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  • Minimizing Dependencies For GUIs

    - by tuba09
    I've been working on a project, and have been charged with designing the projects GUI front-end. I'm coding in Java and using the Swing toolkit. Usability-wise, the GUI front-end follows all of Nielsen's heuristics. Users can easily get to where they want to go through the click of a button / JComboBox. Essentially, in Swing terms, what happens is their actions drive the creation/deletion of custom panels. The GUI is coming along fine for the most part. However, I have to admit to being utterly dismayed at the tight web of dependencies my code is being smothered in. The main problem that I've encountered, that I haven't been able to fix as of yet, is how to keep a reference to the panels/buttons being changed. I'll give an example: Say there's a button A Say there's a panel B displaying picture C Say there's another picture D (not currently being displayed by panel B) When user clicks A, panel B should remove picture C and display picture D My question is, what's the best way of keeping track of panel B? Since I need a global point of access to panel B, my solution has so far been to just shoehorn it into a static variable, and access it through a series of static getters and setters. And this static variable is usually stored in the reference's original class. I.e. UserPanel has a static variable that stores a reference to itself. Is there an easy, tried-and-true way of dealing with these kinds of situations? Like my GUI works fine, but it is not modular and/or robust at all. To add to this, the dreaded 'cyclical dependencies' issue that's shunned by so many programmers is out here in full effect. I'm fairly new to development and just want to make sure that my code will be fairly extensible and won't cause much of a headache to the next person that decides to get a try at it. I know there's loads of books out there that probably have a nice elegant solution to this, but unfortunately I just don't have the time to leisure read right now. I need something that's quick and dirty. Thanks in advance

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  • Parenting Opengl with Groups in LibGDX

    - by Rudy_TM
    I am trying to make an object child of a Group, but this object has a draw method that calls opengl to draw in the screen. Its class its this public class OpenGLSquare extends Actor { private static final ImmediateModeRenderer renderer = new ImmediateModeRenderer10(); private static Matrix4 matrix = null; private static Vector2 temp = new Vector2(); public static void setMatrix4(Matrix4 mat) { matrix = mat; } @Override public void draw(SpriteBatch batch, float arg1) { // TODO Auto-generated method stub renderer.begin(matrix, GL10.GL_TRIANGLES); renderer.color(color.r, color.g, color.b, color.a); renderer.vertex(x0, y0, 0f); renderer.color(color.r, color.g, color.b, color.a); renderer.vertex(x0, y1, 0f); renderer.color(color.r, color.g, color.b, color.a); renderer.vertex(x1, y1, 0f); renderer.color(color.r, color.g, color.b, color.a); renderer.vertex(x1, y1, 0f); renderer.color(color.r, color.g, color.b, color.a); renderer.vertex(x1, y0, 0f); renderer.color(color.r, color.g, color.b, color.a); renderer.vertex(x0, y0, 0f); renderer.end(); } } In my screen class I have this, i call it in the constructor MyGroupClass spriteLab = new MyGroupClass(spriteSheetLab); OpenGLSquare square = new OpenGLSquare(); square.setX0(100); square.setY0(200); square.setX1(400); square.setY1(280); square.color.set(Color.BLUE); square.setSize(); //spriteLab.addActorAt(0, clock); spriteLab.addActor(square); stage.addActor(spriteLab); And the render in the screen I have @Override public void render(float arg0) { this.gl.glClear(GL10.GL_COLOR_BUFFER_BIT |GL10.GL_DEPTH_BUFFER_BIT); stage.draw(); stage.act(Gdx.graphics.getDeltaTime()); } The problem its that when i use opengl with parent, it resets all the other chldren to position 0,0 and the opengl renderer paints the square in the exact position of the screen and not relative to the parent. I tried using batch.enableBlending() and batch.disableBlending() that fixes the position problem of the other children, but not the relative position of the opengl drawing and it also puts alpha to the glDrawing. What am i doing wrong?:/

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  • Problem Loading a DLL (4 replies)

    I'm having some issues now that I can't see what I'm doing wrong. I'm Pinvoking a non WindowsAPI DLL (I mean, not a dll provided on windows). Pinvoking LoadLibrary, I can get a IntPtr to any WindowsAPI DLL, but never I can get a pointer to my DLL. The code I'm using is very simple, like this one: [DllImport(&quot;kernel32.dll&quot;, SetLastError true)] public static extern IntPtr LoadLibrary(); static void ...

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  • Multi subnet in ubuntu with dnsmasq

    - by Fox Mulder
    I have a multi lan port box that install ubuntu server 11.10. I am setup network in /etc/network/interfaces file as follow: auto lo iface lo inet loopback auto eth0 iface eth0 inet static      address 192.168.128.254      netmask 255.255.255.0      network 192.168.128.0      broadcast 192.168.128.255      gateway 192.168.128.1      dns-nameservers xxxxxx auto eth1 iface eth1 inet static      address 192.168.11.1      netmask 255.255.255.0      network 192.168.11.0      broadcast 192.168.11.255 auto eth2 iface eth2 inet static      address 192.168.21.1      netmask 255.255.255.0      network 192.168.21.0      broadcast 192.168.21.255 auto eth3 iface eth3 inet static      address 192.168.31.1      netmask 255.255.255.0      network 192.168.31.0      broadcast 192.168.31.255 I am also enable the ip forward by echo 1 /proc/sys/net/ipv4/if_forward in rc.local. my dnsmasq config as follow except-interface=eth0 dhcp-range=interface:eth1,set:wifi,192.168.11.101,192.168.11.200,255.255.255.0 dhcp-range=interface:eth2,set:kids,192.168.21.101,192.168.21.200,255.255.255.0 dhcp-range=interface:eth3,set:game,192.168.31.101,192.168.31.200,255.255.255.0 the dhcp was working fine in eth1,eth2,eth3, any machine plug in the subnet can get correct subnet's ip. My problem was, each subnet machine can't ping each other. for example. 192.168.11.101 can't ping 192.168.21.101 but can ping 192.168.128.1 192.168.31.101 can't ping 192.168.21.101 but can ping 192.168.128.1 I am also try to using route add -net 192.168.11.0 netmask 255.255.255.0 gw 192.168.11.1 (and also 192.168.21.0/192.168.31.0) at this multi-lan-port machine. But still won't work. Does anyone can help ? Thanks.

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  • Where to buy a domain for my local server [closed]

    - by Pradyut Bhattacharya
    I have made a website and hosted in my local computer using a static ip Where can i buy a domain name such as www.something.com such that it can redirect to my static IP. So that if i m using a page like a http://localhost/index.jsp it can be accessed by http://www.something.com/index.jsp Does it matter if i run the server locally or should I buy a managed web hosting server from a big company if the traffic is low on my site?

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  • Helper methods StartOfMonth and StartOfNextMonth

    - by Michael Freidgeim
    There are couple methods recently added to My DateTimeHelper class     public static DateTime StartOfMonth(this DateTime dateValue)         {             return new DateTime(dateValue.Year,dateValue.Month,1,0,0,0);         }         public static DateTime StartOfNextMonth(this DateTime dateValue)         {             return StartOfMonth(dateValue).AddMonths(1);         }

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  • Extension methods on a null object instance – something you did not know

    - by nmarun
    Extension methods gave developers with a lot of bandwidth to do interesting (read ‘cool’) things. But there are a couple of things that we need to be aware of while using these extension methods. I have a StringUtil class that defines two extension methods: 1: public static class StringUtils 2: { 3: public static string Left( this string arg, int leftCharCount) 4: { 5: if (arg == null ) 6: { 7: throw new ArgumentNullException( "arg" ); 8: } 9: return arg.Substring(0, leftCharCount); 10...(read more)

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  • Entity Framework 5, separating business logic from model - Repository?

    - by bnice7
    I am working on my first public-facing web application and I’m using MVC 4 for the presentation layer and EF 5 for the DAL. The database structure is locked, and there are moderate differences between how the user inputs data and how the database itself gets populated. I have done a ton of reading on the repository pattern (which I have never used) but most of my research is pushing me away from using it since it supposedly creates an unnecessary level of abstraction for the latest versions of EF since repositories and unit-of-work are already built-in. My initial approach is to simply create a separate set of classes for my business objects in the BLL that can act as an intermediary between my Controllers and the DAL. Here’s an example class: public class MyBuilding { public int Id { get; private set; } public string Name { get; set; } public string Notes { get; set; } private readonly Entities _context = new Entities(); // Is this thread safe? private static readonly int UserId = WebSecurity.GetCurrentUser().UserId; public IEnumerable<MyBuilding> GetList() { IEnumerable<MyBuilding> buildingList = from p in _context.BuildingInfo where p.Building.UserProfile.UserId == UserId select new MyBuilding {Id = p.BuildingId, Name = p.BuildingName, Notes = p.Building.Notes}; return buildingList; } public void Create() { var b = new Building {UserId = UserId, Notes = this.Notes}; _context.Building.Add(b); _context.SaveChanges(); // Set the building ID this.Id = b.BuildingId; // Seed 1-to-1 tables with reference the new building _context.BuildingInfo.Add(new BuildingInfo {Building = b}); _context.GeneralInfo.Add(new GeneralInfo {Building = b}); _context.LocationInfo.Add(new LocationInfo {Building = b}); _context.SaveChanges(); } public static MyBuilding Find(int id) { using (var context = new Entities()) // Is this OK to do in a static method? { var b = context.Building.FirstOrDefault(p => p.BuildingId == id && p.UserId == UserId); if (b == null) throw new Exception("Error: Building not found or user does not have access."); return new MyBuilding {Id = b.BuildingId, Name = b.BuildingInfo.BuildingName, Notes = b.Notes}; } } } My primary concern: Is the way I am instantiating my DbContext as a private property thread-safe, and is it safe to have a static method that instantiates a separate DbContext? Or am I approaching this all wrong? I am not opposed to learning up on the repository pattern if I am taking the total wrong approach here.

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  • Checking timeouts made more readable

    - by Markus
    I have several situations where I need to control timeouts in a technical application. Either in a loop or as a simple check. Of course – handling this is really easy, but none of these is looking cute. To clarify, here is some C# (Pseudo) code: private DateTime girlWentIntoBathroom; girlWentIntoBathroom = DateTime.Now; do { // do something } while (girlWentIntoBathroom.AddSeconds(10) > DateTime.Now); or if (girlWentIntoBathroom.AddSeconds(10) > DateTime.Now) MessageBox.Show("Wait a little longer"); else MessageBox.Show("Knock louder"); Now I was inspired by something a saw in Ruby on StackOverflow: Now I’m wondering if this construct can be made more readable using extension methods. My goal is something that can be read like “If girlWentIntoBathroom is more than 10 seconds ago” 1st attempt if (girlWentIntoBathroom > (10).Seconds().Ago()) MessageBox.Show("Wait a little longer"); else MessageBox.Show("Knock louder"); So I wrote an extension for integer that converts the integer into a TimeSpan public static TimeSpan Seconds(this int amount) { return new TimeSpan(0, 0, amount); } After that, I wrote an extension for TimeSpan like this: public static DateTime Ago(this TimeSpan diff) { return DateTime.Now.Add(-diff); } This works fine so far, but has a great disadvantage. The logic is inverted! Since girlWentIntoBathroom is a timestamp in the past, the right side of the equation needs to count backwards: impossible. Just inverting the equation is no solution, because it will invert the read sentence as well. 2nd attempt So I tried something new: if (girlWentIntoBathroom.IsMoreThan(10).SecondsAgo()) MessageBox.Show("Knock louder"); else MessageBox.Show("Wait a little longer"); IsMoreThan() needs to transport the past timestamp as well as the span for the extension SecondsAgo(). It could be: public static DateWithIntegerSpan IsMoreThan(this DateTime baseTime, int span) { return new DateWithIntegerSpan() { Date = baseTime, Span = span }; } Where DateWithIntegerSpan is simply: public class DateWithIntegerSpan { public DateTime Date {get; set;} public int Span { get; set; } } And SecondsAgo() is public static bool SecondsAgo(this DateWithIntegerSpan dateAndSpan) { return dateAndSpan.Date.Add(new TimeSpan(0, 0, dateAndSpan.Span)) < DateTime.Now; } Using this approach, the English sentence matches the expected behavior. But the disadvantage is, that I need a helping class (DateWithIntegerSpan). Has anyone an idea to make checking timeouts look more cute and closer to a readable sentence? Am I a little too insane thinking about something minor like this?

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  • C# Drawing On Separate Thread [migrated]

    - by Zaid
    I have a "public static" class called "DrawTest" and inside is a method public static DrawRandomRectangle(Bitmap g) { } I want to call that method and draw bunches of stuff and then update the pictureBox that uses the image on a separate thread. To simplify, I'm not trying to make anything specific I'm just trying to learn how to draw and update an image inside of a picturebox on a separate thread.

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  • Using extension methods to decrease the surface area of a C# interface

    - by brian_ritchie
    An interface defines a contract to be implemented by one or more classes.  One of the keys to a well-designed interface is defining a very specific range of functionality. The profile of the interface should be limited to a single purpose & should have the minimum methods required to implement this functionality.  Keeping the interface tight will keep those implementing the interface from getting lazy & not implementing it properly.  I've seen too many overly broad interfaces that aren't fully implemented by developers.  Instead, they just throw a NotImplementedException for the method they didn't implement. One way to help with this issue, is by using extension methods to move overloaded method definitions outside of the interface. Consider the following example: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: public interface IFileTransfer 2: { 3: void SendFile(Stream stream, Uri destination); 4: } 5:   6: public static class IFileTransferExtension 7: { 8: public static void SendFile(this IFileTransfer transfer, 9: string Filename, Uri destination) 10: { 11: using (var fs = File.OpenRead(Filename)) 12: { 13: transfer.SendFile(fs, destination); 14: } 15: } 16: } 17:   18: public static class TestIFileTransfer 19: { 20: static void Main() 21: { 22: IFileTransfer transfer = new FTPFileTransfer("user", "pass"); 23: transfer.SendFile(filename, new Uri("ftp://ftp.test.com")); 24: } 25: } In this example, you may have a number of overloads that uses different mechanisms for specifying the source file. The great part is, you don't need to implement these methods on each of your derived classes.  This gives you a better interface and better code reuse.

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  • Problem Loading a DLL (4 replies)

    I'm having some issues now that I can't see what I'm doing wrong. I'm Pinvoking a non WindowsAPI DLL (I mean, not a dll provided on windows). Pinvoking LoadLibrary, I can get a IntPtr to any WindowsAPI DLL, but never I can get a pointer to my DLL. The code I'm using is very simple, like this one: [DllImport(&quot;kernel32.dll&quot;, SetLastError true)] public static extern IntPtr LoadLibrary(); static void ...

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  • Can't ping devices by IP address for devices allocated IPs by DHCP

    - by GiddyUpHorsey
    I have a home network with a Trendnet wireless router and a Windows Domain. The Domain Controller/DNS server is a Windows 2000 Server and is configured to forward queries to DNS servers provided by the ISP. The router provides DHCP and is configured with the Windows 2000 Server as the DNS server. The network has been set up for a couple of years and usually works fine. When I connect iPhones to the network over WiFi, the router can ping the iPhones through its browser based admin interface, but Windows machines that are part of the Windows Domain cannot. A laptop was connected to the network over WiFi that wasn't joined to the domain and it could see the iPhones. The router UI shows that the laptop has a reserved IP allocated via DHCP. All machines either have a static or DHCP allocated IP on the 192.168.0.* subnet. Router - 192.168.0.1 - Static - Wired Windows Domain Controller - 192.168.0.8 - Static - Virtual Windows 7 Workstation - 192.168.0.200 - DHCP Auto - Wired VMWare ESXi Host - 192.168.0.201 - Static? - Wired iPhone 1 - 192.168.0.202 - DHCP Auto - WiFi iPhone 2 - 192.168.0.203 - DHCP Auto - WiFi Windows Vista Laptop - 192.168.0.204 - DHCP Reserved - WiFi Using the Windows 7 machine (200), I try to ping each machine and the only DHCP machine that responds is itself. The other DHCP machines fail with Reply from 192.168.0.200: Destination host unreachable.. Using nslookup fails with *** domain.controller.name can't find 192.168.0.203: Non-existent domain. Using the Windows 2000 Domain Controller (8), I try to ping each machine and the only DHCP machine that responds is the Windows 7 machine (200). Pinging the other DHCP machines fails with Request timed out.. Using nslookup also fails with *** domain.controller.name can't find 192.168.0.203: Non-existent domain. Using the iPhone 2 (203), I try to ping (Network Ping Lite) the machines with static IP addresses and that works fine. When I try to ping the Windows 7 machine (200) it is unable to get a response. How do I configure the DNS server/Windows Domain/Router properly so that the Windows Domain machines can see the IPs allocated via DHCP?

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  • nginx rewrite for /blah/(.*) /$1

    - by skrewler
    I'm migrating from mod_php to nginx. I got everything working except for this rewrite.. I'm just not familiar enough with nginx configuration to know the correct way to do this. I came up with this by looking at a sample on the nginx site. server { server_name test01.www.myhost.com; root /home/vhosts/my_home/blah; access_log /var/log/nginx/blah.access.log; error_log /var/log/nginx/blah.error.log; index index.php; location / { try_files $uri $uri/ @rewrites; } location @rewrites { rewrite ^ /index.php last; rewrite ^/ht/userGreeting.php /js/iFrame/index.php last; rewrite ^/ht/(.*)$ /$1 last; rewrite ^/userGreeting.php$ /js/iFrame/index.php last; rewrite ^/a$ /adminLogin.php last; rewrite ^/boom\/(.*)$ /boom/index.php?q=$1 last; rewrite ^favicon.ico$ favico_ry.ico last; } # This block will catch static file requests, such as images, css, js # The ?: prefix is a 'non-capturing' mark, meaning we do not require # the pattern to be captured into $1 which should help improve performance location ~* \.(?:ico|css|js|gif|jpe?g|png)$ { # Some basic cache-control for static files to be sent to the browser expires max; add_header Pragma public; add_header Cache-Control "public, must-revalidate, proxy-revalidate"; } include php.conf; } The issue I'm having is with this rewrite: rewrite ^ht\/(.*)$ /$1 last; 99% of requests that will hit this rewrite are static files. So I think maybe it's getting sent to the static files section and that's where things are being messed up? I tried adding this but it didn't work: location ~* ^ht\/.*\.(?:ico|css|js|gif|jpe?g|png)$ { # Some basic cache-control for static files to be sent to the browser expires max; add_header Pragma public; add_header Cache-Control "public, must-revalidate, proxy-revalidate"; } Any help would be appreciated. I know the best thing to do would be to just change the references of /ht/whatever.jpg to /whatever.jpg in the code.. but that's not an option for now.

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  • Will spreading your servers load not just consume more recourses

    - by Saif Bechan
    I am running a heavy real-time updating website. The amount of recourses needed per user are quite high, ill give you an example. Setup Every visit The application is php/mysql so on every visit static and dynamic content is loaded. Recourses: apache,php,mysql Every second (no more than a second will just be too long) The website needs to be updated real-time so every second there is an ajax call thats updates the website. Recourses: jQuery,apache,php,mysql Avarage spending for single user (spending one minute and visited 3 pages) Apache: +/- 63 requests / responsess serving static and dynamic content (img,css,js,html) php: +/- 63 requests / responses mysql: +/- 63 requests / responses jquery: +/- 60 requests / responses Optimization I want to optimize this process, but I think that maybe it would be just the same in the end. Before implementing and testing (which will take weeks) I wanted to have some second opinions from you guys. Every visit I want to start off with having nginx in the front and work as a proxy to deliver the static content. Recources: Dynamic: apache,php,mysql Static: nginx This will spread the load on apache a lot. Every Second For the script that loads every second I want to set up Node.js server side javascript with nginx in te front. I want to set it up that jquery makes a request ones a minute, and node.js streams the data to the client every second. Recources: jQuery,nginx,node.js,mysql Avarage spending for single user (spending one minute and visited 3 pages) Nginx: 4 requests / responsess serving mostly static conetent(img,css,js) Apache: 3 requests only the pages php: 3 requests only the pages node.js: 1 request / 60 responses jquery: 1 request / 60 responses mysql: 63 requests / responses Optimization As you can see in the optimisation the load from Apache and PHP are lifted and places on nginx and node.js. These are known for there light footprint and good performance. But I am having my doubts, because there are still 2 programs extra loaded in the memory and they consume cpu. So it it better to have less programs that do the job, or more. Before I am going to spend a lot of time setting this up I would like to know if it will be worth the while.

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  • Tips for maximizing Nginx requests/sec?

    - by linkedlinked
    I'm building an analytics package, and project requirements state that I need to support 1 billion hits per day. Yep, "billion". In other words, no less than 12,000 hits per second sustained, and preferably some room to burst. I know I'll need multiple servers for this, but I'm trying to get maximum performance out of each node before "throwing more hardware at it". Right now, I have the hits-tracking portion completed, and well optimized. I pretty much just save the requests straight into Redis (for later processing with Hadoop). The application is Python/Django with a gunicorn for the gateway. My 2GB Ubuntu 10.04 Rackspace server (not a production machine) can serve about 1200 static files per second (benchmarked using Apache AB against a single static asset). To compare, if I swap out the static file link with my tracking link, I still get about 600 requests per second -- I think this means my tracker is well optimized, because it's only a factor of 2 slower than serving static assets. However, when I benchmark with millions of hits, I notice a few things -- No disk usage -- this is expected, because I've turned off all Nginx logs, and my custom code doesn't do anything but save the request details into Redis. Non-constant memory usage -- Presumably due to Redis' memory managing, my memory usage will gradually climb up and then drop back down, but it's never once been my bottleneck. System load hovers around 2-4, the system is still responsive during even my heaviest benchmarks, and I can still manually view http://mysite.com/tracking/pixel with little visible delay while my (other) server performs 600 requests per second. If I run a short test, say 50,000 hits (takes about 2m), I get a steady, reliable 600 requests per second. If I run a longer test (tried up to 3.5m so far), my r/s degrades to about 250. My questions -- a. Does it look like I'm maxing out this server yet? Is 1,200/s static files nginx performance comparable to what others have experienced? b. Are there common nginx tunings for such high-volume applications? I have worker threads set to 64, and gunicorn worker threads set to 8, but tweaking these values doesn't seem to help or harm me much. c. Are there any linux-level settings that could be limiting my incoming connections? d. What could cause my performance to degrade to 250r/s on long-running tests? Again, the memory is not maxing out during these tests, and HDD use is nil. Thanks in advance, all :)

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  • When constructing a Bitmap with Bitmap.FromHbitmap(), how soon can the original bitmap handle be del

    - by GBegen
    From the documentation of Image.FromHbitmap() at http://msdn.microsoft.com/en-us/library/k061we7x%28VS.80%29.aspx : The FromHbitmap method makes a copy of the GDI bitmap; so you can release the incoming GDI bitmap using the GDIDeleteObject method immediately after creating the new Image. This pretty explicitly states that the bitmap handle can be immediately deleted with DeleteObject as soon as the Bitmap instance is created. Looking at the implementation of Image.FromHbitmap() with Reflector, however, shows that it is a pretty thin wrapper around the GDI+ function, GdipCreateBitmapFromHBITMAP(). There is pretty scant documentation on the GDI+ flat functions, but http://msdn.microsoft.com/en-us/library/ms533971%28VS.85%29.aspx says that GdipCreateBitmapFromHBITMAP() corresponds to the Bitmap::Bitmap() constructor that takes an HBITMAP and an HPALETTE as parameters. The documentation for this version of the Bitmap::Bitmap() constructor at http://msdn.microsoft.com/en-us/library/ms536314%28VS.85%29.aspx has this to say: You are responsible for deleting the GDI bitmap and the GDI palette. However, you should not delete the GDI bitmap or the GDI palette until after the GDI+ Bitmap::Bitmap object is deleted or goes out of scope. Do not pass to the GDI+ Bitmap::Bitmap constructor a GDI bitmap or a GDI palette that is currently (or was previously) selected into a device context. Furthermore, one can see the source code for the C++ portion of GDI+ in GdiPlusBitmap.h that the Bitmap::Bitmap() constructor in question is itself a wrapper for the GdipCreateBitmapFromHBITMAP() function from the flat API: inline Bitmap::Bitmap( IN HBITMAP hbm, IN HPALETTE hpal ) { GpBitmap *bitmap = NULL; lastResult = DllExports::GdipCreateBitmapFromHBITMAP(hbm, hpal, &bitmap); SetNativeImage(bitmap); } What I can't easily see is the implementation of GdipCreateBitmapFromHBITMAP() that is the core of this functionality, but the two remarks in the documentation seem to be contradictory. The .Net documentation says I can delete the bitmap handle immediately, and the GDI+ documentation says the bitmap handle must be kept until the wrapping object is deleted, but both are based on the same GDI+ function. Furthermore, the GDI+ documentation warns against using a source HBITMAP that is currently or previously selected into a device context. While I can understand why the bitmap should not be selected into a device context currently, I do not understand why there is a warning against using a bitmap that was previously selected into a device context. That would seem to prevent use of GDI+ bitmaps that had been created in memory using standard GDI. So, in summary: Does the original bitmap handle need to be kept around until the .Net Bitmap object is disposed? Does the GDI+ function, GdipCreateBitmapFromHBITMAP(), make a copy of the source bitmap or merely hold onto the handle to the original? Why should I not use an HBITMAP that was previously selected into a device context?

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  • can ServiceLocator.Current.GetInstance return null?

    - by mauricio076
    I have this piece of code (or similar) in many of our views: private IEventAggregator eventAggregator; Constructor() { eventAggregator = ServiceLocator.Current.GetInstance<IEventAggregator>(); ... } I read from this post that ServiceLocator.Current can throw NullReferenceException (bad thing on a constructor) but I was wondering if the GetInstance<() method can return null (or some other inconsistent object) making eventAggregator dangerous to use later in other methods. NOTE: I'm quite new to MVVM and WPF

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  • Windsor dependency

    - by jack
    I have a class with constructor like this: public UserRepository(IBlockRepository blockRepos) { } and again, I have another class with the constructor like this: public BlockRepository(IUserRepository userRepo) { } this causes the Windsor error: Castle.MicroKernel.Handlers.HandlerException: Can't create component 'UserRepository' as it has dependencies to be satisfied. UserRepository is waiting for the following dependencies How do I fix this?

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  • Wrapping a pure virtual method with multiple arguments with Boost.Python

    - by fallino
    Hello, I followed the "official" tutorial and others but still don't manage to expose this pure virtual method (getPeptide) : ms_mascotresults.hpp class ms_mascotresults { public: ms_mascotresults(ms_mascotresfile &resfile, const unsigned int flags, double minProbability, int maxHitsToReport, const char * unigeneIndexFile, const char * singleHit = 0); ... virtual ms_peptide getPeptide(const int q, const int p) const = 0; } ms_mascotresults.cpp #include <boost/python.hpp> using namespace boost::python; #include "msparser.hpp" // which includes "ms_mascotresults.hpp" using namespace matrix_science; #include <iostream> #include <sstream> struct ms_mascotresults_wrapper : ms_mascotresults, wrapper<ms_mascotresults> { ms_peptide getPeptide(const int q, const int p) { this->get_override("getPeptide")(q); this->get_override("getPeptide")(p); } }; BOOST_PYTHON_MODULE(ms_mascotresults) { class_<ms_mascotresults_wrapper, boost::noncopyable>("ms_mascotresults") .def("getPeptide", pure_virtual(&ms_mascotresults::getPeptide) ) ; } Here are the bjam's errors : /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:66: error: cannot declare field ‘boost::python::objects::value_holder<ms_mascotresults_wrapper>::m_held’ to be of abstract type ‘ms_mascotresults_wrapper’ ms_mascotresults.cpp:12: note: because the following virtual functions are pure within ‘ms_mascotresults_wrapper’: ... include/ms_mascotresults.hpp:334: note: virtual matrix_science::ms_peptide matrix_science::ms_mascotresults::getPeptide(int, int) const ms_mascotresults.cpp: In constructor ‘ms_mascotresults_wrapper::ms_mascotresults_wrapper()’: ms_mascotresults.cpp:12: error: no matching function for call to ‘matrix_science::ms_mascotresults::ms_mascotresults()’ include/ms_mascotresults.hpp:284: note: candidates are: matrix_science::ms_mascotresults::ms_mascotresults(matrix_science::ms_mascotresfile&, unsigned int, double, int, const char*, const char*) include/ms_mascotresults.hpp:109: note: matrix_science::ms_mascotresults::ms_mascotresults(const matrix_science::ms_mascotresults&) ... /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp: In constructor ‘boost::python::objects::value_holder<Value>::value_holder(PyObject*) [with Value = ms_mascotresults_wrapper]’: /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:137: note: synthesized method ‘ms_mascotresults_wrapper::ms_mascotresults_wrapper()’ first required here /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:137: error: cannot allocate an object of abstract type ‘ms_mascotresults_wrapper’ ms_mascotresults.cpp:12: note: since type ‘ms_mascotresults_wrapper’ has pure virtual functions So I tried to change the constructor's signature by : BOOST_PYTHON_MODULE(ms_mascotresults) { //class_<ms_mascotresults_wrapper, boost::noncopyable>("ms_mascotresults") class_<ms_mascotresults_wrapper, boost::noncopyable>("ms_mascotresults", init<ms_mascotresfile &, const unsigned int, double, int, const char *,const char *>()) .def("getPeptide", pure_virtual(&ms_mascotresults::getPeptide) ) Giving these errors : /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:66: error: cannot declare field ‘boost::python::objects::value_holder<ms_mascotresults_wrapper>::m_held’ to be of abstract type ‘ms_mascotresults_wrapper’ ms_mascotresults.cpp:12: note: because the following virtual functions are pure within ‘ms_mascotresults_wrapper’: include/ms_mascotresults.hpp:334: note: virtual matrix_science::ms_peptide matrix_science::ms_mascotresults::getPeptide(int, int) const ... ms_mascotresults.cpp:24: instantiated from here /usr/local/boost_1_42_0/boost/python/object/value_holder.hpp:137: error: no matching function for call to ‘ms_mascotresults_wrapper::ms_mascotresults_wrapper(matrix_science::ms_mascotresfile&, const unsigned int&, const double&, const int&, const char* const&, const char* const&)’ ms_mascotresults.cpp:12: note: candidates are: ms_mascotresults_wrapper::ms_mascotresults_wrapper(const ms_mascotresults_wrapper&) ms_mascotresults.cpp:12: note: ms_mascotresults_wrapper::ms_mascotresults_wrapper() If I comment the virtual function getPeptide in the .hpp, it builds perfectly with this constructor : class_<ms_mascotresults>("ms_mascotresults", init<ms_mascotresfile &, const unsigned int, double, int, const char *,const char *>() ) So I'm a bit lost...

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  • Getting the right WPF dispatcher in a thread.

    - by Bert
    Hi, In the constructor of an object i need to create a WPF mediaElement object: m_videoMedia = new MediaElement(); but the class can also be instantiated from a other thread so i need to use Dispatcher.Invoke(DispatcherPriority.Normal, (Action)(() => { m_videoMedia = new MediaElement(); })); But how can I get the right dispatcher instance in that constructor :s

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  • .NET asmx web services: serialize object property as string property to support versioning

    - by mcliedtk
    I am in the process of upgrading our web services to support versioning. We will be publishing our versioned web services like so: http://localhost/project/services/1.0/service.asmx http://localhost/project/services/1.1/service.asmx One requirement of this versioning is that I am not allowed to break the original wsdl (the 1.0 wsdl). The challenge lies in how to shepherd the newly versioned classes through the logic that lies behind the web services (this logic includes a number of command and adapter classes). Note that upgrading to WCF is not an option at the moment. To illustrate this, let's consider an example with Blogs and Posts. Prior to the introduction of versions, we were passing concrete objects around instead of interfaces. So an AddPostToBlog command would take in a Post object instead of an IPost. // Old AddPostToBlog constructor. public AddPostToBlog(Blog blog, Post post) { // constructor body } With the introduction of versioning, I would like to maintain the original Post while adding a PostOnePointOne. Both Post and PostOnePointOne will implement the IPost interface (they are not extending an abstract class because that inheritance breaks the wsdl, though I suppose there may be a way around that via some fancy xml serialization tricks). // New AddPostToBlog constructor. public AddPostToBlog(Blog blog, IPost post) { // constructor body } This brings us to my question regarding serialization. The original Post class has an enum property named Type. For various cross-platform compatibility issues, we are changing our enums in our web services to strings. So I would like to do the following: // New IPost interface. public interface IPost { object Type { get; set; } } // Original Post object. public Post { // The purpose of this attribute would be to maintain how // the enum currently is serialized even though now the // type is an object instead of an enum (internally the // object actually is an enum here, but it is exposed as // an object to implement the interface). [XmlMagic(SerializeAsEnum)] object Type { get; set; } } // New version of Post object public PostOnePointOne { // The purpose of this attribute would be to force // serialization as a string even though it is an object. [XmlMagic(SerializeAsString)] object Type { get; set; } } The XmlMagic refers to an XmlAttribute or some other part of the System.Xml namespace that would allow me to control the type of the object property being serialized (depending on which version of the object I am serializaing). Does anyone know how to accomplish this?

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  • googletest and EXPECT_THROW weirdness

    - by thumper
    I have a class that has no default constructor, but the construct may throw. I was wanting to have a test like: EXPECT_THROW(MyClass(param), std::runtime_error); But the compiler, g++, complains that there is no default constructor for Myclass. However the following: EXPECT_THROW(MyClass foo(param), std::runtime_error); Works, and the test passes as expected. Why though won't googletest accept the temporary object?

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  • Can't make my WCF extension work

    - by Sergio Romero
    I have a WCF solution that consists of the following class libraries: Exercise.Services: Contains the implementation classes for the services. Exercise.ServiceProxy: Contains the classes that are instantiated in the client. Exercise.HttpHost: Contains the services (*.svc files). I'm calling the service from a console application and the "first version" works really well so I took the next step which is to create a custom ServiceHostFactory, ServiceHost, and InstanceProvider so I can use constructor injection in my services as it is explained in this article. These classes are implemented in yet another class library: 4. Exercise.StructureMapWcfExtension Now even though I've modified my service this: <%@ ServiceHost Language="C#" Debug="true" Factory="Exercise.StructureMapWcfExtension.StructureMapServiceHostFactory" Service="Exercise.Services.PurchaseOrderService" %> I always get the following exception: System.ServiceModel.CommunicationException Security negotiation failed because the remote party did not send back a reply in a timely manner. This may be because the underlying transport connection was aborted. It fails in this line of code: public class PurchaseOrderProxy : ClientBase<IPurchaseOrderService>, IPurchaseOrderService { public PurchaseOrderResponse CreatePurchaseOrder(PurchaseOrderRequest purchaseOrderRequest) { return base.Channel.CreatePurchaseOrder(purchaseOrderRequest); //Fails here } } But that is not all, I added a trace to the web.config file and this is the error that appears in the log file: System.InvalidOperationException The service type provided could not be loaded as a service because it does not have a default (parameter-less) constructor. To fix the problem, add a default constructor to the type, or pass an instance of the type to the host. So this means that my ServiceHostFactory is never being hit, I even set a breakpoint in both its constructor and its method and they never get hit. I've added a reference of the StructureMapWcfExtension library to all the other ones (even the console client), one by one to no avail. I also tried to use the option in the host's web.config file to configure the factory like so: <serviceHostingEnvironment> <serviceActivations> <add service="Exercise.Services.PurchaseOrderService" relativeAddress="PurchaseOrderService.svc" factory="Exercise.StructureMapWcfExtension.StructureMapServiceHostFactory"/> </serviceActivations> </serviceHostingEnvironment> That didn't work either. Please I need help in getting this to work so I can incorporate it to our project. Thank you. UPDATE: Here's the service host factory's code: namespace Exercise.StructureMapWcfExtension { public class StructureMapServiceHostFactory : ServiceHostFactory { private readonly Container Container; public StructureMapServiceHostFactory() { Container = new Container(); new ContainerConfigurer().Configure(Container); } protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses) { return new StructureMapServiceHost(Container, serviceType, baseAddresses); } } public class ContainerConfigurer { public void Configure(Container container) { container.Configure(r => r.For<IPurchaseOrderFacade>().Use<PurchaseOrderFacade>()); } } }

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  • how does object programming work?

    - by venom
    Hello, I am not sure about some things in oop. If I have Class1, which has some private field, for example private Field field1, and make getField1(){return field1;} then I have some class with constructor public Class2(Field field){someMethod(field);} And then I call constructor of Class2 in Class3 like: Class2 cl = new Class2(instanceOfClass1.getField1()); And now the question: Am I working with field1 of instanceOfClass1 in "someMethod(field)"?

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