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  • Two-phase lookup: can I avoid "code bloat"?

    - by Pietro
    Two-phase lookup question: Is there a more synthetic way to write this code, i.e. avoiding all those "using" directives? I tried with "using CBase<T>;", but it is not accepted. #include <iostream> template <typename T> class CBase { protected: int a, b, c, d; // many more... public: CBase() { a = 123; } }; template <typename T> class CDer : public CBase<T> { // using CBase<T>; // error, but this is what I would like using CBase<T>::a; using CBase<T>::b; using CBase<T>::c; //... public: CDer() { std::cout << a; } }; int main() { CDer<int> cd; } In my real code there are many more member variables/functions, and I was wondering if it is possible to write shorter code in some way. Of course, using the CBase::a syntax does not solve the problem... Thank's! gcc 4.1 MacOS X 10.6

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  • Unity to dispose of object

    - by Johan Levin
    Is there a way to make Unit dispose property-injected objects as part of the Teardown? The background is that I am working on an application that uses ASP.NET MVC 2, Unity and WCF. We have written our own MVC controller factory that uses unity to instantiate the controller and WCF proxies are injected using the [Dependency] attribute on public properties of the controller. At the end of the page life cycle the ReleaseController method of the controller factory is called and we call IUnityContainer.Teardown(theMvcController). At that point the controller is disposed as expected but I also need to dispose the injected wcf-proxies. (Actually I need to call Close and/or Abort on them and not Dispose but that is a later problem.) I could of course override the controllers' Dispose methods and clean up the proxies there, but I don't want the controllers to have to know about the lifecycles of the injected interfaces or even that they refer to WCF proxies. If I need to write code myself for this - what would be the best extension point? I'd appreciate any pointer.

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  • one page filter results in new page in javascript

    - by Jake
    I have links set up on one page and the relationship between the links is a parent child relationship. (For example: Parent: All, Children: Software; Hardware) These links of course lead the user to a new page that shows the results from a table that is populated. Currently these links are all Similar destinations, but just a filter in the url. But the problem is that there is a javascript filter on the page that gives the user to choose between All, Software, or Hardware. Understand basically that if the url is still reading that there on the software page but they just filtered on the page to be Hardware that doesn't look good IMO. So what I was trying to do was make the links on the inital page all go the the exact same destination and somehow still know on the new page which link was clicked and run the javascript filter from knowing which link was clicked on that page. Is there a way to found that out from javascript? I guess a way to pass that value to the new page and retrieving it in javascript without showing it in the url so I can filter the table for the user based on that value?

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  • Self-referencing tables in Linq2Sql

    - by J-Man
    Hi, I've seen a lot of questions on self-referencing tables in Linq2Sql and how to eagerly load all child records for a particular root object. I've implemented a temporary solution by accessing all underlying properties, but you can see that this doesn't do the performance any good. The thing is though, that all records are correlated with each-other using a correlation GUID. Example below: RootElement - Id: 1 - ParentId: null - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 2 - ParentId: 1 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement2 - Id: 3 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 4 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD In my case, I do have access to the correlationId, so I can retrieve all of my records by performing the following query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' select element; But, of course, I want these elements associated with each other by executing this query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' && element.ParentId == null select element; My question is: is it possible to combine the results the first query as some sort of 'caching mechanism' for the query where I get the root element? Thanks for the input. J.

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  • How to deal with multiple sub-type of one super-type in Django admin

    - by Henri
    What would be the best solution for adding/editing multiple sub-types. E.g a super-type class Contact with sub-type class Client and sub-type class Supplier. The way shown here works, but when you edit a Contact you get both inlines i.e. sub-type Client AND sub-type Supplier. So even if you only want to add a Client you also get the fields for Supplier of vice versa. If you add a third sub-type , you get three sub-type field groups, while you actually only want one sub-type group, in the mentioned example: Client. E.g.: class Contact(models.Model): contact_name = models.CharField(max_length=128) class Client(models.Model): contact = models.OneToOneField(Contact, primary_key=True) user_name = models.CharField(max_length=128) class Supplier(models.Model): contact.OneToOneField(Contact, primary_key=True) company_name = models.CharField(max_length=128) and in admin.py class ClientInline(admin.StackedInline): model = Client class SupplierInline(admin.StackedInline): model = Supplier class ContactAdmin(admin.ModelAdmin): inlines = (ClientInline, SupplierInline,) class ClientAdmin(admin.ModelAdmin): ... class SupplierAdmin(admin.ModelAdmin): ... Now when I want to add a Client, i.e. only a Client I edit Contact and I get the inlines for both Client and Supplier. And of course the same for Supplier. Is there a way to avoid this? When I want to add/edit a Client that I only see the Inline for Client and when I want to add/edit a Supplier that I only see the Inline for Supplier, when adding/editing a Contact? Or perhaps there is a different approach. Any help or suggestion will be greatly appreciated.

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  • ActionScript 3.0: placing code on stage/MC timelines a la AS2 instead of in classes

    - by BoltClock
    I'm aware that ActionScript 3.0 is designed from the ground up to be a largely object-oriented language and using it means less or even no timeline code in Flash documents. I'm quite experienced with OOP and am comfortable writing classes. However, since I mostly use Flash for animations, I hardly ever need to write ActionScript code other than for preloaders, subtitles, quality controls, website links and so on. In fact, I still set my Flash movies to use AS2 to this day because I'm used to gotoAndPlay()/gotoAndStop(), AS2 preloaders, subtitles, quality controls and even getURL(). Of course, I really want to move on now that practically everyone's on Flash Player 9 or 10 and now that I've dabbled with other OO languages like Java, C# and Objective-C too. I'm a complete newcomer to AS3 and am not very learned with AS2 either. Considering my current use of ActionScript, are there any cases where it's still OK to use very simple AS3 code in the timeline instead of moving code to a class, especially since moving to a class might mean unnecessarily increasing the number of LOC from 4 to 40? (Heck, is the latter case ('instead of ...') even a valid concern at all?)

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  • php - correct search expression for bbpress

    - by billn
    I have a very purdy styled search box in my wordpress install, and looking for continuity I want the same for my bbpress forum - currently I'm failing. For WP I have: <div id="search"> <form action="<?php bloginfo('home') ?>" method="get"> <div class="hiddenFields"></div> <p><input name="s" id="s" maxlength="100" size="18" /><input class="submit" id="submit-button" type="submit" value="submit" /></p></form> </div> For bbPress The form 'method="get"' gets kicked out and of-course I need another expression. bbpress generally seems to use: <div class="search"><?php search_form(); ?></div> This wrecks everything - I get no styling attributes at all other than position... I can make it look fine (and consistent) with by removing the - but then it's obviously just a dummy with no search - any ideas to fix the latter? Thanks <div id="search"> <div class="hiddenFields"></div> <p><input name="s" id="s" maxlength="100" size="18" /><input class="submit" id="submit-button" type="submit" value="submit" /></p> </div>

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  • Is there a way to do 'correct' arithmetical rounding in .NET? / C#

    - by Markus
    I'm trying to round a number to it's first decimal place and, considering the different MidpointRounding options, that seems to work well. A problem arises though when that number has sunsequent decimal places that would arithmetically affect the rounding. An example: With 0.1, 0.11..0.19 and 0.141..0.44 it works: Math.Round(0.1, 1) == 0.1 Math.Round(0.11, 1) == 0.1 Math.Round(0.14, 1) == 0.1 Math.Round(0.15, 1) == 0.2 Math.Round(0.141, 1) == 0.1 But with 0.141..0.149 it always returns 0.1, although 0.146..0.149 should round to 0.2: Math.Round(0.145, 1, MidpointRounding.AwayFromZero) == 0.1 Math.Round(0.146, 1, MidpointRounding.AwayFromZero) == 0.1 Math.Round(0.146, 1, MidpointRounding.ToEven) == 0.1 Math.Round(0.146M, 1, MidpointRounding.ToEven) == 0.1M Math.Round(0.146M, 1, MidpointRounding.AwayFromZero) == 0.1M I tried to come up with a function that addresses this problem, and it works well for this case, but of course it glamorously fails if you try to round i.e. 0.144449 to it's first decimal digit (which should be 0.2, but results 0.1.) (That doesn't work with Math.Round() either.) private double round(double value, int digit) { // basically the old "add 0.5, then truncate to integer" trick double fix = 0.5D/( Math.Pow(10D, digit+1) )*( value = 0 ? 1D : -1D ); double fixedValue = value + fix; // 'truncate to integer' - shift left, round, shift right return Math.Round(fixedValue * Math.Pow(10D, digit)) / Math.Pow(10D, digit); } I assume a solution would be to enumerate all digits, find the first value larger than 4 and then round up, or else round down. Problem 1: That seems idiotic, Problem 2: I have no idea how to enumerate the digits without a gazillion of multiplications and subtractios. Long story short: What is the best way to do that?

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  • Why does my adorner not re-render when the element it's applied to changes?

    - by Robert Rossney
    In a UI I'm building, I want to adorn a panel whenever one of the controls in the panel has the focus. So I handle the IsKeyboardFocusWithinChanged event, and add an adorner to the element when it gains the focus and remove the adorner when it loses focus. This seems to work OK. The problem I'm having is that the adorner isn't getting re-rendered if the bounds of the adorned element changes. For instance, in this simple case: <WrapPanel Orientation="Horizontal" IsKeyboardFocusChanged="Panel_IsKeyboardFocusChanged"> <Label>Caption</Label> <TextBox>Data</TextBox> </WrapPanel> the adorner correctly decorates the bounds of the WrapPanel when the TextBox receives the focus, but as I type in text, the TextBox expands underneath the edge of the adorner. Of course as soon as I do anything that forces the adorner to render, like ALT-TAB out of the application or give another panel the focus, it corrects itself. But how can I get it to re-render when the bounds of the adorned element change?

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  • Yet Another crosdomain.xml question or: "How to interpret documentation correctly"

    - by cboese
    Hi! I have read a lot about the new policy-policy of flash player and also know the master policy file. Now image the following situation: There are two servers with services (http) running at custom ports servera.com:2222/websiteA serverb.com:3333/websiteB Now I open a swf from server a (eg. servera.com:2222/websiteA/A.swf) that wants to access the service of serverb. Of course I need a crossdomain.xml at the right place and there are multiple variations possible. I dont want to use a master policy file, as I might not have control over the root of both servers. One solution I found works with the following crossdomain: <?xml version="1.0"?> <cross-domain-policy> <allow-access-from domain="*"/> </cross-domain-policy> served at serverb.com:3333/websiteB/crossdomain.xml So now for my question: Is it possible to get rid of the "*" and use a proper (not as general as *) domainname in the allow-access-from rule? All my attempts failed, and from what I understand it should be possible.

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  • Need to format character precedence in Strings.

    - by Christian
    I'm currently writing a Roman Numeral Converter for the fun of it. The problem works up to the aforementioned character precedence. Since Roman Numerals are not positional, i.e. III does not symbolize 1*whatever base^2 + 1*whatever base^1 + 1*whatever base^0. That of course makes it hard when somebody types in XIV and I need to make sure that the I is not added in this case, but rather subtracted. I'm not sure how to do this. What would be the best approach to tackle this? I have both the Roman Symbols and their respective decimal numbers stored in arrays: const char cRomanArray[] = "IVXLCDM"; const int romanArray[] = { 1, 5, 10, 50, 100, 500, 1000 }; so it wouldn't be too hard for me to brute-force the damn thing by simply checking the precedence within the array, i.e. if the symbol is smaller than the next symbol, i.e. in the exampe 'XIV' if 'I' is smaller than 'V', in which case it would be because I have ordered them in the array, then I could make it subtract the value instead of add. But this seems like a very ugly solution. Are there perhaps any better ones? I was thinking something along the lines of Regular Expressions maybe( forgive me if that sounds like a horrible idea, I haven't used RegExp yet, but it sounds like it could do what I need, and that's to determine the characters in a string.)

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  • Get directory path by fd

    - by tylerl
    I've run into the need to be able refer to a directory by path given its file descriptor in Linux. The path doesn't have to be canonical, it just has to be functional so that I can pass it to other functions. So, taking the same parameters as passed to a function like fstatat(), I need to be able to call a function like getxattr() which doesn't have a f-XYZ-at() variant. So far I've come up with these solutions; though none are particularly elegant. The simplest solution is to avoid the problem by calling openat() and then using a function like fgetxattr(). This works, but not in every situation. So another method is needed to fill the gaps. The next solution involves looking up the information in proc: if (!access("/proc/self/fd",X_OK)) { sprintf(path,"/proc/self/fd/%i/",fd); } This, of course, totally breaks on systems without proc, including some chroot environments. The last option, a more portable but potentially-race-condition-prone solution, looks like this: DIR* save = opendir("."); fchdir(fd); getcwd(path,PATH_MAX); fchdir(dirfd(save)); closedir(save); The obvious problem here is that in a multithreaded app, changing the working directory around could have side effects. However, the fact that it works is compelling: if I can get the path of a directory by calling fchdir() followed by getcwd(), why shouldn't I be able to just get the information directly: fgetcwd() or something. Clearly the kernel is tracking the necessary information. So how do I get to it?

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  • How can I get this dynamic WHERE statement in my LINQ-to-XML to work?

    - by Edward Tanguay
    In this question Jon Skeet offered a very interesting solution to making a LINQ-to-XML statement dynamic, but my knowledge of lambdas and delegates is not yet advanced enough to implement it: I've got it this far, but of course I get the error "smartForm does not exist in the current context": private void LoadWithId(int id) { XDocument xmlDoc = null; try { xmlDoc = XDocument.Load(FullXmlDataStorePathAndFileName); } catch (Exception ex) { throw new Exception(String.Format("Cannot load XML file: {0}", ex.Message)); } Func<XElement, bool> whereClause = (int)smartForm.Element("id") == id"; var smartForms = xmlDoc.Descendants("smartForm") .Where(whereClause) .Select(smartForm => new SmartForm { Id = (int)smartForm.Element("id"), WhenCreated = (DateTime)smartForm.Element("whenCreated"), ItemOwner = smartForm.Element("itemOwner").Value, PublishStatus = smartForm.Element("publishStatus").Value, CorrectionOfId = (int)smartForm.Element("correctionOfId"), IdCode = smartForm.Element("idCode").Value, Title = smartForm.Element("title").Value, Description = smartForm.Element("description").Value, LabelWidth = (int)smartForm.Element("labelWidth") }); foreach (SmartForm smartForm in smartForms) { _collection.Add(smartForm); } } Ideally I want to be able to just say: var smartForms = GetSmartForms(smartForm=> (int) smartForm.Element("DisplayOrder").Value > 50); I've got it this far, but I'm just not grokking the lambda magic, how do I do this? public List<SmartForm> GetSmartForms(XDocument xmlDoc, XElement whereClause) { var smartForms = xmlDoc.Descendants("smartForm") .Where(whereClause) .Select(smartForm => new SmartForm { Id = (int)smartForm.Element("id"), WhenCreated = (DateTime)smartForm.Element("whenCreated"), ItemOwner = smartForm.Element("itemOwner").Value, PublishStatus = smartForm.Element("publishStatus").Value, CorrectionOfId = (int)smartForm.Element("correctionOfId"), IdCode = smartForm.Element("idCode").Value, Title = smartForm.Element("title").Value, Description = smartForm.Element("description").Value, LabelWidth = (int)smartForm.Element("labelWidth") }); }

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  • Capturing Set Behavior with Mutating Elements

    - by Carl
    Using the Guava library, I have the following situation: SetMultimap<ImmutableFoo, Set<Foo>> setMM = HashMultimap.create(); Set<Foo> mask = Sets.newHashSet(); // ... some iteration construct { setMM.put(ImmutableFoo1, Sets.difference(SomeSetFoo1,mask)); setMM.put(ImmutableFoo1, Sets.difference(SomeSetFoo2,mask)); mask.add(someFoo); } that is, the same iteration to create the setMM is also used to create the mask - this can of course result in changes to hashCode()s and create duplicates within the SetMultimap backing. Ideally, I'd like the duplicates to drop without me having to make it happen, and avoid repeating the iteration to separately construct the multimap and mask. Any easy libraries/Set implementations to make that happen? Alternatively, can you identify a better way to drop the duplicates than: for (ImmutableFoo f : setMM.keySet()) setMM.putAll(f,setMM.removeAll(f)); revisiting the elements is probably not a performance problem, since I could combine a separate filter operation that needs to visit all the elements anyway.

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  • how to push different local git branches to heroku/master

    - by lsiden
    Heroku has a policy of ignoring all branches but 'master'. While I'm sure Heroku's designers have excellent reasons for for this policy (I'm guessing for storage and performance optimization), the consequence to me as a developer is that whatever local topic branch I may be working on, I would like an easy way to switch Heroku's master to that local topic branch and do a "git push heroku -f" to over-write master on Heroku. What I got from reading the "Pushing Refspecs" section of http://progit.org/book/ch9-5.html is git push -f heroku local-topic-branch:refs/heads/master What I'd really like is a way to set this up in the config file so that "git push heroku" always does the above, replacing local-topic-branch with the name of whatever my current branch happens to be. If anyone knows how to accomplish that, please let me know! The caveat for this, of course, is that this is only sensible if I am the only one who can push to that Heroku app/repository. A test or QA team might manage such a repository to try out different candidate branches, but they would have to coordinate so that they all agree on what branch they are pushing to it on any given day. Needless to say, it would also be a very good idea to have a separate remote repository (like Github) without this restriction for backing everything up to. I'd call that one "origin" and use "heroku" for Heroku so that "git push" always backs up everything to origin, and "git push heroku" pushes whatever branch I'm currently on to Heroku's master branch, overwriting it if necessary. Can anybody tell me if this would work? [remote "heroku"] url = [email protected]:my-app.git push = +refs/heads/*:refs/heads/master I'd like to hear from someone more experienced before I begin to experiment, although I suppose I could create a dummy app on Heroku and experiment with that. As for fetching, I don't really care if the Heroku repository is write-only. I still have a separate repository, like Github, for backup and cloning of all my work. Footnote: This question is similar to, but not quite the same as http://stackoverflow.com/questions/1489393/good-git-deployment-using-branches-strategy-with-heroku

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  • Programmatically modifying a file on Windows Server 2008 (Web Ed.)

    - by Tom
    I have written a .NET 2008 application, incorporating Microsoft.Office.Interop.Excel, that modifies an existing Excel 2007 spreadsheet. It works perfectly on my WinXP development computer. When I upload the app to a Microsoft Web Server 2008, it opens the file and reads from the file, but when the app tries to save the file, it throws this exception: "System.Runtime.InteropServices.COMException (0x800A03EC): 'july2009.xlsx' is read-only. To save a copy, click OK, then give the workbook a new name in the Save As dialog box." The file is NOT read-only, nor is it opened by any other user or app. The app and the Excel file both reside on the D: (data-only) drive. My first instinct was to look at file permissions. When nothing else worked, I literally created a temporary Group, added EVERY user and security entity to it and granted the group full control of the entire D: drive. No luck. Then I tried manually elevating the permission by running my app as administrator. No luck. Finally, I copied the file to my XP development computer and ran the app there. Of course it worked perfectly. Can anyone please tell me how to give my program permission to edit a file on Server 2008? Thanks!

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  • Overwriting lines in file in C

    - by KáGé
    Hi, I'm doing a project on filesystems on a university operating systems course, my C program should simulate a simple filesystem in a human-readable file, so the file should be based on lines, a line will be a "sector". I've learned, that lines must be of the same length to be overwritten, so I'll pad them with ascii zeroes till the end of the line and leave a certain amount of lines of ascii zeroes that can be filled later. Now I'm making a test program to see if it works like I want it to, but it doesnt. The critical part of my code: file = fopen("irasproba_tesztfajl.txt", "r+"); //it is previously loaded with 10 copies of the line I'll print later in reverse order /* this finds the 3rd line */ int count = 0; //how much have we gone yet? char c; while(count != 2) { if((c = fgetc(file)) == '\n') count++; } fflush(file); fprintf(file, "- . , M N B V C X Y Í U Á É L K J H G F D S A Ú O P O I U Z T R E W Q Ó Ü Ö 9 8 7 6 5 4 3 2 1 0\n"); fflush(file); fclose(file); Now it does nothing, the file stays the same. What could be the problem? Thank you.

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  • Creating a DataTable by filtering another DataTable

    - by Jeff Dege
    I'm working on a system that currently has a fairly complicated function that returns a DataTable, which it then binds to a GUI control on a ASP.NET WebForm. My problem is that I need to filter the data returned - some of the data that is being returned should not be displayed to the user. I'm aware of DataTable.select(), but that's not really what I need. First, it returns an array of DataRows, and I need a DataTable, so I can databind it to the GUI control. But more importantly, the filtering I need to do isn't something that can be easily put into a simple expression. I have an array of the elements which I do not want displayed, and I need to compare each element from the DataTable against that array. What I could do, of course, is to create a new DataTable, reading everything out of the original, adding to the new what is appropriate, then databinding the new to the GUI control. But that just seems wrong, somehow. In this case, the number of elements in the original DataTable aren't likely to be enough that copying them all in memory is going to cause too much trouble, but I'm wondering if there is another way. Does the .NET DataTable have functionality that would allow me to filter via a callback function?

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  • are there code signing certificates cheaper than US $99 per year? [closed]

    - by gerryLowry
    ksoftware discounts Commodo code signing certificates to US $99 per year. in the past, I've seen Commodo code signing certificates for US $80. I'm excluding CAcert which AFAIK are FREE but are not covered by browsers like IE AFAIK. QUESTION: What is the best price per year for a code signing certificate? Thank you ~~ gerry (lowry) Edit: **THIS SHOULD NOT HAVE BEEN CLOSED** from the FAQ: http://stackoverflow.com/faq ---------------------------- What kind of questions can I ask here? Programming questions, of course! As long as your question is: * detailed and specific <====== YES! * written clearly and simply <====== YES! * of interest to other programmers <====== YES! I've been programming for over 40 years. http://gerrylowryprogrammer.com/ I've taught computer programming at the community college level. I'm a Star level contributer to forums.asp.net. http://forums.asp.net/members/gerrylowry.aspx imo, I've a very good idea what is of interest to other programmers. MORE INFORMATION Ensuring the integrity of code and executables that one distributes is just as much about programming as is knowing how to flip bits in assembler, use delegates in c#, and use the BDD context/specification still of "test first testing".

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  • Not possible to load DropDownList on FormView from code behind??

    - by tbone
    I have a UserControl, containing a FormView, containing a DropDownList. The FormView is bound to a data control. Like so: <asp:FormView ID="frmEdit" DataKeyNames="MetricCode" runat="server" DefaultMode="Edit" DataSourceID="llbDataSource" Cellpadding="0" > <EditItemTemplate> <asp:DropDownList ID="ParentMetricCode" runat="server" SelectedValue='<%# Bind("ParentMetricCode") %>' /> etc, etc I am trying to populate the DropDownList from the codebehind. If this was not contained in a FormView, I would normally just do it in the Page_Load event. However, that does not work within a FormView, as as soon as I try to do it, accessing the dropdownlist in code, ie: theListcontrol = CType(formView.FindControl(listControlName), System.Web.UI.WebControls.ListControl) ...the data binding mechansim of the FormView is invoked, which, of course, tries to bind the DropDownList to the underlying datasource, causing a *'ParentMetricCode' has a SelectedValue which is invalid because it does not exist in the list of items. Parameter name: value * error, since the DropDownList has not yet been populated. I tried performing the load in the DataBinding() event of the FormView, but then: theListcontrol = CType(formView.FindControl(listControlName), System.Web.UI.WebControls.ListControl) ...fails, as the FormView.Controls.Count = 0 at that point. Is this impossible? (I do not want to have to use a secondary ObjectDataSource to bind the dropdownlist to)

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  • How do I create and use a junction table in Rails?

    - by Thierry Lam
    I have the following data: A post called Hello has categories greet Another post called Hola has categories greet, international My schema is: create_table "posts", :force => true do |t| t.string "name" t.datetime "created_at" t.datetime "updated_at" end create_table "categories", :force => true do |t| t.string "name" t.datetime "created_at" t.datetime "updated_at" end create_table "posts_categories", :force => true do |t| t.integer "post_id" t.integer "category_id" t.datetime "created_at" t.datetime "updated_at" end After reading the Rails guide, the most suitable relationship for the above seems to be: class Post < ActiveRecord::Base has_and_belongs_to_many :categories end class Category < ActiveRecord::Base has_and_belongs_to_many :posts end My junction table also seems to have a primary key. I think I need to get rid of it. What's the initial migration command to generate a junction table in Rails? What's the best course of action, should I drop posts_categories and re-create it or just drop the primary key column? Does the junction table have a corresponding model? I have used scaffold to generate the junction table code, should I get rid of the extra code? Assuming all the above has been fixed and is working properly, how do I query all posts and display them along with their named categories in the view. For example: Post #1 - hello, categories: greet Post #2 - hola, categories: greet, international

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  • SQL: Speed Improvement - Cluttered union query

    - by vol7ron
    SELECT * FROM ( SELECT a.user_id, a.f_name, a.l_name, b.user_id, b.f_name, b.l_name FROM current_tbl a INNER JOIN import_tbl b ON ( a.user_id = b.user_id ) UNION SELECT a.user_id, a.f_name, a.l_name, b.user_id, b.f_name, b.l_name FROM current_tbl a INNER JOIN import_tbl b ON ( lower(a.f_name)=lower(b.f_name) AND lower(a.l_name)=lower(b.l_name) ) ) foo -- UNION -- SELECT a.user_id , a.f_name , a.l_name , '' , '' , '' FROM current_tbl a WHERE a.user_id NOT IN ( select user_id from( SELECT a.user_id, a.f_name, a.l_name, b.user_id, b.f_name, b.l_name FROM current_tbl a INNER JOIN import_tbl b ON ( a.user_id = b.user_id ) UNION SELECT a.user_id, a.f_name, a.l_name, b.user_id, b.f_name, b.l_name FROM current_tbl a INNER JOIN import_tbl b ON ( lower(a.f_name)=lower(b.f_name) AND lower(a.l_name)=lower(b.l_name) ) ) bar ) ORDER BY user_id Example of table population: current_tbl: ------------------------------- user_id | f_name | l_name ---------+----------+---------- A1 | Adam | Acorn A2 | Beth | Berry A3 | Calv | Chard | | import_tbl: ------------------------------- user_id | f_name | l_name ---------+----------+---------- A1 | Adam | Acorn A2 | Beth | Butcher <- last_name different | | Expected Output: ----------------------------------------------------------------------- user_id1 | f_name1 | l_name1 | user_id2 | f_name2 | l_name2 ----------+-----------+-----------+------------+-----------+----------- A1 | Adam | Acorn | A1 | Adam | Acorn A2 | Beth | Berry | A2 | Beth | Butcher A3 | Calv | Chard | | | Doing this method gets rid of conditions where the row would be: A2 | Beth | Berry | A2 | Beth | Butcher But it keeps the A3 row I hope this makes sense and I haven't overly simplified it. This is a continuation question from my other question. The succession of these improvements has dropped the query down from ~32000ms to where it's at now ~1200ms - quite an improvement. I supect I can optimize by using UNION ALL in the subquery and of course the usual index optimizations, but I'm looking for the best SQL optimization. FYI this particular case is for PostgreSQL.

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  • How can I display multiple django modelformset forms in a grouped fieldsets?

    - by JT
    I have a problem with needing to provide multiple model backed forms on the same page. I understand how to do this with single forms, i.e. just create both the forms call them something different then use the appropriate names in the template. Now how exactly do you expand that solution to work with modelformsets? The wrinkle, of course, is that each 'form' must be rendered together in the appropriate fieldset. For example I want my template to produce something like this: <fieldset> <label for="id_base-0-desc">Home Base Description:</label> <input id="id_base-0-desc" type="text" name="base-0-desc" maxlength="100" /> <label for="id_likes-0-icecream">Want ice cream?</label> <input type="checkbox" name="likes-0-icecream" id="id_likes-0-icecream" /> </fieldset> <fieldset> <label for="id_base-1-desc">Home Base Description:</label> <input id="id_base-1-desc" type="text" name="base-1-desc" maxlength="100" /> <label for="id_likes-1-icecream">Want ice cream?</label> <input type="checkbox" name="likes-1-icecream" id="id_likes-1-icecream" /> </fieldset> I am using a loop like this to process the results (after form validation) base_models = base_formset.save(commit=False) like_models = like_formset.save(commit=False) for base_model, likes_model in map(None, base_models, likes_models): which works as I'd expect (I'm using map because the # of forms can be different). The problem is that I can't figure out a way to do the same thing with the templating engine. The system does work if I layout all the base models together then all the likes models after wards, but it doesn't meet the layout requirements. EDIT: Updated the problem statement to be more clear about what exactly I'm processing (I'm processing models not forms in the for loop)

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  • what's an effective way to build a csproj file in C#?

    - by jcollum
    I'd like to avoid a command line for this. I've been using the MSBuild API ( Microsoft.Build.Framework and Microsoft.Build.BuildEngine) with code that looks like this: this.buildEngine = new Engine(); BuildPropertyGroup props = new BuildPropertyGroup(); props.SetProperty("Configuration", "Debug"); this.buildEngine.RegisterLogger(this.logger); Project proj = new Project(this.buildEngine); proj.LoadXml(this.projectFileAndPath, ProjectLoadSettings.None); this.buildEngine.BuildProject(proj, "Build"); However I've run into enough problems that I can't find answers for that I'm really wondering if I'm doing this right. First, I can't find the output (there's no bin directory in any of the places where I figured the dll's would end up). Second, I tried building a project that I had made in VS2008 and the line proj.LoadXml( fails for invalid xml encoding. But of course the xml file is valid, since VS2008 can build it (I checked). At this point I'm beginning to wonder if I've picked up some code that's way out of date or a methodology that's been superseded by something else. Opinions?

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  • Should I learn VB.NET or C#?

    - by Ravi
    Background I have decided to do my graduation project (yet to start) in .NET. Regarding it, I am bit confused about: what language should I learn: VB.NET or C#? What I have learnt from those who know it that both VB.NET and C# have: The same concepts VB.NET is simpler as it is more like English statements but also C# is simple too if you already know C (Which I do know) Question So considering some factors, e.g. career point of view, newness, challenging and beneficial, etc., what language should I choose? Please help me out. And clearly do justify your answer (whatever reason you have.) References (Extra) A little information about what project I am doing: It is a database file system. Technologies I'll be using are SQL Server, WPF, etc. I just love the concept of Database file system.So those who want to know more about Database file system, here are the links DBFS (This one is really good.Serves as primary reference for me) Towards A Single Folder Filesystem stackoverflow-What is a database file system? UPDATE1 : After some really good explained answers (actually all are good at their place), I have finally decided to go with C# for myself. Thank you all. Still, you are requested to put your opinion (Once it is reopened,of course) UPDATE2 : Question reopened and made community wiki.Thank you all.

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