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  • String.IsNullOrWhiteSpace

    - by Scott Dorman
    An empty string is different than an unassigned string variable (which is null), and is a string containing no characters between the quotes (""). The .NET Framework provides String.Empty to represent an empty string, and there is no practical difference between ("") and String.Empty. One of the most common string comparisons to perform is to determine if a string variable is equal to an empty string. The fastest and simplest way to determine if a string is empty is to test if the Length property is equal to 0. However, since strings are reference types it is possible for a string variable to be null, which would result in a runtime error when you tried to access the Length property. Since testing to determine if a string is empty is such a common occurrence, the .NET Framework provides the static method String.IsNullOrEmpty method: public static bool IsNullOrEmpty(string value) { if (value != null) { return (value.Length == 0); }   return true; } It is also very common to determine if a string is empty and contains more than just whitespace characters. For example, String.IsNullOrEmpty("   ") would return false, since this string is actually made up of three whitespace characters. In some cases, this may be acceptable, but in many others it is not. TO help simplify testing this scenario, the .NET Framework 4 introduces the String.IsNullOrWhiteSpace method: public static bool IsNullOrWhiteSpace(string value) { if (value != null) { for (int i = 0; i < value.Length; i++) { if (!char.IsWhiteSpace(value[i])) { return false; } } } return true; }   Using either String.IsNullOrEmpty or String.IsNullOrWhiteSpace helps ensure correctness, readability, and consistency, so they should be used in all situations where you need to determine if a string is null, empty, or contains only whitespace characters. Technorati Tags: .NET,C# 4

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  • Visual Web Developer 2010 Express, automated testing, and SVN

    - by Mr. Jefferson
    We have an HTML designer who is not a developer but needs to modify .aspx files from our ASP.NET 2.0 projects from time to time in order to get CSS to work properly with them. Currently, this involves giving her the .aspx page by itself, which she opens and edits via Visual Studio 2008 (her computer used to be a developer's). I'm considering getting her set up with Visual Web Developer 2010 Express and Subversion access so she can be more independent, but I wanted to make sure VS Express will work properly with what we do. So: Does VWD 2010 Express support automated tests? If no to the above, what happens when it opens a solution file that includes a test project, modifies it, and saves it? Are there any potential snags with setting up AnkhSVN with VWD 2010 Express?

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  • How do you deal with translating theory into practice?

    - by Mr. Shickadance
    Hello all! Being a computer scientist in a research field I am often tasked with working alongside professionals outside of the software domain (think math people, electrical engineer etc), and then translating their theories and ideas into real-world implementations. I often find it difficult when they present a theoretical problem which appears to be somewhat disconnected from reality. I am not saying that the theory is bogus, only that it is difficult to translate into real-world situations. For example, recently I have been working with software defined radios. We are exploring many different areas, but often the math specialists in my group would present a problem which is heavily grounded in theory (signal processing, physics, whatever). I often struggle at times where it is hard to draw direct parallels between the theory and the real-world implementation that I need to develop. Say we are working on an energy detector, the theory person in my group would say "you need to measure the noise variance with no signal present." This leads me to think "how the hell do I isolate noise from a signal in reality?" There are many examples, but I hope you see where I am going. So, my question is how does one deal with implementation of theoretical concepts when the theory seems detached from reality? Or at least when the connections are not so clear. Or perhaps, the person with the 'theory' may be ignorant of real restrictions? Note: I found this to be a hard question to ask - hopefully you are following me. If you have suggestions on how I could improve it, by all means let me know! Thanks for looking! EDIT: To be a bit more clear, I understand in situations like this that I must learn that specific domain myself to an extent (i.e. signal processing), but I am more concerned with when those theoretical concepts do not appear to be as grounded in practice as one would like.

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  • Screen (command-line program) bug?

    - by VioletCrime
    fired up my Minecraft server again after about a year off. My server used to run 11.04, which has since been upgraded to 12.04; I lost my management scripts in the upgrade (thought I'd backed up the user's home directory), but whatever, I enjoy developing stuff like that anyways. However, this time around, I'm running into issues. I start the Minecraft server using a detached screen, however the script is unable to 'stuff' commands into the screen instance until I attach to the screen then detach again? Once I do that, I can stuff anything I want into the server's terminal using the -X option, until I stop/start the server again, then I have to reattach and detach in order to restore functionality? Here's the manager script: #!/bin/bash #Name of the screen housing the server (set with the -S flag at startup) SCREENNAME=minecraft1 #Name of the folder housing the Minecraft world FOLDERNAME=world1 startServer (){ if screen -list | grep "$SCREENNAME" > /dev/null then echo "Cannot start Minecraft server; it is already running!" else screen -dmS $SCREENNAME java -Xmx1024M -Xms1024M -jar minecraft_server.jar sleep 2 if screen -list | grep "$SCREENNAME" > /dev/null then echo "Minecraft server started; happy mining!" else echo "ERROR: Minecraft server failed to start!" fi fi; } stopServer (){ if screen -list | grep "$SCREENNAME" > /dev/null then echo "Server is running. Giving a 1-minute warning." screen -S $SCREENNAME -X stuff "/say Shutting down (halt) in one minute." screen -S $SCREENNAME -X stuff $'\015' sleep 45 screen -S $SCREENNAME -X stuff "/say Shutting down (halt) in 15 seconds." screen -S $SCREENNAME -X stuff $'\015' sleep 15 screen -S $SCREENNAME -X stuff "/stop" screen -S $SCREENNAME -X stuff $'\015' else echo "Server is not running; nothing to stop." fi; } stopServerNow (){ if screen -list | grep "$SCREENNAME" > /dev/null then echo "Server is running. Giving a 5-second warning." screen -S $SCREENNAME -X stuff "/say EMERGENCY SHUTDOWN! 5 seconds to halt." screen -S $SCREENNAME -X stuff $'\015' sleep 5 screen -S $SCREENNAME -X stuff "/stop" screen -S $SCREENNAME -X stuff $'\015' else echo "Server is not running; nothing to stop." fi; } restartServer (){ if screen -list | grep "$SCREENNAME" > /dev/null then echo "Server is running. Giving a 1-minute warning." screen -S $SCREENNAME -X stuff "/say Shutting down (restart) in one minute." screen -S $SCREENNAME -X stuff $'\015' sleep 45 screen -S $SCREENNAME -X stuff "/say Shutting down (restart) in 15 seconds." screen -S $SCREENNAME -X stuff $'\015' sleep 15 screen -S $SCREENNAME -X stuff "/stop" screen -S $SCREENNAME -X stuff $'\015' sleep 2 startServer else echo "Cannot restart server: it isn't running." fi; } #In order for this function to work, a directory 'backup/$FOLDERNAME' must exist in the same #directory that '$FOLDERNAME' resides backupWorld (){ if screen -list | grep "$SCREENNAME" > /dev/null then echo "Server is running. Giving a 1-minute warning." screen -S $SCREENNAME -X stuff "/say Shutting down (backup) in one minute." screen -S $SCREENNAME -X stuff $'\015' screen -S $SCREENNAME -X stuff "/say Server should be down for no more than a few seconds." screen -S $SCREENNAME -X stuff $'\015' sleep 45 screen -S $SCREENNAME -X stuff "/say Shutting down for backup in 15 seconds." screen -S $SCREENNAME -X stuff $'\015' sleep 15 screen -S $SCREENNAME -X stuff "/stop" screen -S $SCREENNAME -X stuff $'\015' fi sleep 2 if screen -list | grep $SCREENNAME > /dev/null then echo "Server is still running? Error." else cd .. tar -czvf backup0.tar.gz $FOLDERNAME mv backup0.tar.gz backup/$FOLDERNAME cd backup/$FOLDERNAME rm backup10.tar.gz mv backup9.tar.gz backup10.tar.gz mv backup8.tar.gz backup9.tar.gz mv backup7.tar.gz backup8.tar.gz mv backup6.tar.gz backup7.tar.gz mv backup5.tar.gz backup6.tar.gz mv backup4.tar.gz backup5.tar.gz mv backup3.tar.gz backup4.tar.gz mv backup2.tar.gz backup3.tar.gz mv backup1.tar.gz backup2.tar.gz mv backup0.tar.gz backup1.tar.gz cd ../../$FOLDERNAME screen -dmS $SCREENNAME java -Xmx1024M -Xms1024M -jar minecraft_server.jar; sleep 2 if screen -list | grep "$SCREENNAME" > /dev/null then echo "Minecraft server restarted; happy mining!" else echo "ERROR: Minecraft server failed to start!" fi fi; } printCommands (){ echo echo "$0 usage:" echo echo "Start : Starts the server on a detached screen." echo "Stop : Stop the server; includes a 1-minute warning." echo "StopNOW : Stops the server with only a 5-second warning." echo "Restart : Stops the server and starts the server again." echo "Backup : Stops the server (1 min), backs up the world, and restarts." echo "Help : Display this message." } #Forces case-insensitive string comparisons shopt -s nocasematch #Primary 'Switch' if [[ $1 = "start" ]] then startServer elif [[ $1 = "stop" ]] then stopServer elif [[ $1 = "stopnow" ]] then stopServerNow elif [[ $1 = "backup" ]] then backupWorld elif [[ $1 = "restart" ]] then restartServer else printCommands fi

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  • Change Data Capture

    - by Ricardo Peres
    There's an hidden gem in SQL Server 2008: Change Data Capture (CDC). Using CDC we get full audit capabilities with absolutely no implementation code: we can see all changes made to a specific table, including the old and new values! You can only use CDC in SQL Server 2008 Standard or Enterprise, Express edition is not supported. Here are the steps you need to take, just remember SQL Agent must be running: use SomeDatabase; -- first create a table CREATE TABLE Author ( ID INT NOT NULL PRIMARY KEY IDENTITY(1, 1), Name NVARCHAR(20) NOT NULL, EMail NVARCHAR(50) NOT NULL, Birthday DATE NOT NULL ) -- enable CDC at the DB level EXEC sys.sp_cdc_enable_db -- check CDC is enabled for the current DB SELECT name, is_cdc_enabled FROM sys.databases WHERE name = 'SomeDatabase' -- enable CDC for table Author, all columns exec sys.sp_cdc_enable_table @source_schema = 'dbo', @source_name = 'Author', @role_name = null -- insert values into table Author insert into Author (Name, EMail, Birthday, Username) values ('Bla', 'bla@bla', 1990-10-10, 'bla') -- check CDC data for table Author -- __$operation: 1 = DELETE, 2 = INSERT, 3 = BEFORE UPDATE 4 = AFTER UPDATE -- __$start_lsn: operation timestamp select * from cdc.dbo_author_CT -- update table Author update Author set EMail = '[email protected]' where Name = 'Bla' -- check CDC data for table Author select * from cdc.dbo_author_CT -- delete from table Author delete from Author -- check CDC data for table Author select * from cdc.dbo_author_CT -- disable CDC for table Author -- this removes all CDC data, so be carefull exec sys.sp_cdc_disable_table @source_schema = 'dbo', @source_name = 'Author', @capture_instance = 'dbo_Author' -- disable CDC for the entire DB -- this removes all CDC data, so be carefull exec sys.sp_cdc_disable_db SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.all();

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  • texture mapping with lib3ds and SOIL help

    - by Adam West
    I'm having trouble with my project for loading a texture map onto a model. Any insight into what is going wrong with my code is fantastic. Right now the code only renders a teapot which I have assinged after creating it in 3DS Max. 3dsloader.cpp #include "3dsloader.h" Object::Object(std:: string filename) { m_TotalFaces = 0; m_model = lib3ds_file_load(filename.c_str()); // If loading the model failed, we throw an exception if(!m_model) { throw strcat("Unable to load ", filename.c_str()); } // set properties of texture coordinate generation for both x and y coordinates glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); // if not already enabled, enable texture generation if(! glIsEnabled(GL_TEXTURE_GEN_S)) glEnable(GL_TEXTURE_GEN_S); if(! glIsEnabled(GL_TEXTURE_GEN_T)) glEnable(GL_TEXTURE_GEN_T); } Object::~Object() { if(m_model) // if the file isn't freed yet lib3ds_file_free(m_model); //free up memory glDisable(GL_TEXTURE_GEN_S); glDisable(GL_TEXTURE_GEN_T); } void Object::GetFaces() { m_TotalFaces = 0; Lib3dsMesh * mesh; // Loop through every mesh. for(mesh = m_model->meshes;mesh != NULL;mesh = mesh->next) { // Add the number of faces this mesh has to the total number of faces. m_TotalFaces += mesh->faces; } } void Object::CreateVBO() { assert(m_model != NULL); // Calculate the number of faces we have in total GetFaces(); // Allocate memory for our vertices and normals Lib3dsVector * vertices = new Lib3dsVector[m_TotalFaces * 3]; Lib3dsVector * normals = new Lib3dsVector[m_TotalFaces * 3]; Lib3dsTexel* texCoords = new Lib3dsTexel[m_TotalFaces * 3]; Lib3dsMesh * mesh; unsigned int FinishedFaces = 0; // Loop through all the meshes for(mesh = m_model->meshes;mesh != NULL;mesh = mesh->next) { lib3ds_mesh_calculate_normals(mesh, &normals[FinishedFaces*3]); // Loop through every face for(unsigned int cur_face = 0; cur_face < mesh->faces;cur_face++) { Lib3dsFace * face = &mesh->faceL[cur_face]; for(unsigned int i = 0;i < 3;i++) { memcpy(&texCoords[FinishedFaces*3 + i], mesh->texelL[face->points[ i ]], sizeof(Lib3dsTexel)); memcpy(&vertices[FinishedFaces*3 + i], mesh->pointL[face->points[ i ]].pos, sizeof(Lib3dsVector)); } FinishedFaces++; } } // Generate a Vertex Buffer Object and store it with our vertices glGenBuffers(1, &m_VertexVBO); glBindBuffer(GL_ARRAY_BUFFER, m_VertexVBO); glBufferData(GL_ARRAY_BUFFER, sizeof(Lib3dsVector) * 3 * m_TotalFaces, vertices, GL_STATIC_DRAW); // Generate another Vertex Buffer Object and store the normals in it glGenBuffers(1, &m_NormalVBO); glBindBuffer(GL_ARRAY_BUFFER, m_NormalVBO); glBufferData(GL_ARRAY_BUFFER, sizeof(Lib3dsVector) * 3 * m_TotalFaces, normals, GL_STATIC_DRAW); // Generate a third VBO and store the texture coordinates in it. glGenBuffers(1, &m_TexCoordVBO); glBindBuffer(GL_ARRAY_BUFFER, m_TexCoordVBO); glBufferData(GL_ARRAY_BUFFER, sizeof(Lib3dsTexel) * 3 * m_TotalFaces, texCoords, GL_STATIC_DRAW); // Clean up our allocated memory delete vertices; delete normals; delete texCoords; // We no longer need lib3ds lib3ds_file_free(m_model); m_model = NULL; } void Object::applyTexture(const char*texfilename) { float imageWidth; float imageHeight; glGenTextures(1, & textureObject); // allocate memory for one texture textureObject = SOIL_load_OGL_texture(texfilename,SOIL_LOAD_AUTO,SOIL_CREATE_NEW_ID,SOIL_FLAG_MIPMAPS); glPixelStorei(GL_UNPACK_ALIGNMENT,1); glBindTexture(GL_TEXTURE_2D, textureObject); // use our newest texture glGetTexLevelParameterfv(GL_TEXTURE_2D,0,GL_TEXTURE_WIDTH,&imageWidth); glGetTexLevelParameterfv(GL_TEXTURE_2D,0,GL_TEXTURE_HEIGHT,&imageHeight); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // give the best result for texture magnification glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); //give the best result for texture minification glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); // don't repeat texture glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); // don't repeat textureglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); // don't repeat texture glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,GL_MODULATE); glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,imageWidth,imageHeight,0,GL_RGB,GL_UNSIGNED_BYTE,& textureObject); } void Object::Draw() const { // Enable vertex, normal and texture-coordinate arrays. glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_NORMAL_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); // Bind the VBO with the normals. glBindBuffer(GL_ARRAY_BUFFER, m_NormalVBO); // The pointer for the normals is NULL which means that OpenGL will use the currently bound VBO. glNormalPointer(GL_FLOAT, 0, NULL); glBindBuffer(GL_ARRAY_BUFFER, m_TexCoordVBO); glTexCoordPointer(2, GL_FLOAT, 0, NULL); glBindBuffer(GL_ARRAY_BUFFER, m_VertexVBO); glVertexPointer(3, GL_FLOAT, 0, NULL); // Render the triangles. glDrawArrays(GL_TRIANGLES, 0, m_TotalFaces * 3); glDisableClientState(GL_VERTEX_ARRAY); glDisableClientState(GL_NORMAL_ARRAY); glDisableClientState(GL_TEXTURE_COORD_ARRAY); } 3dsloader.h #include "main.h" #include "lib3ds/file.h" #include "lib3ds/mesh.h" #include "lib3ds/material.h" class Object { public: Object(std:: string filename); virtual ~Object(); virtual void Draw() const; virtual void CreateVBO(); void applyTexture(const char*texfilename); protected: void GetFaces(); unsigned int m_TotalFaces; Lib3dsFile * m_model; Lib3dsMesh* Mesh; GLuint textureObject; GLuint m_VertexVBO, m_NormalVBO, m_TexCoordVBO; }; Called in the main cpp file with: VBO,apply texture and draw (pretty simple, how ironic) and thats it, please help me forum :)

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  • How to change metamode in xorg.conf so that my game in FHD will be displayed only in the external monitor?

    - by Patryk
    I would like to launch my game only in the external monitor which I have attached to my laptop with hdmi cable. This is my current xorg.conf # nvidia-xconfig: X configuration file generated by nvidia-xconfig # nvidia-xconfig: version 319.60 (buildmeister@swio-display-x64-rhel04-15) Wed Sep 25 15:17:31 PDT 2013 Section "ServerLayout" Identifier "Layout0" Screen 0 "Screen0" InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" EndSection Section "Files" EndSection Section "InputDevice" # generated from default Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/psaux" Option "Emulate3Buttons" "no" Option "ZAxisMapping" "4 5" EndSection Section "InputDevice" # generated from default Identifier "Keyboard0" Driver "kbd" EndSection Section "Monitor" Identifier "Monitor0" VendorName "Unknown" ModelName "Unknown" HorizSync 28.0 - 33.0 VertRefresh 43.0 - 72.0 Option "DPMS" EndSection Section "Device" Identifier "Device0" Driver "nvidia" VendorName "NVIDIA Corporation" EndSection Section "Screen" Identifier "Screen0" Device "Device0" Monitor "Monitor0" DefaultDepth 24 Option "metamodes" "1024x786,NULL;1280x720,NULL;NULL,1680x1050;NULL,1920x1080" SubSection "Display" Depth 24 EndSubSection EndSection Although with this config nothing changes (I have my game displayed in the laptop screen and exceeding a little bit onto the external monitor since I set it to be in 1920x1080) I have read this https://help.ubuntu.com/community/XineramaHowTo but with no luck of solving this issue. The only temporary solution for this problem now is to manually switch of the laptop display and then launch the game.

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  • Software Development Realated Magazines? [closed]

    - by Mr Programmer
    Possible Duplicate: What are some well-respected programmers magazines? Both online and print I would like to know some good software development related magazines which introduce us to the new technologies as earlier as possible. Please tell me some top software development related magazines. There's no software development related magazine in my college library. So I've spoken to a library committee member and he told me to get the complete details of a magazine and set a price frame - about 3000 Indian Rupees. So please make sure the annual subscription price is Less than $70. Thank you.

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  • How to create projection/view matrix for hole in the monitor effect

    - by Mr Bell
    Lets say I have my XNA app window that is sized at 640 x 480 pixels. Now lets say I have a cube model with its poly's facing in to make a room. This cube is sized 640 units wide by 480 units high by 480 units deep. Lets say the camera is somewhere in front of the box looking at it. How can I set up the view and projection matrices such that the front edge of the box lines up exactly with the edges of the application window? It seems like this should probably involve the Matrix.CreatePerspectiveOffCenter method, but I don't fully understand how the parameters translate on to the screen. For reference, the end result will be something like Johhny Lee's wii head tracking demo: http://www.youtube.com/watch?v=Jd3-eiid-Uw&feature=player_embedded P.S. I realize that his source code is available, but I am afraid I haven't been able to make heads or tails out of it.

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  • Confused about ASP.NET Ajax, jQuery and JavaScript

    - by Mr.Y
    Yesterday, I read couple of chapters on ASP.NET Ajax and jQuery from my ASP.NET 4 book and I found those frameworks pretty interesting and decide to learn more about them. Today, I borrowed some books from library on Ajax and JavaScript. It seems ASP.NET Ajax is different from Ajax and jQuery seems like the "new" JavaScript. Does it mean that I can skip JavaScript and learn jQuery directly? On the other hand, the non-ASP.NET Ajax book I borrowed seems to apply to the client side web programming only and looks quite different from what I learned from ASP.NET Ajax. If I'm an ASP.NET developer, I guess I should stick with ASP.NET Ajax instead of client side Ajax right? What about PHP? Is there a "PHP Ajax" similar to ASP.NET Ajax? It's not that I'm lazy to learn other tools, but I just want to focus on the right ones.

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  • Implementing camera for 2d side scroller game ?

    - by Mr.Gando
    Hello, I'm implementing a 2D side scroller for iOS (using C/C++ with OpenGL) (beat'em up style like double dragon/final fight ). My scenes are composed of one cyclical background image ( the end of the image connects perfectly with the beginning ). This is to produce a cyclical scroll effect. I was wondering how could I implement a camera that follows my player movement ? ( Resources / Links are greatly appreciated with explanations :) )

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  • Linux for web Development [closed]

    - by Mr.TAMER
    I usually used windows for developing desktop applications, but recently I've almost abandoned desktop apps and have been doing web development so much. I'm using many web technologies and languages, especially Ruby on Rails, and I'm facing too many problems using windows. Besides, I personally want to move to Linux. So, what's the most helpful and comfortable Linux distribution for web development? I have a short but handy experience using Ubuntu desktop, so I'm familiar with the generics of Linux (like -as a simple example- using the command line), and I don't have any problem in getting used to any distribution (I know I may face some difficulties, but again I have no problem), I only want the best one for web development (especially rails!!). If the question doesn't belong to this site, I'll be glad to migrate it to the appropriate one.

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  • Best memory allocation strategy for iOS ?

    - by Mr.Gando
    Hey guys, I'm debating myself about memory allocation on iOS. I write most of my code in C++ and I really like using ObjectPools, FreeLists, etc. In order to pre-allocate a lot of the stuff that I'll be constantly "alloc/dealloc" during the course of my game, ( like particles, game entities, etc ). Still on iOS, it's not like we are developing for a console like PSP, where I can know for fact that I'll get a fixed amount of memory. iOS , will issue "memory warnings" when the system needs memory. Does anyone have some suggestions about this ? Is it too serious since the new iPod touch/iPhone 4 are carrying more RAM ? or it's still a big concern ? Thanks!

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  • Design review for application facing memory issues

    - by Mr Moose
    I apologise in advance for the length of this post, but I want to paint an accurate picture of the problems my app is facing and then pose some questions below; I am trying to address some self inflicted design pain that is now leading to my application crashing due to out of memory errors. An abridged description of the problem domain is as follows; The application takes in a “dataset” that consists of numerous text files containing related data An individual text file within the dataset usually contains approx 20 “headers” that contain metadata about the data it contains. It also contains a large tab delimited section containing data that is related to data in one of the other text files contained within the dataset. The number of columns per file is very variable from 2 to 256+ columns. The original application was written to allow users to load a dataset, map certain columns of each of the files which basically indicating key information on the files to show how they are related as well as identify a few expected column names. Once this is done, a validation process takes place to enforce various rules and ensure that all the relationships between the files are valid. Once that is done, the data is imported into a SQL Server database. The database design is an EAV (Entity-Attribute-Value) model used to cater for the variable columns per file. I know EAV has its detractors, but in this case, I feel it was a reasonable choice given the disparate data and variable number of columns submitted in each dataset. The memory problem Given the fact the combined size of all text files was at most about 5 megs, and in an effort to reduce the database transaction time, it was decided to read ALL the data from files into memory and then perform the following; perform all the validation whilst the data was in memory relate it using an object model Start DB transaction and write the key columns row by row, noting the Id of the written row (all tables in the database utilise identity columns), then the Id of the newly written row is applied to all related data Once all related data had been updated with the key information to which it relates, these records are written using SqlBulkCopy. Due to our EAV model, we essentially have; x columns by y rows to write, where x can by 256+ and rows are often into the tens of thousands. Once all the data is written without error (can take several minutes for large datasets), Commit the transaction. The problem now comes from the fact we are now receiving individual files containing over 30 megs of data. In a dataset, we can receive any number of files. We’ve started seen datasets of around 100 megs coming in and I expect it is only going to get bigger from here on in. With files of this size, data can’t even be read into memory without the app falling over, let alone be validated and imported. I anticipate having to modify large chunks of the code to allow validation to occur by parsing files line by line and am not exactly decided on how to handle the import and transactions. Potential improvements I’ve wondered about using GUIDs to relate the data rather than relying on identity fields. This would allow data to be related prior to writing to the database. This would certainly increase the storage required though. Especially in an EAV design. Would you think this is a reasonable thing to try, or do I simply persist with identity fields (natural keys can’t be trusted to be unique across all submitters). Use of staging tables to get data into the database and only performing the transaction to copy data from staging area to actual destination tables. Questions For systems like this that import large quantities of data, how to you go about keeping transactions small. I’ve kept them as small as possible in the current design, but they are still active for several minutes and write hundreds of thousands of records in one transaction. Is there a better solution? The tab delimited data section is read into a DataTable to be viewed in a grid. I don’t need the full functionality of a DataTable, so I suspect it is overkill. Is there anyway to turn off various features of DataTables to make them more lightweight? Are there any other obvious things you would do in this situation to minimise the memory footprint of the application described above? Thanks for your kind attention.

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  • The value of an updated specification

    - by Mr. Jefferson
    I'm at the tail end of a large project (around 5 months of my time, 60,000 lines of code) on which I was the only developer. The specification documents for the project were designed well early on, but as always happens during development, some things have changed. For example: Bugs were discovered and fixed in ways that don't correspond well with the spec Additional needs were discovered and dealt with We found areas where the spec hadn't thought far enough ahead and had to change some implementation Etc. Through all this, the spec was not kept updated, because we were lean on resources (I know that's a questionable excuse). I'm hoping to get the spec updated soon when we have time, but it's a matter of convincing management to spend the effort. I believe it's a good idea, but I need some good reasoning; I can't speak from very much experience because I'm only a year and a half out of school. So here are my questions: What value is there in keeping an updated spec? How often should the spec be updated? With every change made that might affect it, just at the end of development, or something in between? EDIT to clarify: this project was internal, so no external client was involved. It's our product.

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  • Creating a GTK theme, but Qt and Java apps are not affected, and title bar button layout is ugly

    - by Mr. Pixel
    I'm playing with a gtk2 / gtk3 theme which I use in the Mate desktop. Everything is looking well, even gtk3 apps, but I still have 3 important issues: Java apps ignore the theme QT apps ignore the theme I'm using those nice ubuntu 10 title bar buttons, but the problem is, when only the close button appears, the title bar looks ugly. Can I make it so that it shows the two other buttons, but disabled? I don't know how Ubuntu 10 handled this. Here's a screenshot showing the 3 problems (above is a small java app, below is a Qt app): Under my previous desktop environments, Unity and Cinnamon, both apps seemed to be taking the right theme correctly, but I did not use my custom theme yet. Cinnamon is based on gnome-shell by the way, and mate is a gnome2-fork. Please note that the shown java app explicitely tries to load the gtk theme at runtime. By default, java apps don't, but this one has the necessary code, which worked in unity and cinnamon. Any suggestions how I could make my theme better so these problems disappear? Thank you very much!

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  • Wisdom of using open source code in a commercial software product

    - by Mr. Jefferson
    I'm looking at using some open source code in my ASP.NET web app (specifically dapper). Management is not a fan, because open source is seen as a risk that has bitten us before. Apparently previous developers have had to rewrite things after having open-source components fail. The pros seem to be: It does a lot of stuff for me that would otherwise involve either lots of boilerplate code or Microsoft's recommended but slower solution (Entity Framework). Cons: It's complex enough that if it were to fail suddenly in production, I would be hard pressed to fix it. However, it's in use on a much higher-traffic site than mine, so I don't think it'll end up being a high risk portion of the project. What is the consensus here? Is it unwise to use open source code in my project that I don't know/understand as well as I do my own code?

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  • Is it possible to have multiple sets of key columns in a table?

    - by Peter Larsson
    Filtered indexes is one of my new favorite things with SQL Server 2008. I am currently working on designing a new datawarehouse. There are two restrictions doing this It has to be fed from the old legacy system with both historical data and new data It has to be fed from the new business system with new data When we incorporate the new business system, we are going to do that for one market only. It means the old legacy business system still will produce new data for other markets (together with historical data for all markets) and the new business system produce new data to that one market only. Sounds interesting this far? To accomplish this I did a thorough research about the business requirements about the business intelligence needs. Then I went on to design the sucker. How does this relate to filtered indexes you ask? I'll give one example, the Stock transaction table. Well, the key columns for the old legacy system are different from the key columns from the new business system. The old legacy system has a key of 5 columns Movement date Movement time Product code Order number Sequence number within shipment And to all thing, I found out that the Movement Time column is not really a time. It starts out like a time HH:MM:SS but seconds are added for each delivery within the shipment, so a Movement Time can look like "12:11:68". The sequence number is ordered over the distributors for shipment. As I said, it is a legacy system. The new business system has one key column, the Movement DateTime (accuracy down to 100th of nanosecond). So how to deal with this? On thing would be to have two stock transaction tables, one for legacy system and one for the new business system. But that would lead to a maintenance overhead and using partitioned views for getting data out of the warehouse. Filtered index will be of a great use here. MovementDate DATETIME2(7) MovementTime CHAR(8) NULL ProductCode VARCHAR(15) NOT NULL OrderNumber VARCHAR(30) NULL SequenceNumber INT NULL The sequence number is not even used in the new system, so I created a clustered index for a new IDENTITY column to make a new identity column which can be shared by both systems. Then I created one unique filtered index for old system like this CREATE UNIQUE NONCLUSTERED INDEX IX_Legacy (MovementDate, MovementTime, ProductCode, SequenceNumber) INCLUDE (OrderNumber, Col5, Col6, ... ) WHERE SequenceNumber IS NOT NULL And then I created a new unique filtered index for the new business system like this CREATE UNIQUE NONCLUSTERED INDEX IX_Business (MovementDate) INCLUDE (ProductCode, OrderNumber, Col12, ... ) WHERE SequenceNumber IS NULL This way I can have multiple sets of key columns on same base table which is shared by both systems.

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  • C#: Handling Notifications: inheritance, events, or delegates?

    - by James Michael Hare
    Often times as developers we have to design a class where we get notification when certain things happen. In older object-oriented code this would often be implemented by overriding methods -- with events, delegates, and interfaces, however, we have far more elegant options. So, when should you use each of these methods and what are their strengths and weaknesses? Now, for the purposes of this article when I say notification, I'm just talking about ways for a class to let a user know that something has occurred. This can be through any programmatic means such as inheritance, events, delegates, etc. So let's build some context. I'm sitting here thinking about a provider neutral messaging layer for the place I work, and I got to the point where I needed to design the message subscriber which will receive messages from the message bus. Basically, what we want is to be able to create a message listener and have it be called whenever a new message arrives. Now, back before the flood we would have done this via inheritance and an abstract class: 1:  2: // using inheritance - omitting argument null checks and halt logic 3: public abstract class MessageListener 4: { 5: private ISubscriber _subscriber; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber) 11: { 12: _subscriber = subscriber; 13: _messageThread = new Thread(MessageLoop); 14: _messageThread.Start(); 15: } 16:  17: // user will override this to process their messages 18: protected abstract void OnMessageReceived(Message msg); 19:  20: // handle the looping in the thread 21: private void MessageLoop() 22: { 23: while(!_isHalted) 24: { 25: // as long as processing, wait 1 second for message 26: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 27: if(msg != null) 28: { 29: OnMessageReceived(msg); 30: } 31: } 32: } 33: ... 34: } It seems so odd to write this kind of code now. Does it feel odd to you? Maybe it's just because I've gotten so used to delegation that I really don't like the feel of this. To me it is akin to saying that if I want to drive my car I need to derive a new instance of it just to put myself in the driver's seat. And yet, unquestionably, five years ago I would have probably written the code as you see above. To me, inheritance is a flawed approach for notifications due to several reasons: Inheritance is one of the HIGHEST forms of coupling. You can't seal the listener class because it depends on sub-classing to work. Because C# does not allow multiple-inheritance, I've spent my one inheritance implementing this class. Every time you need to listen to a bus, you have to derive a class which leads to lots of trivial sub-classes. The act of consuming a message should be a separate responsibility than the act of listening for a message (SRP). Inheritance is such a strong statement (this IS-A that) that it should only be used in building type hierarchies and not for overriding use-specific behaviors and notifications. Chances are, if a class needs to be inherited to be used, it most likely is not designed as well as it could be in today's modern programming languages. So lets look at the other tools available to us for getting notified instead. Here's a few other choices to consider. Have the listener expose a MessageReceived event. Have the listener accept a new IMessageHandler interface instance. Have the listener accept an Action<Message> delegate. Really, all of these are different forms of delegation. Now, .NET events are a bit heavier than the other types of delegates in terms of run-time execution, but they are a great way to allow others using your class to subscribe to your events: 1: // using event - ommiting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private bool _isHalted = false; 6: private Thread _messageThread; 7:  8: // assign the subscriber and start the messaging loop 9: public MessageListener(ISubscriber subscriber) 10: { 11: _subscriber = subscriber; 12: _messageThread = new Thread(MessageLoop); 13: _messageThread.Start(); 14: } 15:  16: // user will override this to process their messages 17: public event Action<Message> MessageReceived; 18:  19: // handle the looping in the thread 20: private void MessageLoop() 21: { 22: while(!_isHalted) 23: { 24: // as long as processing, wait 1 second for message 25: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 26: if(msg != null && MessageReceived != null) 27: { 28: MessageReceived(msg); 29: } 30: } 31: } 32: } Note, now we can seal the class to avoid changes and the user just needs to provide a message handling method: 1: theListener.MessageReceived += CustomReceiveMethod; However, personally I don't think events hold up as well in this case because events are largely optional. To me, what is the point of a listener if you create one with no event listeners? So in my mind, use events when handling the notification is optional. So how about the delegation via interface? I personally like this method quite a bit. Basically what it does is similar to inheritance method mentioned first, but better because it makes it easy to split the part of the class that doesn't change (the base listener behavior) from the part that does change (the user-specified action after receiving a message). So assuming we had an interface like: 1: public interface IMessageHandler 2: { 3: void OnMessageReceived(Message receivedMessage); 4: } Our listener would look like this: 1: // using delegation via interface - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private IMessageHandler _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler.OnMessageReceived(msg); 28: } 29: } 30: } 31: } And they would call it by creating a class that implements IMessageHandler and pass that instance into the constructor of the listener. I like that this alleviates the issues of inheritance and essentially forces you to provide a handler (as opposed to events) on construction. Well, this is good, but personally I think we could go one step further. While I like this better than events or inheritance, it still forces you to implement a specific method name. What if that name collides? Furthermore if you have lots of these you end up either with large classes inheriting multiple interfaces to implement one method, or lots of small classes. Also, if you had one class that wanted to manage messages from two different subscribers differently, it wouldn't be able to because the interface can't be overloaded. This brings me to using delegates directly. In general, every time I think about creating an interface for something, and if that interface contains only one method, I start thinking a delegate is a better approach. Now, that said delegates don't accomplish everything an interface can. Obviously having the interface allows you to refer to the classes that implement the interface which can be very handy. In this case, though, really all you want is a method to handle the messages. So let's look at a method delegate: 1: // using delegation via delegate - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler(msg); 28: } 29: } 30: } 31: } Here the MessageListener now takes an Action<Message>.  For those of you unfamiliar with the pre-defined delegate types in .NET, that is a method with the signature: void SomeMethodName(Message). The great thing about delegates is it gives you a lot of power. You could create an anonymous delegate, a lambda, or specify any other method as long as it satisfies the Action<Message> signature. This way, you don't need to define an arbitrary helper class or name the method a specific thing. Incidentally, we could combine both the interface and delegate approach to allow maximum flexibility. Doing this, the user could either pass in a delegate, or specify a delegate interface: 1: // using delegation - give users choice of interface or delegate 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // passes the interface method as a delegate using method group 19: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 20: : this(subscriber, handler.OnMessageReceived) 21: { 22: } 23:  24: // handle the looping in the thread 25: private void MessageLoop() 26: { 27: while(!_isHalted) 28: { 29: // as long as processing, wait 1 second for message 30: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 31: if(msg != null) 32: { 33: _handler(msg); 34: } 35: } 36: } 37: } } This is the method I tend to prefer because it allows the user of the class to choose which method works best for them. You may be curious about the actual performance of these different methods. 1: Enter iterations: 2: 1000000 3:  4: Inheritance took 4 ms. 5: Events took 7 ms. 6: Interface delegation took 4 ms. 7: Lambda delegate took 5 ms. Before you get too caught up in the numbers, however, keep in mind that this is performance over over 1,000,000 iterations. Since they are all < 10 ms which boils down to fractions of a micro-second per iteration so really any of them are a fine choice performance wise. As such, I think the choice of what to do really boils down to what you're trying to do. Here's my guidelines: Inheritance should be used only when defining a collection of related types with implementation specific behaviors, it should not be used as a hook for users to add their own functionality. Events should be used when subscription is optional or multi-cast is desired. Interface delegation should be used when you wish to refer to implementing classes by the interface type or if the type requires several methods to be implemented. Delegate method delegation should be used when you only need to provide one method and do not need to refer to implementers by the interface name.

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  • PLINQ Adventure Land - WaitForAll

    - by adweigert
    PLINQ is awesome for getting a lot of work done fast, but one thing I haven't figured out yet is how to start work with PLINQ but only let it execute for a maximum amount of time and react if it is taking too long. So, as I must admit I am still learning PLINQ, I created this extension in that ignorance. It behaves similar to ForAll<> but takes a timeout and returns false if the threads don't complete in the specified amount of time. Hope this helps someone else take PLINQ further, it definitely has helped for me ...  public static bool WaitForAll<T>(this ParallelQuery<T> query, TimeSpan timeout, Action<T> action) { Contract.Requires(query != null); Contract.Requires(action != null); var exception = (Exception)null; var cts = new CancellationTokenSource(); var forAllWithCancellation = new Action(delegate { try { query.WithCancellation(cts.Token).ForAll(action); } catch (OperationCanceledException) { // NOOP } catch (AggregateException ex) { exception = ex; } }); var mrs = new ManualResetEvent(false); var callback = new AsyncCallback(delegate { mrs.Set(); }); var result = forAllWithCancellation.BeginInvoke(callback, null); if (mrs.WaitOne(timeout)) { forAllWithCancellation.EndInvoke(result); if (exception != null) { throw exception; } return true; } else { cts.Cancel(); return false; } }

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  • Firefox on wine crashes on startup on Ubuntu

    - by Iam Zesh
    First, let's explain why I want Firefox under wine, and not the Firefox that is shipped out of the box with Ubuntu. I want to use Firefox under wine because I want to use the Widevine addon, which is "at this time not available for linux". Here is what I did so far to install and use Firefox on wine. On Ubuntu 12.04 LTS, I just installed wine like that: sudo apt-get update; sudo apt-get install wine Then I downloaded the windows installer for Firefox from the mozilla website. I ran the Firefox Setup 25.0.exe file with wine but at the end of the install process when launching Firefox, I got a window notifying me that the program at crashed. I ran Firefox from the command line with wine, to get an idea of what could have went wrong: wine /home/myUser/.wine/drive_c/Program\ Files/Mozilla\ Firefox/firefox.exe fixme:heap:HeapSetInformation (nil) 1 (nil) 0 fixme:process:SetProcessDEPPolicy (1): stub fixme:iphlpapi:NotifyAddrChange (Handle 0x368e8fc, overlapped 0x368e8e0): stub fixme:winsock:WSCGetProviderPath ({e70f1aa0-ab8b-11cf-8ca3-00805f48a192} 0x44fe6f8 0x44fe6b8 0x44fe6e4) Stub! fixme:advapi:RegisterTraceGuidsW (0x1b0e290, 0x39ead80, {509962e0-406b-46f4-99ba-5a009f8d2225}, 3, 0x3974d00, (null), (null), 0x39eadb0,): stub fixme:winsock:WSCGetProviderPath ({e70f1aa0-ab8b-11cf-8ca3-00805f48a192} 0x44fe6f8 0x44fe6b8 0x44fe6e4) Stub! fixme:winsock:WSCGetProviderPath ({11058240-be47-11cf-95c8-00805f48a192} 0x44fe6f8 0x44fe6b8 0x44fe6e4) Stub! fixme:winsock:WSCGetProviderPath ({11058241-be47-11cf-95c8-00805f48a192} 0x44fe6f8 0x44fe6b8 0x44fe6e4) Stub! fixme:winsock:WSCGetProviderPath ({11058241-be47-11cf-95c8-00805f48a192} 0x44fe6f8 0x44fe6b8 0x44fe6e4) Stub! fixme:ntdll:NtLockFile I/O completion on lock not implemented yet fixme:advapi:SetNamedSecurityInfoW L"C:\\users\\myUser\\Application Data\\Mozilla\\Firefox\\Profiles\\cn4oy6kh.default\\extensions.ini" 1 536870916 (nil) (nil) 0x13d40c (nil) fixme:imm:ImmReleaseContext (0x20022, 0x13e850): stub fixme:win:EnumDisplayDevicesW ((null),0,0x32ee18,0x00000000), stub! fixme:shell:ApplicationAssociationRegistration_QueryCurrentDefault (0x143b50)->(L"webcal", 1, 1, 0x32c7a0) fixme:shell:ApplicationAssociationRegistration_QueryCurrentDefault (0x143b50)->(L"ircs", 1, 1, 0x32c7a0) fixme:shell:ApplicationAssociationRegistration_QueryCurrentDefault (0x143b50)->(L"mailto", 1, 1, 0x32c7a0) fixme:shell:ApplicationAssociationRegistration_QueryCurrentDefault (0x143b50)->(L"irc", 1, 1, 0x32c7a0) fixme:alsa:AudioSessionControl_SetGroupingParam (0x153050)->({7b0a93ee-05e7-4576-9cc5-64fdf201f303}, (null)) - stub fixme:alsa:AudioSessionControl_SetGroupingParam (0x153050)->({00000000-0000-0000-0000-000000000000}, (null)) - stub fixme:alsa:AudioSessionControl_UnregisterAudioSessionNotification (0x153050)->(0x6311880) - stub wine: Call from 0x7b839cf2 to unimplemented function dwmapi.dll.DwmGetCompositionTimingInfo, aborting fixme:dbghelp:elf_search_auxv can't find symbol in module Unfortunately I don't know what to do from there on...

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  • WCF/webservice architecture question

    - by M.R.
    I have a requirement to create a webservice to expose certain items from a CMS as a web service, and I need some suggestions - the structure of the items is as such: item - field 1 - field 2 - field 3 - field 4 So, one would think that the class for this will be: public class MyItem { public string ItemName { get; set; } public List<MyField> Fields { get; set; } } public class MyField { public string FieldName { get; set; } public string FieldValue { get; set; } //they are always string (except - see below) } This works for when its always one level deep, but sometimes, one of the fields is actually a point to ANOTHER item (MyItem) or multiple MyItem (List<MyItem>), so I thought I would change the structure of MyField as follows, to make FieldValue as object; public class MyField { public string FieldName { get; set; } public object FieldValue { get; set; } //changed to object } So, now, I can put whatever I want in there. This is great in theory, but how will clients consume this? I suspect that when users make a reference to this web service, they won't know which object is being returned in that field? This seems like a not-so-good design. Is there a better approach to this?

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  • I've been hired on as a entry-level game developer at a company and have little/no experience in API programming, what should I expect?

    - by Mr. Geneth
    So, I've been hired on as an entry level game developer with little/no experience working with any API other than Win32. This will be an overall learning experience for me as a person and I have gone over this multiple times with the boss and he has no problem with my inexperience. He says that if I'm not worth it now, I will be later. This gives me confidence, but I still feel that I should know a lot more before tackling this position. I would be stupid to pass it up. This is one of my favorite places to come for advice and help and have tried to just accept this, but it just keeps bothering that I can't go in knowing how to at least do the basics. I want to give the company its money's worth. Ya know? My questions are: What should I expect from the other programmers in this project (In terms of patience with me and working together, and being taught)? Is this normal? Any other advice on this sort of thing would be wonderful. I just want to feel comfortable with it.

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  • How to determine if you should use full or differential backup?

    - by Peter Larsson
    Or ask yourself, "How much of the database has changed since last backup?". Here is a simple script that will tell you how much (in percent) have changed in the database since last backup. -- Prepare staging table for all DBCC outputs DECLARE @Sample TABLE         (             Col1 VARCHAR(MAX) NOT NULL,             Col2 VARCHAR(MAX) NOT NULL,             Col3 VARCHAR(MAX) NOT NULL,             Col4 VARCHAR(MAX) NOT NULL,             Col5 VARCHAR(MAX)         )   -- Some intermediate variables for controlling loop DECLARE @FileNum BIGINT = 1,         @PageNum BIGINT = 6,         @SQL VARCHAR(100),         @Error INT,         @DatabaseName SYSNAME = 'Yoda'   -- Loop all files to the very end WHILE 1 = 1     BEGIN         BEGIN TRY             -- Build the SQL string to execute             SET     @SQL = 'DBCC PAGE(' + QUOTENAME(@DatabaseName) + ', ' + CAST(@FileNum AS VARCHAR(50)) + ', '                             + CAST(@PageNum AS VARCHAR(50)) + ', 3) WITH TABLERESULTS'               -- Insert the DBCC output in the staging table             INSERT  @Sample                     (                         Col1,                         Col2,                         Col3,                         Col4                     )             EXEC    (@SQL)               -- DCM pages exists at an interval             SET    @PageNum += 511232         END TRY           BEGIN CATCH             -- If error and first DCM page does not exist, all files are read             IF @PageNum = 6                 BREAK             ELSE                 -- If no more DCM, increase filenum and start over                 SELECT  @FileNum += 1,                         @PageNum = 6         END CATCH     END   -- Delete all records not related to diff information DELETE FROM    @Sample WHERE   Col1 NOT LIKE 'DIFF%'   -- Split the range UPDATE  @Sample SET     Col5 = PARSENAME(REPLACE(Col3, ' - ', '.'), 1),         Col3 = PARSENAME(REPLACE(Col3, ' - ', '.'), 2)   -- Remove last paranthesis UPDATE  @Sample SET     Col3 = RTRIM(REPLACE(Col3, ')', '')),         Col5 = RTRIM(REPLACE(Col5, ')', ''))   -- Remove initial information about filenum UPDATE  @Sample SET     Col3 = SUBSTRING(Col3, CHARINDEX(':', Col3) + 1, 8000),         Col5 = SUBSTRING(Col5, CHARINDEX(':', Col5) + 1, 8000)   -- Prepare data outtake ;WITH cteSource(Changed, [PageCount]) AS (     SELECT      Changed,                 SUM(COALESCE(ToPage, FromPage) - FromPage + 1) AS [PageCount]     FROM        (                     SELECT CAST(Col3 AS INT) AS FromPage,                             CAST(NULLIF(Col5, '') AS INT) AS ToPage,                             LTRIM(Col4) AS Changed                     FROM    @Sample                 ) AS d     GROUP BY    Changed     WITH ROLLUP ) -- Present the final result SELECT  COALESCE(Changed, 'TOTAL PAGES') AS Changed,         [PageCount],         100.E * [PageCount] / SUM(CASE WHEN Changed IS NULL THEN 0 ELSE [PageCount] END) OVER () AS Percentage FROM    cteSource

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  • How to make creating viewmodels at runtime less painful

    - by Mr Happy
    I apologize for the long question, it reads a bit as a rant, but I promise it's not! I've summarized my question(s) below In the MVC world, things are straightforward. The Model has state, the View shows the Model, and the Controller does stuff to/with the Model (basically), a controller has no state. To do stuff the Controller has some dependencies on web services, repository, the lot. When you instantiate a controller you care about supplying those dependencies, nothing else. When you execute an action (method on Controller), you use those dependencies to retrieve or update the Model or calling some other domain service. If there's any context, say like some user wants to see the details of a particular item, you pass the Id of that item as parameter to the Action. Nowhere in the Controller is there any reference to any state. So far so good. Enter MVVM. I love WPF, I love data binding. I love frameworks that make data binding to ViewModels even easier (using Caliburn Micro a.t.m.). I feel things are less straightforward in this world though. Let's do the exercise again: the Model has state, the View shows the ViewModel, and the ViewModel does stuff to/with the Model (basically), a ViewModel does have state! (to clarify; maybe it delegates all the properties to one or more Models, but that means it must have a reference to the model one way or another, which is state in itself) To do stuff the ViewModel has some dependencies on web services, repository, the lot. When you instantiate a ViewModel you care about supplying those dependencies, but also the state. And this, ladies and gentlemen, annoys me to no end. Whenever you need to instantiate a ProductDetailsViewModel from the ProductSearchViewModel (from which you called the ProductSearchWebService which in turn returned IEnumerable<ProductDTO>, everybody still with me?), you can do one of these things: call new ProductDetailsViewModel(productDTO, _shoppingCartWebService /* dependcy */);, this is bad, imagine 3 more dependencies, this means the ProductSearchViewModel needs to take on those dependencies as well. Also changing the constructor is painful. call _myInjectedProductDetailsViewModelFactory.Create().Initialize(productDTO);, the factory is just a Func, they are easily generated by most IoC frameworks. I think this is bad because Init methods are a leaky abstraction. You also can't use the readonly keyword for fields that are set in the Init method. I'm sure there are a few more reasons. call _myInjectedProductDetailsViewModelAbstractFactory.Create(productDTO); So... this is the pattern (abstract factory) that is usually recommended for this type of problem. I though it was genius since it satisfies my craving for static typing, until I actually started using it. The amount of boilerplate code is I think too much (you know, apart from the ridiculous variable names I get use). For each ViewModel that needs runtime parameters you'll get two extra files (factory interface and implementation), and you need to type the non-runtime dependencies like 4 extra times. And each time the dependencies change, you get to change it in the factory as well. It feels like I don't even use a DI container anymore. (I think Castle Windsor has some kind of solution for this [with it's own drawbacks, correct me if I'm wrong]). do something with anonymous types or dictionary. I like my static typing. So, yeah. Mixing state and behavior in this way creates a problem which don't exist at all in MVC. And I feel like there currently isn't a really adequate solution for this problem. Now I'd like to observe some things: People actually use MVVM. So they either don't care about all of the above, or they have some brilliant other solution. I haven't found an in-depth example of MVVM with WPF. For example, the NDDD-sample project immensely helped me understand some DDD concepts. I'd really like it if someone could point me in the direction of something similar for MVVM/WPF. Maybe I'm doing MVVM all wrong and I should turn my design upside down. Maybe I shouldn't have this problem at all. Well I know other people have asked the same question so I think I'm not the only one. To summarize Am I correct to conclude that having the ViewModel being an integration point for both state and behavior is the reason for some difficulties with the MVVM pattern as a whole? Is using the abstract factory pattern the only/best way to instantiate a ViewModel in a statically typed way? Is there something like an in depth reference implementation available? Is having a lot of ViewModels with both state/behavior a design smell?

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