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  • how run Access 2007 module in Vb6?

    - by Mahmoud
    I have created a module in access 2007 that will update linked tables, but I wanted to run this module from vb6. I have tried this code from Microsoft, but it didnt work. Sub AccessTest1() Dim A As Object Set A = CreateObject("Access.Application") A.Visible = False A.OpenCurrentDatabase (App.Path & "/DataBase/acc.accdb") A.DoCmd.RunMacro "RefreshLinks" End Sub What I am aiming to do, is to allow my program to update all linked tables to new links, in case the program has been used on other computer In case you want to take a look at the module program, here it is: Sub CreateLinkedJetTable() Dim cat As ADOX.Catalog Dim tbl As ADOX.Table Set cat = New ADOX.Catalog ' Open the catalog. cat.ActiveConnection = CurrentProject.Connection Set tbl = New ADOX.Table ' Create the new table. tbl.Name = "Companies" Set tbl.ParentCatalog = cat ' Set the properties to create the link. tbl.Properties("Jet OLEDB:Link Datasource") = CurrentProject.Path & "/db3.mdb" tbl.Properties("Jet OLEDB:Remote Table Name") = "Companies" tbl.Properties("Jet OLEDB:Create Link") = True ' To link a table with a database password set the Link Provider String ' tbl.Properties("Jet OLEDB:Link Provider String") = "MS Access;PWD=Admin;" ' Append the table to the tables collection. cat.Tables.Append tbl Set cat = Nothing End Sub Sub RefreshLinks() Dim cat As ADOX.Catalog Dim tbl As ADOX.Table Set cat = New ADOX.Catalog ' Open the catalog. cat.ActiveConnection = CurrentProject.Connection Set tbl = New ADOX.Table For Each tbl In cat.Tables ' Verify that the table is a linked table. If tbl.Type = "LINK" Then tbl.Properties("Jet OLEDB:Link Datasource") = CurrentProject.Path & "/db3.mdb" ' To refresh a linked table with a database password set the Link Provider String 'tbl.Properties("Jet OLEDB:Link Provider String") = "MS Access;PWD=Admin;" End If Next End Sub

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  • Make joomla blog link to inner pages(or blog roll post actual)

    - by somdow
    So i was told to create a blog for client in Joomla and, i have minimal knowledge of Joomla inner workings. I made the blog as seen here http://www.assurancepower.com/about-us/blog.html But the problem is that, the headers/titles for each story in that blog roll cant be clicked. Im wondering is there a way i can make this happen? Essentially this page is a collection of the stories and i want to be able to click on a particular one (any of them) and be taken to its inner page/full version of the story. Not exactly sure what im supposed to do/search for. Im not sure if joomla has a wordpress like functions.php or for example, is there somewhere i can instert a....maybe something like how wordpress does it with permalinks like so: <?php permalink(); ?> //title link here to the actual story. or something like <?php bloginfo('url');?>// this relative link for WP. Etc, All i want is to be able to have these titles in this story be active links to their full counterpart. Not sure what to look for/how to go about fixing this. Thanks in advanced.

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  • Protocol specification in XML

    - by Mathijs
    Is there a way to specify a packet-based protocol in XML, so (de)serialization can happen automatically? The context is as follows. I have a device that communicates through a serial port. It sends and receives a byte stream consisting of 'packets'. A packet is a collection of elementary data types and (sometimes) other packets. Some elements of packets are conditional; their inclusion depends on earlier elements. I have a C# application that communicates with this device. Naturally, I don't want to work on a byte-level throughout my application; I want to separate the protocol from my application code. Therefore I need to translate the byte stream to structures (classes). Currently I have implemented the protocol in C# by defining a class for each packet. These classes define the order and type of elements for each packet. Making class members conditional is difficult, so protocol information ends up in functions. I imagine XML that looks like this (note that my experience designing XML is limited): <packet> <field name="Author" type="int32" /> <field name="Nickname" type="bytes" size="4"> <condition type="range"> <field>Author</field> <min>3</min> <max>6</min> </condition> </field> </packet> .NET has something called a 'binary serializer', but I don't think that's what I'm looking for. Is there a way to separate protocol and code, even if packets 'include' other packets and have conditional elements?

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  • Rationale of C# iterators design (comparing to C++)

    - by macias
    I found similar topic: http://stackoverflow.com/questions/56347/iterators-in-c-stl-vs-java-is-there-a-conceptual-difference Which basically deals with Java iterator (which is similar to C#) being unable to going backward. So here I would like to focus on limits -- in C++ iterator does not know its limit, you have by yourself compare the given iterator with the limit. In C# iterator knows more -- you can tell without comparing to any external reference, if the iterator is valid or not. I prefer C++ way, because once having iterator you can set any iterator as a limit. In other words if you would like to get only few elements instead of entire collection, you don't have to alter the iterator (in C++). For me it is more "pure" (clear). But of course MS knew this and C++ while designing C#. So what are the advantages of C# way? Which approach is more powerful (which leads to more elegant functions based on iterators). What do I miss? If you have thoughts on C# vs. C++ iterators design other than their limits (boundaries), please also answer. Note: (just in case) please, keep the discussion strictly technical. No C++/C# flamewar.

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  • Understanding REST through an example

    - by grifaton
    My only real exposure to the ideas of REST has been through Ruby on Rails' RESTful routing. This has suited me well for the kind of CRUD-based applications I have built with Rails, but consequently my understanding of RESTfulness is somewhat limited. Let's say we have a finite collection of Items, each of which has a unique ID, and a number of properties, such as colour, shape, and size (which might be undefined for some Items). Items can be used by a client for a period of time, but each Item can only be used by one client at once. Access to Items is regulated by a server. Clients can request the temporary use of certain items from a server. Usually, clients will only be interested in getting access to a number of Items with particular properties, rather than getting access to specific Items. When a client requests use of a number of Items, the server responds with a list of IDs corresponding to the request, or with a response that says that the requested Items are not currently available or do not exist. A client can make the following kinds of request: Tell me how many green triangle Items there are (in total/available). Give me use of 200 large red Items. I have finished with Items 21, 23, 23. Add 100 new red square Items. Delete 50 small green Items. Modify all big yellow pentagon Items to be blue. The toy example above is like a resource allocation problem I have had to deal with recently. How should I go about thinking about it RESTfully?

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  • A generic C++ library that provides QtConcurrent functionality?

    - by Lucas
    QtConcurrent is awesome. I'll let the Qt docs speak for themselves: QtConcurrent includes functional programming style APIs for parallel list processing, including a MapReduce and FilterReduce implementation for shared-memory (non-distributed) systems, and classes for managing asynchronous computations in GUI applications. For instance, you give QtConcurrent::map() an iterable sequence and a function that accepts items of the type stored in the sequence, and that function is applied to all the items in the collection. This is done in a multi-threaded manner, with a thread pool equal to the number of logical CPU's on the system. There are plenty of other function in QtConcurrent, like filter(), filteredReduced() etc. The standard CompSci map/reduce functions and the like. I'm totally in love with this, but I'm starting work on an OSS project that will not be using the Qt framework. It's a library, and I don't want to force others to depend on such a large framework like Qt. I'm trying to keep external dependencies to a minimum (it's the decent thing to do). I'm looking for a generic C++ framework that provides me with the same/similar high-level primitives that QtConcurrent does. AFAIK boost has nothing like this (I may be wrong though). boost::thread is very low-level compared to what I'm looking for. I know C# has something very similar with their Parallel Extensions so I know this isn't a Qt-only idea. What do you suggest I use?

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  • C++: how to build my own utility library?

    - by augustin
    I am starting to be proficient enough with C++ so that I can write my own C++ based scripts (to replace bash and PHP scripts I used to write before). I find that I am starting to have a very small collection of utility functions and sub-routines that I'd like to use in several, otherwise unrelated C++ scripts. I know I am not supposed to reinvent the wheel and that I could use external libraries for some of the utilities I'm creating for myself. However, it's fun to create my own utility functions, they are perfectly tailored to the job I have in mind, and it's for me a large part of the learning process. I'll see about using more polished external libraries when I am proficient enough to work on more serious, long term projects. So, the question is: how do I manage my personal utility library in a way that the functions can be easily included in my various scripts? I am using linux/Kubuntu, vim, g++, etc. and mostly coding CLI scripts. Don't assume too much in terms of experience! ;) Links to tutorials or places where relevant topics are properly documented are welcome.

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  • Fasted way to develop data entry screens for a .NET backend ?

    - by jay23
    I am a .NET / C# back end guy. I am working on a app that will have about 200 different data entry screens. For me exposing DTO as a collection for CRUD (IUpdatable and IQueryable) is the easy part, can do it in sleep :-). What I am trying to decide is what type of front end technology will allow me to develop these data entry screens fast. They don't have to be fancy but they are not just plain grid either and on average they have about 15 form fields and some client side data validation (no db look up) Options I am looking at are Use ExtJS on the front and REST / JSON on the back. ASP.NET RIA but I do not know SL (Well XAML) Plain ASP.NET / MVC One idea I had was the DTO will contain the meta data about the form (As Attributes) and the form can be dynamically generated, but i do not want to reinvent the wheel if their is an easy way. I have looked at RAD software but all of them look at the DB and generate screens. I rather want some thing that can look at my DTO and generate screens. Jay

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  • Generics in a bidirectional association

    - by Verhoevenv
    Let's say I have two classes A and B, with B a subtype of A. This is only part of a richer type hierarchy, obviously, but I don't think that's relevant. Assume A is the root of the hierarchy. There is a collection class C that keeps track of a list of A's. However, I want to make C generic, so that it is possible to make an instance that only keeps B's and won't accept A's. class A(val c: C[A]) { c.addEntry(this) } class B(c: C[A]) extends A(c) class C[T <: A]{ val entries = new ArrayBuffer[T]() def addEntry(e: T) { entries += e } } object Generic { def main(args : Array[String]) { val c = new C[B]() new B(c) } } The code above obviously give the error 'type mismatch: found C[B], required C[A]' on the new B(c) line. I'm not sure how this can be fixed. It's not possible to make C covariant in T (like C[+T <: A]) because the ArrayBuffer is non-variantly typed in T. It's not possible to make the constructor of B require a C[B] because C can't be covariant. Am I barking up the wrong tree here? I'm a complete Scala newbie, so any ideas and tips might be helpful. Thank you! EDIT: Basically, what I'd like to have is that the compiler accepts both val c = new C[B]() new B(c) and val c = new C[A]() new B(c) but would reject val c = new C[B]() new A(c) It's probably possible to relax the typing of the ArrayBuffer in C to be A instead of T, and thus in the addEntry method as well, if that helps.

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  • IList<T> vs IEnumerable<T>. What is more efficient IList<T> or IEnumerable<T>

    - by bigb
    What is more efficient way to make methods return IList<T> or IEnumerable<T>? IEnumerable<T> it is immutable collection but IList<T> mutable and contain a lot of useful methods and properties. To cast IList<T> to IEnumerable<T> it is just reference copy: IList<T> l = new List<T>(); IEnumerable<T> e = l; To cast IEnumerable<T> to List<T> we need to iterate each element or to call ToList() method: IEnumerable<T>.ToList(); or may pass IEnumerable<T> to List<T> constructor which doing the same iteration somewhere within its constructor. List<T> l = new List<T>(e); Which cases you think is more efficient? Which you prefer more in your practice?

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  • Computer Science taxonomy

    - by Bakhtiyor
    I am developing web application where users have collection of tags. I need to create a suggestion list for users based on the similarity of their tags. For example, when a user logs in to the system, system gets his tags and search these tags in the DB of users and showing users who have similar tags. For instance if User 1 has following tags [Linux, Apache, MySQL, PHP] and User 2 has [Windows, IIS, PHP, MySQL] it says that User 2 matchs User 1 with a weight of 50%, because he has 2 similar tags(PHP and MySQL). But imagine the situation where User 1 has [ASP, IIS, MS Access] and User 2 has [PHP, Apache, MySQL]. In this situation my system doesn't suggest User 2 as a "friend" to User 1 or vice versa. But we now that these two users has similarity on the the field of work, both works on Web Technology (or Web Programming, etc). So, that is why I need kind of taxonomy of computer science (right now, but probably I would need taxonomy of other fields also, like medicine, physics, mathematics, etc.) where these concepts are categorized and so that when I search for similarity of ASP and PHP, for example, it can say that they have similarity and belong into one group(or category). I hope I described my problem clearly, but if something wrong explained would be happy for your corrections. Thanks

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  • How can one enforce calling a base class function after derived class constructor?

    - by Mike Elkins
    I'm looking for a clean C++ idiom for the following situation: class SomeLibraryClass { public: SomeLibraryClass() { /* start initialization */ } void addFoo() { /* we are a collection of foos */ } void funcToCallAfterAllAddFoos() { /* Making sure this is called is the issue */ } }; class SomeUserClass : public SomeLibraryClass { public: SomeUserClass() { addFoo(); addFoo(); addFoo(); // SomeUserClass has three foos. } }; class SomeUserDerrivedClass : public SomeUserClass { public: SomeUserDerrivedClass() { addFoo(); // This one has four foos. } }; So, what I really want is for SomeLibraryClass to enforce the calling of funcToCallAfterAllAddFoos at the end of the construction process. The user can't put it at the end of SomeUserClass::SomeUserClass(), that would mess up SomeUserDerrivedClass. If he puts it at the end of SomeUserDerrivedClass, then it never gets called for SomeUserClass. To further clarify what I need, imagine that /* start initialization */ acquires a lock, and funcToCallAfterAllAddFoos() releases a lock. The compiler knows when all the initializations for an object are done, but can I get at that information by some nice trick?

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  • Accessing and manipulating lwpf listbox datatemplate elements

    - by black sensei
    Hello good people , i'm trying to achieve a functionality but i'm don't know how to start it. I'm using vs 2008 sp1 and i'm consuming a webservice which returns a collection (is contactInfo[]) that i bind to a ListBox with little datatemplate on it. <ListBox Margin="-146,-124,-143,-118.808" Name="contactListBox" MaxHeight="240" MaxWidth="300" MinHeight="240" MinWidth="300"> <ListBox.ItemTemplate> <DataTemplate> <TextBlock> <CheckBox Name="contactsCheck" Uid="{Binding fullName}" Checked="contacts_Checked" /><Label Content="{Binding fullName}" FontSize="15" FontWeight="Bold"/> <LineBreak/> <Label Content="{Binding mobile}" FontSize="10" FontStyle="Italic" Foreground="DimGray" /> <Label Content="{Binding email}" FontStyle="Italic" FontSize="10" Foreground="DimGray"/> </TextBlock> </DataTemplate> </ListBox.ItemTemplate> </ListBox> Every works fine so far. so When a checkbox is checked i'll like to access the information of the labels (either the) belonging to the same row or attached to it and append the information to a global variable for example (for each checkbox checked). My problem right now is that i don't know how to do that. Can any one shed some light on how to do that? if you notice Checked="contacts_Checked" that's where i planned to perform the operations. thanks for reading and helping out

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  • Risky Business with LINQ to SQL and OR Designer?

    - by Toadmyster
    I have two tables with a one to many relationship in SQL 2008. The first table (BBD) PK | BBDataID | int       | Floor_Qty | tinyint       | Construct_Year | char(4)       | etc, etc describes the data common to all buildings and the second (BBDCerts) PK | BBDCertsID | int       | BBDataID | int       | Certification_Type | varchar(20)       | etc, etc is a collection of certifications for a particular building. Thus, the primary key in BBD (BBDataID) is mapped to the corresponding field in BBDCerts via an FK relationship, but BBDCertsID is the second table's primary key and BBDataID is not because it will not be unique. My problem is that I want to be able to use the OR generated data context to get at the list of certs when I access a particular record in the BBD table. For instance: Dim vals = (From q in db.BBD Where q.BBDataID = x Select q.Floor_Qty, q.Construct_Year, q.BBDCerts).SingleOrDefault and later be able to access a particular certification like this: vals.BBDCerts.Certification_Type.First Now, the automatic associations created when the SQL tables are dropped on the design surface don't generate the EntityRef associations that are needed to access the other table using the dot notation. So, I have to use the OR designer to make the BBDCerts BBDataID a primary key (this doesn't affect the actual database), and then manually change the association properties to the appropriate OneToMany settings. There might be a better way to approach this solution but my question is, is the way I've done it safe? I've done a barrage of tests and the correct cert is referenced or updated every time. Frankly, the whole thing makes me nervous.

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  • WCF operationcontract with List type unavailable in (Silverlight) client

    - by Dave
    This is the first time I have tried returning a List of data to a Silverlight client, so I'm having trouble getting the client to recognize this operationcontract. All others are fine. I have a method on the server called ReadOwFileData that needs to return a List. ReadOwFileDataCompletedEventArgs shows up in the Object Browser in the client, but not ReadOwFileDataAsync. What I want is similar to the tutorial here. The Dictionary collection type on the client is set to System.Collections.Generic.List. I tried deleting and recreating the service reference. Web.Config on the server is using basicHttpBinding. Here is the operationcontract on the server: [OperationContract] public List<OwFileData> ReadOwFileData(string OrderID) { DataClasses1DataContext db = new DataClasses1DataContext(); var dFileData = (from p in db.OwFileDatas where p.OrderID == OrderID select p).ToList(); List<OwFileData> x = new List<OwFileData>(dFileData); return x; } Incidently, this works fine: [OperationContract] public Customer GetShippingAndContactInfo(string login, string ordernum) { DataClasses1DataContext db = new DataClasses1DataContext(); Customer dInfo = (from p in db.Customers where p.Login == login select p).Single(); return dInfo; } I would like to read this data in the client and place it into an object I created called ObservableCollection. But that obviously can't happen until the client can see the method on the server. I do not know if this is an acceptable start, but this is what is on the client so far. The ReadOwFileDataAsync object is null: void populatefilesReceivedDataSource(string OrderID) { ArtUpload.ServiceReference1.UploadServiceClient client = new ArtUpload.ServiceReference1.UploadServiceClient(); var myList = client.ReadOwFileDataAsync(OrderID); // can I just itterate thru the list instead of 'binding' }

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  • How can I filter then modify e-mails using IMAP?

    - by swolff1978
    I have asked this question in a different post here on SO: How can a read receipt be suppressed? I have been doing some research of my own to try and solve this problem and accessing the e-mail account via IMAP seems like it is going to be a good solution. I have successfully been able to access my own Inbox and mark messages as read with no issue. I have been asked to preform the same task on an Inbox that contains over 23,000 emails. I would like to run the test on a small amount of e-mails from that inbox before letting the whole 23,000 get it. Here is the code I have been running via telnet: . LOGIN [email protected] password . SELECT Inbox . STORE 1:* flags \Seen 'this line marks all the e-mails as read So my question is how can i execute that store command on a specific group of e-mails... say emails that are going to / coming from a specific account? Is there a way to like concatenate the commands? like a FETCH then the STORE? Or is there a better way to go about getting a collection of e-mails based on certain criteria and then modifying ONLY those e-mails that can be accomplished through IMAP?

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  • Complicated .NET factory design

    - by Tom W
    Hello SO; I'm planning to ask a fairly elaborate question that is also something of a musing here, so bear with me... I'm trying to design a factory implementation for a simulation application. The simulation will consist of different sorts of entities i.e. it is not a homogenous simulation in any respect. As a result, there will be numerous very different concrete implementations and only the very general properties will be abstracted at the top level. What I'd like to be able to do is create new simulation entities by calling a method on the model with a series of named arguments representing the parameters of the entity, and have the model infer what type of object is being described by the inbound parameters (from the names of the parameters and potentially the sequence they occur in) and call a factory method on the appropriate derived class. For example, if I pass the model a pair of parameters (Param1=5000, Param2="Bacon") I would like it to infer that the names Param1 and Param2 'belong' to the class "Blob1" and call a shared function "getBlob1" with named parameters Param1:=5000, Param2:="Bacon" whereas if I pass the model (Param1=5000, Param3=50) it would call a similar factory method for Blob2; because Param1 and Param3 in that order 'belong' to Blob2. I foresee several issues to resolve: Whether or not I can reflect on the available types with string parameter names and how to do this if it's possible Whether or not there's a neat way of doing the appropriate constructor inference from the combinatoric properties of the argument list or whether I'm going to have to bodge something to do it 'by hand'. If possible I'd like the model class to be able to accept parameters as parameters rather than as some collection of keys and values, which would require the model to expose a large number of parametrised methods at runtime without me having to code them explicitly - presumably one for every factory method available in the relevant namespace. What I'm really asking is how you'd go about implementing such a system, rather than whether or not it's fundamentally possible. I don't have the foresight or experience with .NET reflection to be able to figure out a way by myself. Hopefully this will prove an informative discussion.

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  • C# generics with MVVM, pulling the T out of <T>

    - by bufferz
    My Model is a generic class that contains a (for example) Value property which can be int, float, string, bool, etc. So naturally this class is represented something like Model<T>. For the sake of collections Model<T> implements the interface IModel, although IModel is itself empty of any content. My ViewModel contains and instance of Model<T> and it is passed in through ViewModel's constructor. I still want to know what T is in ViewModel, so when I expose Model to the View I know the datatype of Model's buried Value property. The class for ViewModel ends up looking like the following: class ViewModel<T> { private Model<T> _model; public ViewModel(Model<T> model) { ....blah.... } public T ModelsValue {get; set; } } This works fine, but is limited. So now I need to expose a collection of IModels with varying Ts to my View, so I'm trying to set up an ObservableCollection of new ViewModel<T>s to a changing list of IModels. The problem is, I can't figure out how to get T from Model<T> from IModel to construct ViewModel<T>(Model<T>) at runtime. In the VS2010 debugger I can mouseover any IModel object and see its full Model<int> for example at runtime so I know the data is in there. Any ideas?

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  • Vertical line on HxW canvas of pixels

    - by bobby williams
    I searched and found nothing. I'm trying to draw lines (simple y=mx+b ones) on a canvas of black pixels. It works fine, but no line occurs when it is vertical. I'm not sure why. My first if statement checks if the denominator is zero, therefore m is undefined and no need for a line equation. My second and third if statement check how steep it is and based on that, calculate the points in between. I don't think there is a need for other classes, since I think there is a bug in my code or I'm just not translating the mathematics into code properly. If more is needed, I'll be happy to post more. /** * Returns an collection of points that connects p1 and p2 */ public ArrayList getPoints() { ArrayList points = new ArrayList(); // checks to see if denominator in m is zero. if zero, undefined. if ((p2.getX() - p1.getX()) == 0) { for (int y = p1.getY(); y<p2.getY(); y++) { points.add(new Point(p1.getX(), y, getColor())); } } double m = (double)(p2.getY()-p1.getY())/(double)(p2.getX()-p1.getX()); int b = (int)(p1.getY() - (m * p1.getX())); // checks to see if slope is steep. if (m > -1 || m < 1) { for (int x = p1.getX(); x<p2.getX(); x++) { int y = (int) ((m*x)+b); points.add(new Point(x, y, getColor())); } } // checks to see if slope is not steep. if (m <= -1 || m >= 1) { for (int y = p1.getY(); y<p2.getY(); y++) { int x = (int) ((y-b)/m); points.add(new Point(x, y, getColor())); } } return points; }

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  • Firing PropertyChanged event in a complex, nested type in WPF

    - by John
    Hey I have a question about the PropertyChanged vent firing in WPF whne it is used in a complex type. I have a class called DataStore and a list of Departments (an ObservableCollection), and each department again has a list of Products. Properties in the Product class that are changed also affect properties in the Department and DataStore class. How does each Product notify the Department it belongs to, and the DataStore (which is the mother class of all) that one or more of its properties have changed their values? Example: a product has a property NumberSoldToday and is bound. The Department has a property called TotalNumberOfProductsSold: public int TotalNumberOfProductsSold { get { int result = 0; foreach(Product p in this.products) result += p.NumberSoldToday; return result; } } And the data store has a property TotalProductsSold (for all departments): public int TotalProductsSold { get { int result = 0; foreach(Product p in this.deparments) result += p.TotalNumberOfProductsSold; return result; } } If all these properties are bound, and the innermost property changes, it must somehow notify that the value of the other 2 changed as well. How? The only way I can see this happening is to hook up the PropertyChanged event in each class. Th event must also fire when deleting, adding to the collection of products and deparments, respectively. Is there a better, more clever way to do this?

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  • scala 2.8 CanBuildFrom

    - by oxbow_lakes
    Following on from another question I asked, I wanted to understand a bit more about the Scala method TraversableLike[A].map whose signature is as follows: def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That Notice a few things about this method: it takes a function turning each A in the traversable into a B it returns That and takes an implicit argument of type CanBuildFrom[Repr, B, That] I can call this as follows: > val s: Set[Int] = List("Paris", "London").map(_.length) s: Set[Int] Set(5,6) What I cannot quite grasp is how the fact that That is bound to B (i.e. it is some collection of B's) is being enforced by the compiler. The type parameters look to be independent in both the signature above and in the signature of the trait CanBuildFrom itself: trait CanBuildFrom[-From, -Elem, +To] How is the scala compiler ensuring that That cannot be forced into something which does not make sense? > val s: Set[String] = List("Paris", "London").map(_.length) //will not compile EDIT - this question of course boils down to: How does the compiler decide what implicit CanBuildFrom objects are in scope for the call?

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  • Extensions methods and forward compatibilty of source code.

    - by TcKs
    Hi, I would like solve the problem (now hypothetical but propably real in future) of using extension methods and maginification of class interface in future development. Example: /* the code written in 17. March 2010 */ public class MySpecialList : IList<MySpecialClass> { // ... implementation } // ... somewhere elsewhere ... MySpecialList list = GetMySpecialList(); // returns list of special classes var reversedList = list.Reverse().ToList(); // .Reverse() is extension method /* now the "list" is unchanged and "reveresedList" has same items in reversed order */ /* --- in future the interface of MySpecialList will be changed because of reason XYZ*/ /* the code written in some future */ public class MySpecialList : IList<MySpecialClass> { // ... implementation public MySpecialList Reverse() { // reverse order of items in this collection return this; } } // ... somewhere elsewhere ... MySpecialList list = GetMySpecialList(); // returns list of special classes var reversedList = list.Reverse().ToList(); // .Reverse() was extension method but now is instance method and do something else ! /* now the "list" is reversed order of items and "reveresedList" has same items lake in "list" */ My question is: Is there some way how to prevent this case (I didn't find them)? If is now way how to prevent it, is there some way how to find possible issues like this? If is now way how to find possible issues, should I forbid usage of extension methods? Thanks.

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  • LINQ - Splitting up a string with maximum length, but not chopping words apart.

    - by Stacey
    I have a simple LINQ Extension Method... public static IEnumerable<string> SplitOnLength(this string input, int length) { int index = 0; while (index < input.Length) { if (index + length < input.Length) yield return input.Substring(index, length); else yield return input.Substring(index); index += length; } } This takes a string, and it chops it up into a collection of strings that do not exceed the given length. This works well - however I'd like to go further. It chops words in half. I don't need it to understand anything complicated, I just want it to be able to chop a string off 'early' if cutting it at the length would be cutting in the middle of text (basically anything that isn't whitespace). However I suck at LINQ, so I was wondering if anyone had an idea on how to go about this. I know what I am trying to do, but I'm not sure how to approach it. So let's say I have the following text. This is a sample block of text that I would pass through the string splitter. I call this method SplitOnLength(6) I would get the following. This i s a sa mple b lock o f text that I would pass t hrough the s tring splitt er. I would rather it be smart enough to stop and look more like .. This is a sample // bad example, since the single word exceeds maximum length, but the length would be larger numbers in real scenarios, closer to 200. Can anyone help me?

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  • Caching vector addition over changing collections

    - by DRMacIver
    I have the following setup: I have a largish number of uuids (currently about 10k but expected to grow unboundedly - they're user IDs) and a function f : id - sparse vector with 32-bit integer values (no need to worry about precision). The function is reasonably expensive (not outrageously so, but probably on the order of a few 100ms for a given id). The dimension of the sparse vectors should be assumed to be infinite, as new dimensions can appear over time, but in practice is unlikely to ever exceed about 20k (and individual results of f are unlikely to have more than a few hundred non-zero values). I want to support the following operations efficiently: add a new ID to the collection invalidate an existing ID retrieve sum f(id) in O(changes since last retrieval) i.e. I want to cache the sum of the vectors in a way that's reasonable to do incrementally. One option would be to support a remove ID operation and treat invalidation as a remove followed by an add. The problem with this is that it requires us to keep track of all the old values of f, which is expensive in space. I potentially need to use many instances of this sort of cached structure, so I would like to avoid that. The likely usage pattern is that new IDs are added at a fairly continuous rate and are frequently invalidated at first. Ids which have been invalidated recently are much more likely to be invalidated again than ones which have remained valid for a long time, but in principle an old Id can still be invalidated. Ideally I don't want to do this in memory (or at least I want a way that lets me save the result to disk efficiently), so an idea which lets me piggyback off an existing DB implementation of some sort would be especially appreciated.

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  • Bind two images together to be dragged

    - by Ryan Beaulieu
    I'm looking for some help with a script to drag two images together at once. I currently have a script that allows me to drag thumbnail images into a collection bin to be saved later. However, some of my thumbnails have an image positioned over the top of them to represent these thumbnail images as "unknown" plants. I was wondering if someone could point me in the right direction as to how I would go about binding these two images together to be dragged. Here is my code: $(document).ready(function() { var limit = 16; var counter = 0; $("#mainBin1, #mainBin2, #mainBin3, #mainBin4, #mainBin5, #bin_One_Hd, #bin_Two_Hd, #bin_Three_Hd, #bin_Four_Hd, #bin_Five_Hd").droppable({ accept: ".selector, .plant_Unknown", drop: function(event, ui) { counter++; if (counter == limit) { $(this).droppable("disable"); } $(this).append($(ui.draggable).clone()); $("#cbOptions").show(); $(".item").draggable({ containment: "parent", grid: [72,72], }); } }); $(".selector").draggable({ helper: "clone", revert: "invalid", revertDuration: 700, opacity: 0.75, }); $(".plant_Unknown").draggable({ helper: "clone", revert: "invalid", revertDuration: 700, opacity: 0.75, }); }); Any help would be greatly appreciated. Thanks. EDIT: Website

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