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  • What kinds of problems are most likely to occur? (question rewritten)

    - by ChrisC
    If I wrote 1) a C# SQL db app (a simple program consisting of a gui over some forms with logic for interfacing with the sql db) 2) for home use, that doesn't do any network communication 3) that uses a simple, reliable, and appropriate sql db 4) whose gui is properly separated from the logic 5) that has complete and dependable input data validation 6) that has been completely tested so that 100% of logic bugs were eliminated ... and then if the program was installed and run by random users on their random Windows computers Q1) What types of technical (non-procedural) problems and support situations are most likely to occur, and how likely are they? Q2) Are there more/other things I could do in the first place to prevent those problems and also minimize the amount of user support required? I know some answers will apply to my specific platforms (C#, SQL, Windows, etc) and some won't. Please be as specific as is possible. Mitch Wheat gave me some very valuable advice below, but I'm now offering the bounty because I am hoping to get a better picture of the kinds of things that I'm most reasonably likely to encounter. Thanks.

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  • how do simple SQLAlchemy relationships work?

    - by Carson Myers
    I'm no database expert -- I just know the basics, really. I've picked up SQLAlchemy for a small project, and I'm using the declarative base configuration rather than the "normal" way. This way seems a lot simpler. However, while setting up my database schema, I realized I don't understand some database relationship concepts. If I had a many-to-one relationship before, for example, articles by authors (where each article could be written by only a single author), I would put an author_id field in my articles column. But SQLAlchemy has this ForeignKey object, and a relationship function with a backref kwarg, and I have no idea what any of it MEANS. I'm scared to find out what a many-to-many relationship with an intermediate table looks like (when I need additional data about each relationship). Can someone demystify this for me? Right now I'm setting up to allow openID auth for my application. So I've got this: from __init__ import Base from sqlalchemy.schema import Column from sqlalchemy.types import Integer, String class Users(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) username = Column(String, unique=True) email = Column(String) password = Column(String) salt = Column(String) class OpenID(Base): __tablename__ = 'openid' url = Column(String, primary_key=True) user_id = #? I think the ? should be replaced by Column(Integer, ForeignKey('users.id')), but I'm not sure -- and do I need to put openids = relationship("OpenID", backref="users") in the Users class? Why? What does it do? What is a backref?

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  • Getting hibernate to log clob parameters

    - by SCdF
    (see here for the problem I'm trying to solve) How do you get hibernate to log clob values it's going to insert. It is logging other value types, such as Integer etc. I have the following in my log4j config: log4j.logger.net.sf.hibernate.SQL=DEBUG log4j.logger.org.hibernate.SQL=DEBUG log4j.logger.net.sf.hibernate.type=DEBUG log4j.logger.org.hibernate.type=DEBUG Which produces output such as: (org.hibernate.SQL) insert into NoteSubstitutions (note, listIndex, substitution) values (?, ?, ?) (org.hibernate.type.LongType) binding '170650' to parameter: 1 (org.hibernate.type.IntegerType) binding '0' to parameter: 2 (org.hibernate.SQL) insert into NoteSubstitutions (note, listIndex, substitution) values (?, ?, ?) (org.hibernate.type.LongType) binding '170650' to parameter: 1 (org.hibernate.type.IntegerType) binding '1' to parameter: 2 However you'll note that it never displays parameter: 3 which is our clob. What I would really want is something like: (org.hibernate.SQL) insert into NoteSubstitutions (note, listIndex, substitution) values (?, ?, ?) (org.hibernate.type.LongType) binding '170650' to parameter: 1 (org.hibernate.type.IntegerType) binding '0' to parameter: 2 (org.hibernate.type.ClobType) binding 'something' to parameter: 3 (org.hibernate.SQL) insert into NoteSubstitutions (note, listIndex, substitution) values (?, ?, ?) (org.hibernate.type.LongType) binding '170650' to parameter: 1 (org.hibernate.type.IntegerType) binding '1' to parameter: 2 (org.hibernate.type.ClobType) binding 'something else' to parameter: 3 How do I get it to show this in the log?

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  • ProtoInclude for fields ?

    - by Big
    I have a simple object [ProtoContract] public class DataChangedEventArgs<T> : EventArgs { private readonly object key; private readonly T data; private readonly DataChangeType changeType; ///<summary> /// Key to identify the data item ///</summary> public object Key { get { return key; } } [ProtoMember(2, IsRequired = true)] public T Data { get { return data; } } [ProtoMember(3, IsRequired = true)] public DataChangeType ChangeType { get { return changeType; } } and I have a problem with the key. Its type is object, but it can be either int, long or string. I would intuitively use a ProtoInclude attribute to say "expect these types" but unfortunately they are class only attribute. Does anybody has any idea how I could work around this ? For background, the public object Key is here for historical reasons (and all over the place) so I would very much like to avoid the mother of all refactorings ;-) Any chance I could get this to Serialize, even force it to Serialize as a string ?

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  • Writing a JavaScript zip code validation function

    - by mkoryak
    I would like to write a JavaScript function that validates a zip code, by checking if the zip code actually exists. Here is a list of all zip codes: http://www.census.gov/tiger/tms/gazetteer/zips.txt (I only care about the 2nd column) This is really a compression problem. I would like to do this for fun. OK, now that's out of the way, here is a list of optimizations over a straight hashtable that I can think of, feel free to add anything I have not thought of: Break zipcode into 2 parts, first 2 digits and last 3 digits. Make a giant if-else statement first checking the first 2 digits, then checking ranges within the last 3 digits. Or, covert the zips into hex, and see if I can do the same thing using smaller groups. Find out if within the range of all valid zip codes there are more valid zip codes vs invalid zip codes. Write the above code targeting the smaller group. Break up the hash into separate files, and load them via Ajax as user types in the zipcode. So perhaps break into 2 parts, first for first 2 digits, second for last 3. Lastly, I plan to generate the JavaScript files using another program, not by hand. Edit: performance matters here. I do want to use this, if it doesn't suck. Performance of the JavaScript code execution + download time. Edit 2: JavaScript only solutions please. I don't have access to the application server, plus, that would make this into a whole other problem =)

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  • How do I assert that two arbitrary type objects are equivalent, without requiring them to be equal?

    - by Tomas Lycken
    To accomplish this (but failing to do so) I'm reflecting over properties of an expected and actual object and making sure their values are equal. This works as expected as long as their properties are single objects, i.e. not lists, arrays, IEnumerable... If the property is a list of some sort, the test fails (on the Assert.AreEqual(...) inside the for loop). public void WithCorrectModel<TModelType>(TModelType expected, string error = "") where TModelType : class { var actual = _result.ViewData.Model as TModelType; Assert.IsNotNull(actual, error); Assert.IsInstanceOfType(actual, typeof(TModelType), error); foreach (var prop in typeof(TModelType).GetProperties()) { Assert.AreEqual(prop.GetValue(expected, null), prop.GetValue(actual, null), error); } } If dealing with a list property, I would get the expected results if I instead used CollectionAssert.AreEquivalent(...) but that requires me to cast to ICollection, which in turn requries me to know the type listed, which I don't (want to). It also requires me to know which properties are list types, which I don't know how to. So, how should I assert that two objects of an arbitrary type are equivalent? Note: I specifically don't want to require them to be equal, since one comes from my tested object and one is built in my test class to have something to compare with.

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  • Return a list of important Python modules in a script?

    - by Jono Bacon
    Hi All, I am writing a program that categorizes a list of Python files by which modules they import. As such I need to scan the collection of .py files ad return a list of which modules they import. As an example, if one of the files I import has the following lines: import os import sys, gtk I would like it to return: ["os", "sys", "gtk"] I played with modulefinder and wrote: from modulefinder import ModuleFinder finder = ModuleFinder() finder.run_script('testscript.py') print 'Loaded modules:' for name, mod in finder.modules.iteritems(): print '%s ' % name, but this returns more than just the modules used in the script. As an example in a script which merely has: import os print os.getenv('USERNAME') The modules returned from the ModuleFinder script return: tokenize heapq __future__ copy_reg sre_compile _collections cStringIO _sre functools random cPickle __builtin__ subprocess cmd gc __main__ operator array select _heapq _threading_local abc _bisect posixpath _random os2emxpath tempfile errno pprint binascii token sre_constants re _abcoll collections ntpath threading opcode _struct _warnings math shlex fcntl genericpath stat string warnings UserDict inspect repr struct sys pwd imp getopt readline copy bdb types strop _functools keyword thread StringIO bisect pickle signal traceback difflib marshal linecache itertools dummy_thread posix doctest unittest time sre_parse os pdb dis ...whereas I just want it to return 'os', as that was the module used in the script. Can anyone help me achieve this?

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  • nginx error: (99: Cannot assign requested address)

    - by k-g-f
    I am running Ubuntu Hardy 8.04 and nginx 0.7.65, and when I try starting my nginx server: $ sudo /etc/init.d/nginx start I get the following error: Starting nginx: [emerg]: bind() to IP failed (99: Cannot assign requested address) where "IP" is a placeholder for my IP address. Does anybody know why that error might be happening? This is running on EC2. My nginx.conf file looks like this: user www-data www-data; worker_processes 4; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; access_log /usr/local/nginx/logs/access.log; sendfile on; tcp_nopush on; tcp_nodelay on; keepalive_timeout 3; gzip on; gzip_comp_level 2; gzip_proxied any; gzip_types text/plain text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript; include /usr/local/nginx/sites-enabled/*; } and my /usr/local/nginx/sites-enabled/example.com looks like: server { listen IP:80; server_name example.com; rewrite ^/(.*) https://example.com/$1 permanent; } server { listen IP:443 default ssl; ssl on; ssl_certificate /etc/ssl/certs/myssl.crt; ssl_certificate_key /etc/ssl/private/myssl.key; ssl_protocols SSLv3 TLSv1; ssl_ciphers ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:-LOW:-SSLv2:-EXP; server_name example.com; access_log /home/example/example.com/log/access.log; error_log /home/example/example.com/log/error.log; }

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  • jQuery Character Counter Inside Newly Created Tooltip

    - by Dodinas
    Hello all, I'm having a difficult time figuring this one out. I'm attempting to have a user open a tooltip (using jQuery qTip). What this does is create a "new" tooltip element on the page; it takes it from an existing hidden HTML div on the webpage. Once this new tooltip is created, it has a character counter that is supposed to dynamically update as the user types in the textbox (which is inside the tooltip). The "Max Length Character Counter" script can be found here. However, the "counter" portion is not working inside the newly created tooltip. Any ideas how I can bind this max length character counter to the tooltip? Here's what I'm working with so far: function load_qtip(apply_qtip_to) { $(apply_qtip_to).each(function(){ $(this).qtip({ content: $(".tooltip-contents"), //this is a DIV in the HTML show: 'click', hide: 'unfocus' }); }); } $(document).ready(function() { load_qtip(".tooltip"); $('.my_textbox').maxlength({ 'feedback' : '.my_counter' }); }); And here's what the HTML basically looks like (remember, though, this entire div is "replicated" into a new tooltip): <div class="tooltip_contents"> <form> <div class="my_counter" id="counter">55</div> <textarea class="my_textbox" maxlength="55" id="textbox"></textarea> <input type="button" value="Submit"> </form> </div> Any direction/suggestions on this would be great, as I am completely lost. Thanks very much!

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  • ClassLoader exceptions being memoized

    - by Jim
    Hello, I am writing a classloader for a long-running server instance. If a user has not yet uploaded a class definition, I through a ClassNotFoundException; seems reasonable. The problem is this: There are three classes (C1, C2, and C3). C1 depends on C2, C2 depends on C3. C1 and C2 are resolvable, C3 isn't (yet). C1 is loaded. C1 subsequently performs an action that requires C2, so C2 is loaded. C2 subsequently performs an action that requires C3, so the classloader attempts to load C3, but can't resolve it, and an exception is thrown. Now C3 is added to the classpath, and the process is restarted (starting from the originally-loaded C1). The issue is, C2 seems to remember that C3 couldn't be loaded, and doesn't bother asking the classloader to find the class... it just re-throws the memoized exception. Clearly I can't reload C1 or C2 because other classes may have linked to them (as C1 has already linked to C2). I tried throwing different types of errors, hoping the class might not memoize them. Unfortunately, no such luck. Is there a way to prevent the loaded class from binding to the exception? That is, I want the classloader to be allowed to keep trying if it didn't succeed the first time. Thanks!

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  • How to transform vertical table into horizontal table?

    - by avivo
    Hello, I have one table Person: Id Name 1 Person1 2 Person2 3 Person3 And I have its child table Profile: Id PersonId FieldName Value 1 1 Firstname Alex 2 1 Lastname Balmer 3 1 Email [email protected] 4 1 Phone +1 2 30004000 And I want to get data from these two tables in one row like this: Id Name Firstname Lastname Email Phone 1 Person1 Alex Balmer [email protected] +1 2 30004000 What is the most optimized query to get these vertical (key, value) values in one row like this? Now I have a problem that I done four joins of child table to parent table because I need to get these four fields. Some optimization is for sure possible. I would like to be able to modify this query in easy way when I add new field (key,value). What is the best way to do this? To create some StoreProcedure? I would like to have strongly types in my DB layer (C#) and using LINQ (when programming) so it means when I add some new Key, Value pair in Profile table I would like to do minimal modifications in DB and C# if possible. Actually I am trying to get some best practices in this case.

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  • Can I use my Ninject .NET project within Orchard CMS?

    - by Mattias Z
    I am creating a website using Orchard CMS and I have an external .NET project written with Ninject for dependency injection which I would like to use together with a module within Orchard CMS. I know that Orchard uses Autofac for dependency injection and this is causing me problems since I never worked with DI before. I have created a Autofac module UserModule which registers the source UserRegistrationSource and I configured Orchard to load the module like this: OrchardStarter.cs .... builder.RegisterModule(new UserModule()); .... UserModule.cs public class UserModule : Module { protected override void Load(ContainerBuilder builder) { builder.RegisterSource(new UserRegistrationSource()); base.Load(builder); } } UserRegistrationSource.cs public class UserRegistrationSource : IRegistrationSource { public bool IsAdapterForIndividualComponents { get { return false; } } public IEnumerable<IComponentRegistration> RegistrationsFor(Service service, Func<Service, IEnumerable<IComponentRegistration>> registrationAccessor) { var serviceWithType = service as IServiceWithType; if (serviceWithType == null) yield break; var serviceType = serviceWithType.ServiceType; if (!serviceType.IsInterface || !typeof(IUserServices).IsAssignableFrom(serviceType) || serviceType == typeof(IUserServices)) yield break; var registrationBuilder = ... yield return registrationBuilder.CreateRegistration(); } } But now I'm stuck... Should I somehow try to resolve the dependencies in UserRegistrationSource by getting the requested types from the Ninject container (kernel) with Autofac or is this the wrong approach? Or should the Ninject kernel do the resolves for Autofac for the external project?

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  • how to determine if a character vector is a valid numeric or integer vector

    - by Andrew Barr
    I am trying to turn a nested list structure into a dataframe. The list looks similar to the following (it is serialized data from parsed JSON read in using the httr package). myList <- list(object1 = list(w=1, x=list(y=0.1, z="cat")), object2 = list(w=2, x=list(y=0.2, z="dog"))) unlist(myList) does a great job of recursively flattening the list, and I can then use lapply to flatten all the objects nicely. flatList <- lapply(myList, FUN= function(object) {return(as.data.frame(rbind(unlist(object))))}) And finally, I can button it up using plyr::rbind.fill myDF <- do.call(plyr::rbind.fill, flatList) str(myDF) #'data.frame': 2 obs. of 3 variables: #$ w : Factor w/ 2 levels "1","2": 1 2 #$ x.y: Factor w/ 2 levels "0.1","0.2": 1 2 #$ x.z: Factor w/ 2 levels "cat","dog": 1 2 The problem is that w and x.y are now being interpreted as character vectors, which by default get parsed as factors in the dataframe. I believe that unlist() is the culprit, but I can't figure out another way to recursively flatten the list structure. A workaround would be to post-process the dataframe, and assign data types then. What is the best way to determine if a vector is a valid numeric or integer vector?

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  • Finding a MIME type for a file on windows

    - by rmeador
    Is there a way to get a file's MIME type using some system call on Windows? I'm writing an IIS extension in C++, so it must be callable from C++, and I do have access to IIS if there is some functionality exposed. Obviously, IIS itself must be able to do this, but my googling has been unable to find out how. I did find this .net related question here on SO, but that doesn't give me much hope (as neither a good solution nor a C++ solution is mentioned there). I need it so I can serve up dynamic files using the appropriate content type from my app. My plan is to first consult a list of MIME types within my app, then fall back to the system's MIME type listing (however that works; obviously it exists since it's how you associate files with programs). I only have a file extension to work with in some cases, but in other cases I may have an actual on-disk file to examine. Since these will not be user-uploaded files, I believe I can trust the extension and I'd prefer an extension-only lookup solution since it seems simpler and faster. Thanks!

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  • MS Access 2003 - Is there a way to programmatically define the data for a chart?

    - by Justin
    So I have some VBA for taking charts built with the Form's Chart Wizard, and automatically inserting it into PowerPoint Presentation slides. I use those chart-forms as sub forms within a larger forms that has parameters the user can select to determine what is on the chart. The idea is that the user can determine the parameter, build the chart to his/her liking, and click a button and have it in a ppt slide with the company's background template, blah blah blah..... So it works, though it is very bulky in terms of the amount of objects I have to use to accomplish this. I use expressions such as the following: like forms!frmMain.Month&* to get the input values into the saved queries, which was fine when i first started, but it went over so well and they want so many options, that it is driving the number of saved queries/objects up. I need several saved forms with charts because of the number of different types of charts I need to have this be able to handle. SO FINALLY TO MY QUESTION: I would much rather do all this on the fly with some VBA. I know how to insert list boxes, and text boxes on a form, and I know how to use SQL in VBA to get the values I want from tables/queries using VBA, I just don't know if there is some vba I can use to set the data values of the charts from a resulting recordset: DIM rs AS DAO.Rescordset DIM db AS DAO.Database DIM sql AS String sql = "SELECT TOP 5 Count(tblMain.TransactionID) AS Total, tblMain.Location FROM tblMain WHERE (((tblMain.Month) = """ & me.txtMonth & """ )) ORDER BY Count (tblMain.TransactionID) DESC;" set db = currentDB set rs = db.OpenRecordSet(sql) rs.movefirst some kind of cool code in here to make this recordset the data of chart in frmChart ("Chart01") thanks for your help. apologies for the length of the explanation.

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  • Qt and variadic functions

    - by Noah Roberts
    OK, before lecturing me on the use of C-style variadic functions in C++...everything else has turned out to require nothing short of rewriting the Qt MOC. What I'd like to know is whether or not you can have a "slot" in a Qt object that takes an arbitrary amount/type of arguments. The thing is that I really want to be able to generate Qt objects that have slots of an arbitrary signature. Since the MOC is incompatible with standard preprocessing and with templates, it's not possible to do so with either direct approach. I just came up with another idea: struct funky_base : QObject { Q_OBJECT funky_base(QObject * o = 0); public slots: virtual void the_slot(...) = 0; }; If this is possible then, because you can make a template that is a subclass of a QObject derived object so long as you don't declare new Qt stuff in it, I should be able to implement a derived templated type that takes the ... stuff and turns it into the appropriate, expected types. If it is, how would I connect to it? Would this work? connect(x, SIGNAL(someSignal(int)), y, SLOT(the_slot(...))); If nobody's tried anything this insane and doesn't know off hand, yes I'll eventually try it myself...but I am hoping someone already has existing knowledge I can tap before possibly wasting my time on it.

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  • Can't get syntax on to work in my gvim.

    - by user198553
    (I'm new to Linux and Vim, and I'm trying to learn Vim but I'm having some issues with it that I can't seen do fix) I'm in a Linux installation (Ubuntu 8.04) that I can't update, using Vim 7.1.138. My vim installation is in /usr/share/vim/vim71/. /home/user/ My .vimrc file is in /home/user/.vimrc, as follows: fun! MySys() return "linux" endfun set runtimepath=~/.vim,$VIMRUTNTIME source ~/.vim/.vimrc And then, in my /home/user/.vim/.vimrc: " =============== GENERAL CONFIG ============== set nocompatible syntax on " =============== ENCODING AND FILE TYPES ===== set encoding=utf8 set ffs=unix,dos,mac " =============== INDENTING =================== set ai " Automatically set the indent of a new line (local to buffer) set si " smartindent (local to buffer) " =============== FONT ======================== " Set font according to system if MySys() == "mac" set gfn=Bitstream\ Vera\ Sans\ Mono:h13 set shell=/bin/bash elseif MySys() == "windows" set gfn=Bitstream\ Vera\ Sans\ Mono:h10 elseif MySys() == "linux" set gfn=Inconsolata\ 14 set shell=/bin/bash endif " =============== COLORS ====================== colorscheme molokai " ============== PLUGINS ====================== " -------------- NERDTree --------------------- :noremap ,n :NERDTreeToggle<CR> " =============== DIRECTORIES ================= set backupdir=~/.backup/vim set directory=~/.swap/vim ...fact is the command syntax on is not working, neither in vim or gvim. And the strange thing is: If I try to set the syntax using the gvim toolbat, it works. Then, in normal mode in gvim, after activating using the toolbar, using the code :syntax off, it works, and just after doing this trying to do :syntax on doesn't work!! What's going on? Am I missing something?

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  • Modeling a Generic Relationship (expressed in C#) in a Database

    - by StevenH
    This is most likely one for all you sexy DBAs out there: How would I effieciently model a relational database whereby I have a field in an "Event" table which defines a "SportType"? This "SportsType" field can hold a link to different sports tables E.g. "FootballEvent", "RubgyEvent", "CricketEvent" and "F1 Event". Each of these Sports tables have different fields specific to that sport. My goal is to be able to genericly add sports types in the future as required, yet hold sport specific event data (fields) as part of my Event Entity. Is it possible to use an ORM such as NHibernate / Entity framework / DataObjects.NET which would reflect such a relationship? I have thrown together a quick C# example to express my intent at a higher level: public class Event<T> where T : new() { public T Fields { get; set; } public Event() { EventType = new T(); } } public class FootballEvent { public Team CompetitorA { get; set; } public Team CompetitorB { get; set; } } public class TennisEvent { public Player CompetitorA { get; set; } public Player CompetitorB { get; set; } } public class F1RacingEvent { public List<Player> Drivers { get; set; } public List<Team> Teams { get; set; } } public class Team { public IEnumerable<Player> Squad { get; set; } } public class Player { public string Name { get; set; } public DateTime DOB { get; set;} }

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  • Baffled by differences between WPF BitmapEncoders

    - by DanM
    I wrote a little utility class that saves BitmapSource objects to image files. The image files can be either bmp, jpeg, or png. Here is the code: public class BitmapProcessor { public void SaveAsBmp(BitmapSource bitmapSource, string path) { Save(bitmapSource, path, new BmpBitmapEncoder()); } public void SaveAsJpg(BitmapSource bitmapSource, string path) { Save(bitmapSource, path, new JpegBitmapEncoder()); } public void SaveAsPng(BitmapSource bitmapSource, string path) { Save(bitmapSource, path, new PngBitmapEncoder()); } private void Save(BitmapSource bitmapSource, string path, BitmapEncoder encoder) { using (var stream = new FileStream(path, FileMode.Create)) { encoder.Frames.Add(BitmapFrame.Create(bitmapSource)); encoder.Save(stream); } } } Each of the three Save methods work, but I get unexpected results with bmp and jpeg. Png is the only format that produces an exact reproduction of what I see if I show the BitmapSource on screen using a WPF Image control. Here are the results: BMP - too dark JPEG - too saturated PNG - correct Why am I getting completely different results for different file types? I should note that the BitmapSource in my example uses an alpha value of 0.1 (which is why it appears very desaturated), but it should be possible to show the resulting colors in any image format. I know if I take a screen capture using something like HyperSnap, it will look correct regardless of what file type I save to. Here's a HyperSnap screen capture saved as a bmp: As you can see, this isn't a problem, so there's definitely something strange about WPF's image encoders. Do I have a setting wrong? Am I missing something?

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  • calling template function without <>; type inference

    - by Oops
    Hi, if I have a function template with typename T, where the compiler can set the type by itself, I do not have to write the type explicitely when I call the function like: template < typename T > T min( T v1, T v2 ) { return ( v1 < v2 ) ? v1: v2; } int i1 = 1, i2 = 2; int i3 = min( i1, i2 ); //no explicit <type> but if I have a function template with two different typenames like... template < typename TOut, typename TIn > TOut round( TIn v ) { return (TOut)( v + 0.5 ); } double d = 1.54; int i = round<int>(d); //explicit <int> Is it true that I have to specify at least 1 typename, always? I assume the reason is because C++ can not distinguish functions between different return types, true? but if I use a void function and handover a reference, again I must not explicitely specify the return typename: template < typename TOut, typename TIn > void round( TOut & vret, TIn vin ) { vret = (TOut)(vin + 0.5); } double d = 1.54; int i; round(i, d); //no explicit <int> should the conclusion be to avoid functions with return and more prefer void functions that return via a reference when writing templates? Or is there a possibility to avoid explicitely writing the return type? something like "type inference" for templates... is "type inference" possible in C++0x? I hope I was not too unclear. many thanks in advance Oops

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  • Pointer Implementation Details in C

    - by Will Bickford
    I would like to know architectures which violate the assumptions I've listed below. Also I would like to know if any of the assumptions are false for all architectures (i.e. if any of them are just completely wrong). sizeof(int *) == sizeof(char *) == sizeof(void *) == sizeof(func_ptr *) The in-memory representation of all pointers for a given architecture is the same regardless of the data type pointed to. The in-memory representation of a pointer is the same as an integer of the same bit length as the architecture. Multiplication and division of pointer data types are only forbidden by the compiler. NOTE: Yes I know this is nonsensical. What I mean is - is there hardware support to forbid this incorrect usage? All pointer values can be casted to a single integer. In other words, what architectures still make use of segments and offsets? Incrementing a pointer is equivalent to adding sizeof(the pointed data type) to the memory address stored by the pointer. If p is an int32* then p+1 is equal to the memory address 4 bytes after p. I'm most used to pointers being used in a contiguous, virtual memory space. For that usage, I can generally get by thinking of them as addresses on a number line. See (http://stackoverflow.com/questions/1350471/pointer-comparison/1350488#1350488).

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  • non-copyable objects and value initialization: g++ vs msvc

    - by R Samuel Klatchko
    I'm seeing some different behavior between g++ and msvc around value initializing non-copyable objects. Consider a class that is non-copyable: class noncopyable_base { public: noncopyable_base() {} private: noncopyable_base(const noncopyable_base &); noncopyable_base &operator=(const noncopyable_base &); }; class noncopyable : private noncopyable_base { public: noncopyable() : x_(0) {} noncopyable(int x) : x_(x) {} private: int x_; }; and a template that uses value initialization so that the value will get a known value even when the type is POD: template <class T> void doit() { T t = T(); ... } and trying to use those together: doit<noncopyable>(); This works fine on msvc as of VC++ 9.0 but fails on every version of g++ I tested this with (including version 4.5.0) because the copy constructor is private. Two questions: Which behavior is standards compliant? Any suggestion of how to work around this in gcc (and to be clear, changing that to T t; is not an acceptable solution as this breaks POD types). P.S. I see the same problem with boost::noncopyable.

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  • Assign delegate event handler from dynamically added child control

    - by mickyjtwin
    I have a control that handles commenting. In this control, I have set a delegate event handler for sending an email. I then have various types of controls, e.g. blog, articles etc, each of which may or may not have the commenting control added (which is done dynamically with me not knowing the id's), i.e. the commenting control is added outside this control. Each of these controls handles it's emailing differently(hence the event). What I'm trying to determine, is how to assign the event in the parent control. At the moment, I'm having to recursively search through all the controls on the page until I find the comment control, and set it that way. Example below explains: COMMENTING CONTROL public delegate void Commenting_OnSendEmail(); public partial class Commenting : UserControl { public Commenting_OnSendEmail OnComment_SendEmail(); private void Page_Load(object sender, EventArgs e) { if(OnComment_SendEmail != null) { OnComment_SendEmail(); } } } PARENT CONTROL public partial class Blog : UserControl { private void Page_Load(object sender, EventArgs e) { Commenting comControl = (Commenting)this.FindControl<Commenting>(this); if(comControl != null) { comCtrol.OnComment_SendEmail += new Commenting_OnSendMail(Blog_Comment_OnSendEmail); } } } Is there an easier way?

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  • Programmtically choosing image conversion format to JPEG or PNG for Silverlight display

    - by Otaku
    I have a project where I need to convert a large number of image types to be displayable in a Silverlight app - TIFF, GIF, WMF, EMF, BMP, DIB, etc. I can do these conversions on the server before hydrating the Silverlight app. However, I'm not sure when I should choose to convert to which format, either JPG or PNG. Is there some kind of standard out there like TIFF should always be a JPEG and GIF should always be a PNG. Or, if a BMP is 24 bit, it should be converted to a JPEG - any lower and it can be a PNG. Or everything is a PNG and why? What I usually see or see in response to this type of question is "Well, if the picture is a photograph, go with JPEG" or "If it has straight lines, PNG is better." Unfortunately, I won't have the luxury of viewing any of the image files at all and would like just a standard way to do this via code, even if that is a zillion if/then statements. Are there any standards or best practices around this subject? P.S. Please don't move to close this subject - it actually has no duplicate on SO because I'm not looking for subjectivity.

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  • Displaying emails in a JTable (Java Swing)

    - by Paul
    Hi I'm new to all this. I have been trying to display fetched emails in a JTable using the JavaMail add-on. However when I ask the program to set the value it never does. I have been working in NetBeans if that is any help? the fetchMail class finds all may on a server. The gui class is used to display all emails in a table as well as creating mail. You will probably think that I have tried it like a bull in a china shop, I am new to Java and trying to give myself a challenge. Any help/advice would be greatly appreciated fetchMail: package mail; import java.util.; import java.io.; import java.text.DateFormat; import java.text.SimpleDateFormat; import javax.mail.; import javax.mail.internet.; import javax.mail.search.; import javax.activation.; public class fetchMail { public void fetch(String username, String pass, String search){ MessagesTableModel tableModel = new MessagesTableModel(); String complete; DateFormat df = new SimpleDateFormat("dd/MM/yyyy"); gui gui = new gui(); // SUBSTITUTE YOUR ISP's POP3 SERVER HERE!!! String host = "imap.gmail.com"; // SUBSTITUTE YOUR USERNAME AND PASSWORD TO ACCESS E-MAIL HERE!!! String user = username; String password = pass; // SUBSTITUTE YOUR SUBJECT SUBSTRING TO SEARCH HERE!!! String subjectSubstringToSearch = search; // Get a session. Use a blank Properties object. Session session = Session.getInstance(new Properties()); Properties props = System.getProperties(); props.setProperty("mail.store.protocol", "imaps"); props.setProperty("mail.imap.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); props.setProperty("mail.imap.socketFactory.fallback", "false"); try { // Get a Store object Store store = session.getStore("imaps"); store.connect(host, user, password); // Get "INBOX" Folder fldr = store.getFolder("INBOX"); fldr.open(Folder.READ_WRITE); int count = fldr.getMessageCount(); System.out.println(count + " total messages"); // Message numebers start at 1 for(int i = 1; i <= count; i++) { // Get a message by its sequence number Message m = fldr.getMessage(i); // Get some headers Date date = m.getSentDate(); int pos = i - 1; String d = df.format(date); Address [] from = m.getFrom(); String subj = m.getSubject(); String mimeType = m.getContentType(); complete = date + "\t" + from[0] + "\t" + subj + "\t" + mimeType; //tableModel.setMessages(m); gui.setDate(d, pos); // System.out.println(d + " " + i); } // Search for e-mails by some subject substring String pattern = subjectSubstringToSearch; SubjectTerm st = new SubjectTerm(pattern); // Get some message references Message [] found = fldr.search(st); System.out.println(found.length + " messages matched Subject pattern \"" + pattern + "\""); for (int i = 0; i < found.length; i++) { Message m = found[i]; // Get some headers Date date = m.getSentDate(); Address [] from = m.getFrom(); String subj = m.getSubject(); String mimeType = m.getContentType(); //System.out.println(date + "\t" + from[0] + "\t" + // subj + "\t" + mimeType); Object o = m.getContent(); if (o instanceof String) { // System.out.println("**This is a String Message**"); // System.out.println((String)o); } else if (o instanceof Multipart) { // System.out.print("**This is a Multipart Message. "); Multipart mp = (Multipart)o; int count3 = mp.getCount(); // System.out.println("It has " + count3 + // " BodyParts in it**"); for (int j = 0; j < count3; j++) { // Part are numbered starting at 0 BodyPart b = mp.getBodyPart(j); String mimeType2 = b.getContentType(); // System.out.println( "BodyPart " + (j + 1) + // " is of MimeType " + mimeType); Object o2 = b.getContent(); if (o2 instanceof String) { // System.out.println("**This is a String BodyPart**"); // System.out.println((String)o2); } else if (o2 instanceof Multipart) { // System.out.print( // "**This BodyPart is a nested Multipart. "); Multipart mp2 = (Multipart)o2; int count2 = mp2.getCount(); // System.out.println("It has " + count2 + // "further BodyParts in it**"); } else if (o2 instanceof InputStream) { // System.out.println( // "**This is an InputStream BodyPart**"); } } //End of for } else if (o instanceof InputStream) { // System.out.println("**This is an InputStream message**"); InputStream is = (InputStream)o; // Assumes character content (not binary images) int c; while ((c = is.read()) != -1) { // System.out.write(c); } } // Uncomment to set "delete" flag on the message //m.setFlag(Flags.Flag.DELETED,true); } //End of for // "true" actually deletes flagged messages from folder fldr.close(true); store.close(); } catch (MessagingException mex) { // Prints all nested (chained) exceptions as well mex.printStackTrace(); } catch (IOException ioex) { ioex.printStackTrace(); } } } gui: /* * gui.java * * Created on 13-May-2010, 18:29:30 */ package mail; import java.text.DateFormat; import java.text.FieldPosition; import java.text.ParsePosition; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Vector; import javax.mail.Address; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.ListSelectionModel; import javax.swing.event.ListSelectionEvent; import javax.swing.event.ListSelectionListener; import javax.swing.event.TableModelListener; import javax.swing.table.DefaultTableModel; import javax.swing.table.TableModel; public class gui extends javax.swing.JFrame { private MessagesTableModel tableModel; // Table listing messages. private JTable table; String date; /** Creates new form gui */ public gui() { initComponents(); } @SuppressWarnings("unchecked") private void initComponents() { recieve = new javax.swing.JButton(); jButton1 = new javax.swing.JButton(); jScrollPane1 = new javax.swing.JScrollPane(); inboxTable = new javax.swing.JTable(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); recieve.setText("Receve"); recieve.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { recieveActionPerformed(evt); } }); jButton1.setText("new"); jButton1.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { jButton1ActionPerformed(evt); } }); inboxTable.setModel(new javax.swing.table.DefaultTableModel( new Object [][] { {null, null, null}, {null, null, null}, {null, null, null}, {null, null, null} }, new String [] { "Date", "subject", "sender" } ) { Class[] types = new Class [] { java.lang.String.class, java.lang.String.class, java.lang.String.class }; public Class getColumnClass(int columnIndex) { return types [columnIndex]; } }); jScrollPane1.setViewportView(inboxTable); inboxTable.getColumnModel().getColumn(0).setResizable(false); inboxTable.getColumnModel().getColumn(1).setResizable(false); inboxTable.getColumnModel().getColumn(2).setResizable(false); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(39, 39, 39) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 558, javax.swing.GroupLayout.PREFERRED_SIZE) .addGroup(layout.createSequentialGroup() .addComponent(recieve) .addGap(18, 18, 18) .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 75, javax.swing.GroupLayout.PREFERRED_SIZE))) .addGap(73, 73, 73)) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(31, 31, 31) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) .addComponent(recieve) .addComponent(jButton1)) .addGap(18, 18, 18) .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 258, javax.swing.GroupLayout.PREFERRED_SIZE) .addContainerGap(179, Short.MAX_VALUE)) ); pack(); }// </editor-fold> private void recieveActionPerformed(java.awt.event.ActionEvent evt) { fetchMail fetch = new fetchMail(); fetch.fetch(email goes here, password goes here, search goes here); } private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) { createMail create = new createMail(); centerW center = new centerW(); //create.attVis(); center.center(create); create.setVisible(true); } public void setDate(String Date, int pos){ //pos = pos + 1; String [] s = new String [5]; s[pos] = Date; inboxTable.setValueAt(Date, pos, 0); } public String getDate(){ return date; } /** * @param args the command line arguments */ public static void main(String args[]) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { new gui().setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JTable inboxTable; private javax.swing.JButton jButton1; private javax.swing.JScrollPane jScrollPane1; private javax.swing.JButton recieve; // End of variables declaration }

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