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• c# wpf command pattern

  - by evan

  I have a wpf gui which displays a list of information in separate window and in a separate thread from the main application. As the user performs actions in the main window the side window is updated. (For example if you clicked page down in the main window a listbox in the side window would page down). Right now the architecture for this application feels very messy and I'm sure there is a cleaner way to do it. It looks like this: Main Window contains a singleton SideWindowControl which communicates with an instance of the SideWindowDisplay using events - so, for example, the pagedown button would work like: 1) the event handler of the button on the main window calls SideWindowControl.PageDown() 2) in the PageDown() function a event is created and thrown. 3) finally the gui, ShowSideWindowDisplay is subscribing to the SideWindowControl.Actions event handles the event and actually scrolls the listbox down - note because it is in a different thread it has to do that by running the command via Dispatcher.Invoke() This just seems like a very messy way to this and there must be a clearer way (The only part that can't change is that the main window and the side window must be on different threads). Perhaps using WPF commands? I'd really appreciate any suggestions!! Thanks

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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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• Using an embedded DB (SQLite / SQL Compact) for Message Passing within an app?

  - by wk1989

  Hello, Just out of curiosity, for applications that have a fairly complicated module tree, would something like sqlite/sql compact edition work well for message passing? So if I have modules containing data such as: \SubsystemA\SubSubSysB\ModuleB\ModuleDataC, \SubSystemB\SubSubSystemC\ModuleA\ModuleDataX Using traditional message passing/routing, you have to go through intermediate modules in order to pass a message to ModuleB to request say ModuleDataC. Instead of doing that, if we we simply store "\SubsystemA\SubSubSysB\ModuleB\ModuleDataC" in a sqlite database, getting that data is as simple as a sql query and needs no routing and passing stuff around. Has anyone done this before? Even if you haven't, do you foresee any issues & performance impact? The only concern I have right now would be the passing of custom types, e.g. if ModuleDataC is a custom data structure or a pointer, I'll need some way of storing the data structure into the DB or storing the pointer into the DB. Thanks, JW EDIT One usage case I haven't thought about is when you want to send a message from ModuleA to ModuleB to get ModuleB to do something rather than just getting/setting data. Is it possible to do this using an embedded DB? I believe callback from the DB would be needed, how feasible is this?

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• Tools and environments supporting Domain Driven Design (DDD)

  - by anthares

  Hi everyone, I'm doing a kind of research on the topic "Domain Driven Design". My question is what tools (or maybe environments) do you use, that support this paradigm? I know that I can google it, but I wonder which of them actually work and are useful, since I have no experience with neither of them. I'm interesting mainly in the .NET Framework, but any other opinions are also welcome! Thanks !

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• good c++ documentation design example?

  - by Eye of Hell

  Hello. I'm tuning documentation generator for internal purpose that generates HTML documentation for C++ classes and methods. Is it any example available of good HTML documentation design? MSDN ( like this ) looks kinda outdated, same is doxygen / javadoc / sphinx results. Anyone ever see an documentation that looks REALLY good?

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• How to properly dispose of an object

  - by VoodooChild

  Hi Guys, I am experiencing something weird and have a workaround already, but I don't think I understood it well. If I call the Method below numerous times within a class: public void Method() { Foo a = new Foo(); a.Delegate1Handler = ViewSomething(); } So I am reinitializing "a" every time but for some reason a.Delegate1Handler is still around from the previous initialization, and therefore ViewSomething() is called again and again and again.... I feel like I am forgetting something critical here? Foo's guts look like: public delegate void Delegate1(T t); public Delegate1 Delegate1Handler { get; set; }

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• LINQ to SQL - Lightweight O/RM?

  - by CoffeeAddict

  I've heard from some that LINQ to SQL is good for lightweight apps. But then I see LINQ to SQL being used for Stackoverflow, and a bunch of other .coms I know (from interviewing with them). Ok, so is this true? for an e-commerce site that's bringing in millions and you're typically only doing basic CRUDs most the time with the exception of an occasional stored proc for something more complex, is LINQ to SQL complete enough and performance-wise good enough or able to be tweaked enough to run happily on an e-commerce site? I've heard that you just need to tweak performance on the DB side when using LINQ to SQL for a better approach. So there are really 2 questions here: 1) Meaning/scope/definition of a "Lightweight" O/RM solution: What the heck does "lightweight" mean when people say LINQ to SQL is a "lightweight O/RM" and is that true??? If this is so lightweight then why do I see a bunch of huge .coms using it? Is it good enough to run major .coms (obviously it looks like it is) and what determines what the context of "lightweight" is...it's such a generic statement. 2) Performance: I'm working on my own .com and researching different O/RMs. I'm not really looking at the Entity Framework (yet), just want to figure out the LINQ to SQL basics here and determine if it will be efficient enough for me. The problem I think is you can't tweak or control the SQL it generates...

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• Passing arguments between classes - use public properties or pass a properties class as argument?

  - by devoured elysium

  So let's assume I have a class named ABC that will have a list of Point objects. I need to make some drawing logic with them. Each one of those Point objects will have a Draw() method that will be called by the ABC class. The Draw() method code will need info from ABC class. I can only see two ways to make them have this info: Having Abc class make public some properties that would allow draw() to make its decisions. Having Abc class pass to draw() a class full of properties. The properties in both cases would be the same, my question is what is preferred in this case. Maybe the second approach is more flexible? Maybe not? I don't see here a clear winner, but that sure has more to do with my inexperience than any other thing. If there are other good approaches, feel free to share them. Here are both cases: class Abc1 { public property a; public property b; public property c; ... public property z; public void method1(); ... public void methodn(); } and here is approach 2: class Abc2 { //here we make take down all properties public void method1(); ... public void methodn(); } class Abc2MethodArgs { //and we put them here. this class will be passed as argument to //Point's draw() method! public property a; public property b; public property c; ... public property z; } Also, if there are any "formal" names for these two approaches, I'd like to know them so I can better choose the tags/thread name, so it's more useful for searching purposes. That or feel free to edit them.

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• Connection between Properties of Entities in Data Oriented Design

  - by sharethis

  I want to start with an example illustrating my question. The following way it is done in the most games. class car { vec3 position; vec3 rotation; mesh model; imge texture; void move(); // modify position and rotation void draw(); // use model, texture, ... }; vector<car> cars; for(auto i = cars.begin(); i != cars.end(); ++i) { i->move(); i->draw(); } Data oriented design means to process the same calculation on the hole batch of data at once. This way it takes more advantage out of the processor cache. struct movedata { vec3 position; vec3 rotation; }; struct drawdata { mesh model; imge texture; }; vector<movedata> movedatas; vector<drawdata> drawdatas; for(auto i = movedatas.begin(); i != movedatas.end(); ++i) { // modify position and rotation } for(auto i = drawdatas.begin(); i != drawdatas.end(); ++i) { // use model, texture, ... } But there comes a point where you need to find other properties according to an entity. For example if the car crashes, I do not need the drawdata and the movedata any more. So I need to delete the entries of this entity in all vectors. The entries are not linked by code. So my question is the following. How are properties of the same entity conceptually linked in a data oriented design?

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• Visual Studio Design Time Property - Form List Drop Down

  - by Dustin Brooks

  I have a user control with a public property of the type Form. I want to be able to select a form at design time with a dropdown and populate it from a constant namespace: UI.Foo.Forms How do I go about doing this?

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• Persistance Queue Implementation

  - by Winter

  I was reading an article on Batch Processing in java over at JDJ http://java.sys-con.com/node/415321 . The article mentioned using a persistence queue as a Batch Updater instead of immediately sending an individual insert or update to the database. The author doesn't give a concrete example of this concept so I googled Persistence Queue but that didn't come up with much. Does anyone know of a good example of this?

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• Android::Creating a clickable collage?

  - by Legend

  I am trying to create something like a rectangular grid with pictures. When a picture is clicked, it should zoom in pushing the other ones out. I don't know what you name you call this particular model with but does anyone have suggestions on where I should start? Collage Example

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• What is the best way to restore(rollback) data in an application to a specified state(date) ?

  - by panzerschreck

  Hello, An example would set the context right, the example below captures the various states of the entity, which needs to be reverted(rolled back) . State 1 - Recorded on 01-Mar-2010 Column1 Column2 Data1 0.56 State 2 - Recorded on 02-Mar-2010 Column1 Column2 Data1 0.57 State 3 - Recorded on 03-Mar-2010 Column1 Column2 Data1 0.58 User notices that state3 is not what he intended to be in, decides to revert back to state2. One approach that I can think of, without modifying the entity is via "auditing" all the inserts/updates, as below, the rollback information captures the data just before the updates/modifications on the entity, so that it can be applied in an order when you need to revert.Please note that changing the entity's schema, is not an option. Rollback - R1 recorded on 01-Mar-2010 Column1 Column2 Data1 0.56 Rollback - R2 Recorded on 02-Mar-2010 Column1 Column2 Data1 0.56 Rollback - R3 Recorded on 03-Mar-2010 Column1 Column2 Data1 0.57 So, to get to state2 , we would start with rollback information R1,apply R2 onto it. Is there a better approach to achieve this ? Thanks for your time.

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• Creating design document from existing java code.

  - by BigBoss

  I have existing java code and need to create Design Document based on that. For starter even if I could get all functions with input / output parameters that will help in overall proces. Note: There is not commeted documentation on any procedures, function or classes. Last but not least. Let me know for any good tool which will reduce time required for this phase. As currently we write every flow and related stuffs.

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• set width height by a set a parameter in html

  - by Richa Media and services

  i need to set a image at 128*128px on a html page. i know the way width="128px" height="128px" but are i can do it by write a parameter on image like param="128px" then he set width and height 128px;

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• Design a mini script language

  - by radi

  hi , my project this year is to develop a text mining tool (with new features) so we need a mini script language in this tool to add annotation to texts this language should be simple and like lisp grammars (left and right side) . what i need is how to design this language ,i know how to constract the compiler , but how to write language grammars ? , and i want to use some mini open source language or any language bnf please advice me and if there is a language i can use and customize to meet my needs ? thanks

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• Trade Server Design

  - by Avinash

  Hi, Does anyone has Exchange Trader server design. I want to understand how does it work, does it required queues, to handle multiple trades how to add various observers to the each request .

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• Can you reccomend a podcast on OOP & Design?

  - by burak ozdogan

  Hi, Can you recommend me a web site providing pod-casts focused on OOP & Design? Thanks

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• Should the program logic reside inside the gui object class or be external to the class?

  - by hd112

  I have a question about how to structure code in relation to GUI objects. Suppose I have a dialog that has a list control that has a bunch of names obtained from a database. The user can edit the names. Does the logic reside inside that dialog class or should it be from the outside. To illustrate what I mean, here’s some pseudo code showing the structure of the code when the logic is handled outside the dialog class: NamesDialog : wxDialog { Private: ..stuff.. Public: ... SetNames(wxStringArray names); wxStringArray GetNames(); ..stuff.. } So the user of the class would do something like: wxStringArray names = DatabaseManager::Get()->GetNames(); names.Sort(); NamesDialogObject.SetNames(names); NamesDialogObject.ShowModal(); wxStringArray modified_names = NamesDialogObject.GetNames(); AddToDatabase(modified_names); //or something like this. On the other hand, the database logic can reside inside the NamesDialog class itself. In the show method I can query the database for the names and as the user interacts with the controls (list control in this case), the database can be updated from the event handlers. As a result the NamesDialog class only has the Show() method as there is no need to use SetNames or GetNames() etc. Which method is generally preferred? I don’t have much work experience so I’m not sure which is the proper way to handle it. Sometimes it's easier to handle everything in the class but getting access to objects it interacts with can be challenging. Generally can do it by having the relevant objects be singletons like the database manager in the above example.

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• Avoiding sub-type selection in view code

  - by John Donoghue

  Hi, I have some code where the model contains some classes like (vb.net pseudocode, but could be any OO language): Enum AttributeType Boolean Date String End Enum MustInherit Class Attibute Must Override Function Type As AttributeType End Class Class BooleanAttribute: Attribute Function Type As AttributeType Return AttributeType.Boolean End Function End Class And the view contains some code like: Select Case AttributeType Case Boolean //Display checkbox control Case Date //Display date picker control Case String //Display textbox control End Select I don't really like the code in the view, for the hopefully obvious reasons (what happens when I get a new attribute type etc). My question is, how should I replace it? I could easily add a method to the concrete classes, but that pollutes the model with UI stuff so that's a horrible idea. I could move the select into a factory, but that seems to be just hiding the problem. Can anybody advise a better approach?

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• Singleton Pattern Implementation Issues?

  - by locky28

  Hi I am revising for an exam and need to know some implementation issues with the singleton pattern. they do not need to be too complex just basic things that would affect a developers decision to include them, Thanks P.S. Could any code examples be given in Java thanks.

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• Enums and inheritance

  - by devoured elysium

  I will use (again) the following class hierarchy: Event and all the following classes inherit from Event: SportEventType1 SportEventType2 SportEventType3 SportEventType4 I have originally designed the Event class like this: public abstract class Event { public abstract EventType EventType { get; } public DateTime Time { get; protected set; } protected Event(DateTime time) { Time = time; } } with EventType being defined as: public enum EventType { Sport1, Sport2, Sport3, Sport4 } The original idea would be that each SportEventTypeX class would set its correct EventType. Now that I think of it, I think this approach is totally incorrect for two reasons: If I want to later add a new SportEventType class I will have to modify the enum If I later decide to remove one SportEventType that I feel I won't use I'm also in big trouble with the enum. I have a class variable in the Event class that makes, afterall, assumptions about the kind of classes that will inherit from it, which kinda defeats the purpose of inheritance. How would you solve this kind of situation? Define in the Event class an abstract "Description" property, having each child class implement it? Having an Attribute(Annotation in Java!) set its Description variable instead? What would be the pros/cons of having a class variable instead of attribute/annotation in this case? Is there any other more elegant solution out there? Thanks

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• HTML/CSS Design for Report

  - by Kevin Brown

  I'm looking for some resources that demonstrate good graphic design for generated (PHP/HTML/CSS) reports. The website I'm designing is essentially a long test. Everything is finished except the report generation, and this part needs to look good! I'd appreciate any advice/resources you can point me to! I know this isn't directly programming related, but my purposes do encompass coding and output.

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• How does Undo work?

  - by dontWatchMyProfile

  How does undo work? Does it copy all the managed objects every time any of the values change? Or does it only copy the actual changes together with an information which objects were affected? Is that heavy or lightweight?

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• Question About Classic MVC

  - by kernix

  Hello, In classic MVC the model notifies the view about changes made on it. In C# this means I have to subclass the View I'm interested in and in the subclassed class register to the model's event. For example, if I were to implement MVC using C# and Winforms, I had to subclass TextBox class and then register inside the MyTextBox's constructor for the model events. Am I correct? How was this issued in Smalltalk? Does one also need to subclass every View in order to register the model's events, or is there some way to dynamically add events to the views on the fly? Thanks

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