction. The question is, how do I work around this? For reference I am using gcc 4.4.6.

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  • how to pass data when using MenuItem.ItemContainerStyle

    - by black sensei
    Hello Experts! i've been trying to have a dynamic ContextMenu to show the name property of each of the object in its collection of objects. here is concrete example ,i'm connecting to a webservice to pull contacts and groups of a particular account.so i have those as global variables.i display the contacts in a listbox and i want to show on right click of a contact in the listbox the list of groups that it can be added to. to be able to add a contact to a group i need the id of the contact(which i have) and the id of the group which i'm looking for here is my code. xmlns:serviceAdmin="clr-namespace:MyWpfApp.serviceAdmin" ...... <ListBox.ContextMenu> <ContextMenu> <MenuItem Header="Refresh" Click="RefreshContact_Click"></MenuItem> <MenuItem Header="Add New Contact" Click="ContactNew_Click"></MenuItem> <MenuItem Header="Add to Group" Name="groupMenus"> //<!--<MenuItem.Resources> // <DataTemplate DataType="{x:Type serviceAdmin:groupInfo}" x:Key="groupMenuKey" > // <MenuItem> // <TextBlock Text="{Binding name}" /> // </MenuItem> // </DataTemplate> // </MenuItem.Resources>--> <MenuItem.ItemContainerStyle> <Style> <Setter Property="MenuItem.Header" Value="{Binding name}"/> <Setter Property="MenuItem.Tag" Value="{Binding id}" /> </Style> </MenuItem.ItemContainerStyle> </MenuItem> <MenuItem Header="Delete Selected" Click="ContactDelete_Click"></MenuItem> </ContextMenu> </ListBox.ContextMenu> ...... and on xaml.cs //this code is in the method that loads the groups loadedgroup = service.getGroups(session.key, null); groupListBox.ItemsSource = loadedgroup; groupMenus.ItemsSource = loadedgroup.ToList(); this code is showing the name of the groups alright but i need the id of the group clicked on. If you've noticed i commented a portion of the xaml code. with that i could bind(with ease) the id to the tag.But it won't work and the MenuItem.ItemContainerStyle is the one working but then i'm lost: Question 1 : how do i create a handler method for a click event of a submenu that has the names of the groups? Question 2 : how do i get the clicked group id to work with? thanks for reading and kindly help me in this

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  • B-trees, databases, sequential inputs, and speed.

    - by IanC
    I know from experience that b-trees have awful performance when data is added to them sequentially (regardless of the direction). However, when data is added randomly, best performance is obtained. This is easy to demonstrate with the likes of an RB-Tree. Sequential writes cause a maximum number of tree balances to be performed. I know very few databases use binary trees, but rather used n-order balanced trees. I logically assume they suffer a similar fate to binary trees when it comes to sequential inputs. This sparked my curiosity. If this is so, then one could deduce that writing sequential IDs (such as in IDENTITY(1,1)) would cause multiple re-balances of the tree to occur. I have seen many posts argue against GUIDs as "these will cause random writes". I never use GUIDs, but it struck me that this "bad" point was in fact a good point. So I decided to test it. Here is my code: SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[T1]( [ID] [int] NOT NULL CONSTRAINT [T1_1] PRIMARY KEY CLUSTERED ([ID] ASC) ) GO CREATE TABLE [dbo].[T2]( [ID] [uniqueidentifier] NOT NULL CONSTRAINT [T2_1] PRIMARY KEY CLUSTERED ([ID] ASC) ) GO declare @i int, @t1 datetime, @t2 datetime, @t3 datetime, @c char(300) set @t1 = GETDATE() set @i = 1 while @i < 2000 begin insert into T2 values (NEWID(), @c) set @i = @i + 1 end set @t2 = GETDATE() WAITFOR delay '0:0:10' set @t3 = GETDATE() set @i = 1 while @i < 2000 begin insert into T1 values (@i, @c) set @i = @i + 1 end select DATEDIFF(ms, @t1, @t2) AS [Int], DATEDIFF(ms, @t3, getdate()) AS [GUID] drop table T1 drop table T2 Note that I am not subtracting any time for the creation of the GUID nor for the considerably extra size of the row. The results on my machine were as follows: Int: 17,340 ms GUID: 6,746 ms This means that in this test, random inserts of 16 bytes was almost 3 times faster than sequential inserts of 4 bytes. Would anyone like to comment on this? Ps. I get that this isn't a question. It's an invite to discussion, and that is relevant to learning optimum programming.

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