epm performance tuning - Page 528

Need some help understanding IO Statistics

- by Abe Miessler

I have a query that has a very costly INDEX SEEK operation in the execution plan. In order to track down the cause i set IO STATISTICS on and ran it. In the problem section it gave the following statistics: Table '#TempStudents_Enrollment2_____________________________________000000004D5F'. Scan count 0, logical reads 60, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#TempRace2______________________________________________000000004D58'. Scan count 1, logical reads 1, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table 'RefRace'. Scan count 120, logical reads 240, physical reads 1, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table 'RefFedEnctyRaceCatg'. Scan count 18, logical reads 36, physical reads 2, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#43B0BA0F'. Scan count 1, logical reads 60, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#42BC95D6'. Scan count 1, logical reads 60, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#41C8719D'. Scan count 1, logical reads 60, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#40D44D64'. Scan count 1, logical reads 60, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#LEA2_________________________________________________000000004D56'. Scan count 1, logical reads 60, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#39332B9C'. Scan count 1, logical reads 60, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#School2________________________________________________000000004D57'. Scan count 1, logical reads 29164, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#GenderKey______________________________________________000000004D5A'. Scan count 1, logical reads 29164, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#LangAcqKey_____________________________________________000000004D5B'. Scan count 1, logical reads 29164, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#TransferCatKey___________________________________________000000004D5C'. Scan count 1, logical reads 29164, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#ResCatKey______________________________________________000000004D5D'. Scan count 1, logical reads 29164, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table 'RPT_SnapShot_1_4_StuPgm_Denorm'. Scan count 2344954, logical reads 4992518, physical reads 16, read-ahead reads 8, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#3FE0292B'. Scan count 1, logical reads 2344954, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table 'RPT_SnapShot_1_4_StuEnrlmt_Denorm'. Scan count 20, logical reads 87679, physical reads 0, read-ahead reads 87425, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table '#GradeKey_______________________________________________000000004D59'. Scan count 1, logical reads 1, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. What should I look for in here when i'm looking to improve the performance? The line with over 2 million for the Scan count looked suspicious to me but I really don't know. Does anyone see anything here that i should look into in more detail?

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Convert XML namespace prefixes with C#?

- by jrista

I have run into an exasperating problem getting a Java service client to communicate successfully with a WCF service. I have overcome many hurdles, and I believe that this is my last one. The problem boils down to how Java Axis + WSS4J seem to handle xml namespaces. The Java platform seem to be very rigid in what they expect for xml namespace prefixes, and as such, do not understand the WCF reply messages. My problem in a nutshell is as follows. I have an xml response similar to the following from my WCF service: <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" xmlns:a="http://www.w3.org/2005/08/addressing" xmlns:u="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> <s:Header> <a:Action s:mustUnderstand="1" u:Id="_3">http://tempuri.org/IProcessor/DoProcessingResponse</a:Action> <h:CorrelationID xmlns:h="http://tempuri.org/">1234</h:CorrelationID> <a:RelatesTo u:Id="_4">uuid:40f800a0-9613-4f4a-96c5-b9fd98085deb</a:RelatesTo> <o:Security s:mustUnderstand="1" xmlns:o="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">  </o:Security> </s:Header> <s:Body u:Id="_1"> <e:EncryptedData Id="_2" Type="http://www.w3.org/2001/04/xmlenc#Content" xmlns:e="http://www.w3.org/2001/04/xmlenc#"> <e:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes128-cbc"/> <e:CipherData> <e:CipherValue>NfA6XunmyLlT2ucA+5QneoawHm+imcaCltDAJC1mRZOSxoB6YGpDLY1FyVykPbPGDoFGUESLsmvvbD62sNnRrgE+AuKPo+1CD3DF4LfurRcEv9A50ba9V+ViqlrhydhK</e:CipherValue> </e:CipherData> </e:EncryptedData> </s:Body> </s:Envelope> This response uses simple one-character namespace prefixes for most things, such as 's' for SOAP Envelope, 'a' for WS-Addressing, 'o' for 'WS-Security', etc. The Java client, namely WSS4J, seems to expect the following: <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:wsa="http://www.w3.org/2005/08/addressing" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> <soap:Header> <wsa:Action soap:mustUnderstand="1" wsu:Id="_3">http://tempuri.org/IProcessor/DoProcessingResponse</wsa:Action> <h:CorrelationID xmlns:h="http://tempuri.org/">1234</h:CorrelationID> <wsa:RelatesTo wsu:Id="_4">uuid:40f800a0-9613-4f4a-96c5-b9fd98085deb</a:RelatesTo> <wsse:Security soap:mustUnderstand="1" xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">  </wsse:Security> </soap:Header> <soap:Body u:Id="_1"> <xenc:EncryptedData Id="_2" Type="http://www.w3.org/2001/04/xmlenc#Content" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"> <xenc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes128-cbc"/> <xenc:CipherData> <xenc:CipherValue>NfA6XunmyLlT2ucA+5QneoawHm+imcaCltDAJC1mRZOSxoB6YGpDLY1FyVykPbPGDoFGUESLsmvvbD62sNnRrgE+AuKPo+1CD3DF4LfurRcEv9A50ba9V+ViqlrhydhK</xenc:CipherValue> </xenc:CipherData> </xenc:EncryptedData> </soap:Body> </soap:Envelope> Upon receipt of my response message, the Java client and WSS4J seem to want to look up elements by their own internal xml aliases, such as 'wsa' for WS-Addressing, and 'wsse' for WS-Security Extensions. Since neither of those namespaces are present in the actual response xml, exceptions are thrown. I am wondering if there is any simple way to transform an xml document from one set of namespaces to another set using C#, .NET, and the System.Xml namespace. I've poked around with XmlNamespaceManager a bit, but it does not seem to fully support what I need...or at least, I have been unable to find any really useful examples, and am not fully sure how it works. I am trying to avoid having to write some heavy-duty process to handle this manually myself, as I do not want to drastically impact the performance of our services when called by a Java Axis/WSS4J client.

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Approaches for generic, compile-time safe lazy-load methods

- by Aaronaught

Suppose I have created a wrapper class like the following: public class Foo : IFoo { private readonly IFoo innerFoo; public Foo(IFoo innerFoo) { this.innerFoo = innerFoo; } public int? Bar { get; set; } public int? Baz { get; set; } } The idea here is that the innerFoo might wrap data-access methods or something similarly expensive, and I only want its GetBar and GetBaz methods to be invoked once. So I want to create another wrapper around it, which will save the values obtained on the first run. It's simple enough to do this, of course: int IFoo.GetBar() { if ((Bar == null) && (innerFoo != null)) Bar = innerFoo.GetBar(); return Bar ?? 0; } int IFoo.GetBaz() { if ((Baz == null) && (innerFoo != null)) Baz = innerFoo.GetBaz(); return Baz ?? 0; } But it gets pretty repetitive if I'm doing this with 10 different properties and 30 different wrappers. So I figured, hey, let's make this generic: T LazyLoad<T>(ref T prop, Func<IFoo, T> loader) { if ((prop == null) && (innerFoo != null)) prop = loader(innerFoo); return prop; } Which almost gets me where I want, but not quite, because you can't ref an auto-property (or any property at all). In other words, I can't write this: int IFoo.GetBar() { return LazyLoad(ref Bar, f => f.GetBar()); // <--- Won't compile } Instead, I'd have to change Bar to have an explicit backing field and write explicit getters and setters. Which is fine, except for the fact that I end up writing even more redundant code than I was writing in the first place. Then I considered the possibility of using expression trees: T LazyLoad<T>(Expression<Func<T>> propExpr, Func<IFoo, T> loader) { var memberExpression = propExpr.Body as MemberExpression; if (memberExpression != null) { // Use Reflection to inspect/set the property } } This plays nice with refactoring - it'll work great if I do this: return LazyLoad(f => f.Bar, f => f.GetBar()); But it's not actually safe, because someone less clever (i.e. myself in 3 days from now when I inevitably forget how this is implemented internally) could decide to write this instead: return LazyLoad(f => 3, f => f.GetBar()); Which is either going to crash or result in unexpected/undefined behaviour, depending on how defensively I write the LazyLoad method. So I don't really like this approach either, because it leads to the possibility of runtime errors which would have been prevented in the first attempt. It also relies on Reflection, which feels a little dirty here, even though this code is admittedly not performance-sensitive. Now I could also decide to go all-out and use DynamicProxy to do method interception and not have to write any code, and in fact I already do this in some applications. But this code is residing in a core library which many other assemblies depend on, and it seems horribly wrong to be introducing this kind of complexity at such a low level. Separating the interceptor-based implementation from the IFoo interface by putting it into its own assembly doesn't really help; the fact is that this very class is still going to be used all over the place, must be used, so this isn't one of those problems that could be trivially solved with a little DI magic. The last option I've already thought of would be to have a method like: T LazyLoad<T>(Func<T> getter, Action<T> setter, Func<IFoo, T> loader) { ... } This option is very "meh" as well - it avoids Reflection but is still error-prone, and it doesn't really reduce the repetition that much. It's almost as bad as having to write explicit getters and setters for each property. Maybe I'm just being incredibly nit-picky, but this application is still in its early stages, and it's going to grow substantially over time, and I really want to keep the code squeaky-clean. Bottom line: I'm at an impasse, looking for other ideas. Question: Is there any way to clean up the lazy-loading code at the top, such that the implementation will: Guarantee compile-time safety, like the ref version; Actually reduce the amount of code repetition, like the Expression version; and Not take on any significant additional dependencies? In other words, is there a way to do this just using regular C# language features and possibly a few small helper classes? Or am I just going to have to accept that there's a trade-off here and strike one of the above requirements from the list?

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Is there an equivalent to Java's ClassFileTransformer in .NET? (a way to replace a class)

- by Alix

I've been searching for this for quite a while with no luck so far. Is there an equivalent to Java's ClassFileTransformer in .NET? Basically, I want to create a class CustomClassFileTransformer (which in Java would implement the interface ClassFileTransformer) that gets called whenever a class is loaded, and is allowed to tweak it and replace it with the tweaked version. I know there are frameworks that do similar things, but I was looking for something more straightforward, like implementing my own ClassFileTransformer. Is it possible? EDIT #1. More details about why I need this: Basically, I have a C# application and I need to monitor the instructions it wants to run in order to detect read or write operations to fields (operations Ldfld and Stfld) and insert some instructions before the read/write takes place. I know how to do this (except for the part where I need to be invoked to replace the class): for every method whose code I want to monitor, I must: Get the method's MethodBody using MethodBase.GetMethodBody() Transform it to byte array with MethodBody.GetILAsByteArray(). The byte[] it returns contains the bytecode. Analyse the bytecode as explained here, possibly inserting new instructions or deleting/modifying existing ones by changing the contents of the array. Create a new method and use the new bytecode to create its body, with MethodBuilder.CreateMethodBody(byte[] il, int count), where il is the array with the bytecode. I put all these tweaked methods in a new class and use the new class to replace the one that was originally going to be loaded. An alternative to replacing classes would be somehow getting notified whenever a method is invoked. Then I'd replace the call to that method with a call to my own tweaked method, which I would tweak only the first time is invoked and then I'd put it in a dictionary for future uses, to reduce overhead (for future calls I'll just look up the method and invoke it; I won't need to analyse the bytecode again). I'm currently investigating ways to do this and LinFu looks pretty interesting, but if there was something like a ClassFileTransformer it would be much simpler: I just rewrite the class, replace it, and let the code run without monitoring anything. An additional note: the classes may be sealed. I want to be able to replace any kind of class, I cannot impose restrictions on their attributes. EDIT #2. Why I need to do this at runtime. I need to monitor everything that is going on so that I can detect every access to data. This applies to the code of library classes as well. However, I cannot know in advance which classes are going to be used, and even if I knew every possible class that may get loaded it would be a huge performance hit to tweak all of them instead of waiting to see whether they actually get invoked or not. POSSIBLE (BUT PRETTY HARDCORE) SOLUTION. In case anyone is interested (and I see the question has been faved, so I guess someone is), this is what I'm looking at right now. Basically I'd have to implement the profiling API and I'll register for the events that I'm interested in, in my case whenever a JIT compilation starts. An extract of the blogpost: In your ICorProfilerCallback2::ModuleLoadFinished callback, you call ICorProfilerInfo2::GetModuleMetadata to get a pointer to a metadata interface on that module. QI for the metadata interface you want. Search MSDN for "IMetaDataImport", and grope through the table of contents to find topics on the metadata interfaces. Once you're in metadata-land, you have access to all the types in the module, including their fields and function prototypes. You may need to parse metadata signatures and this signature parser may be of use to you. In your ICorProfilerCallback2::JITCompilationStarted callback, you may use ICorProfilerInfo2::GetILFunctionBody to inspect the original IL, and ICorProfilerInfo2::GetILFunctionBodyAllocator and then ICorProfilerInfo2::SetILFunctionBody to replace that IL with your own. The great news: I get notified when a JIT compilation starts and I can replace the bytecode right there, without having to worry about replacing the class, etc. The not-so-great news: you cannot invoke managed code from the API's callback methods, which makes sense but means I'm on my own parsing the IL code, etc, as opposed to be able to use Cecil, which would've been a breeze. I don't think there's a simpler way to do this without using AOP frameworks (such as PostSharp). If anyone has any other idea please let me know. I'm not marking the question as answered yet.

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Using only alphanumeric characters(a-z) inside toCharArray

- by Aaron

Below you will find me using toCharArray in order to send a string to array. I then MOVE the value of the letter using a for statement... for(i = 0; i < letter.length; i++){ letter[i] += (shiftCode); System.out.print(letter[i]); } However, when I use shiftCode to move the value such as... a shifted by -1; I get a symbol @. Is there a way to send the string to shiftCode or tell shiftCode to ONLY use letters? I need it to see my text, like "aaron", and when I use the for statement iterate through a-z only and ignore all symbols and numbers. I THINK it is as simple as... letter=codeWord.toCharArray(a,z); But trying different forms of that and googling it didn't give me any results. Perhaps it has to do with regex or something? Below you will find a complete copy of my program; it works exactly how I want it to do; but it iterates through letters and symbols. I also tried finding instructions online for toCharArray but if there exists any arguments I can't locate them. My program... import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* * Aaron L. Jones * CS219 * AaronJonesProg3 * * This program is designed to - * Work as a Ceasar Cipher */ /** * * Aaron Jones */ public class AaronJonesProg3 { static String codeWord; static int shiftCode; static int i; static char[] letter; /** * @param args the command line arguments */ public static void main(String[] args) throws IOException { // Instantiating that Buffer Class // We are going to use this to read data from the user; in buffer // For performance related reasons BufferedReader reader; // Building the reader variable here // Just a basic input buffer (Holds things for us) reader = new BufferedReader(new InputStreamReader(System.in)); // Java speaks to us here / We get it to query our user System.out.print("Please enter text to encrypt: "); // Try to get their input here try { // Get their codeword using the reader codeWord = reader.readLine(); // Make that input upper case codeWord = codeWord.toUpperCase(); // Cut the white space out codeWord = codeWord.replaceAll("\\s",""); // Make it all a character array letter = codeWord.toCharArray(); } // If they messed up the input we let them know here and end the prog. catch(Throwable t) { System.out.println(t.toString()); System.out.println("You broke it. But you impressed me because" + "I don't know how you did it!"); } // Java Speaks / Lets get their desired shift value System.out.print("Please enter the shift value: "); // Try for their input try { // We get their number here shiftCode = Integer.parseInt(reader.readLine()); } // Again; if the user broke it. We let them know. catch(java.lang.NumberFormatException ioe) { System.out.println(ioe.toString()); System.out.println("How did you break this? Use a number next time!"); } for(i = 0; i < letter.length; i++){ letter[i] += (shiftCode); System.out.print(letter[i]); } System.out.println(); /**************************************************************** **************************************************************** ***************************************************************/ // Java speaks to us here / We get it to query our user System.out.print("Please enter text to decrypt: "); // Try to get their input here try { // Get their codeword using the reader codeWord = reader.readLine(); // Make that input upper case codeWord = codeWord.toUpperCase(); // Cut the white space out codeWord = codeWord.replaceAll("\\s",""); // Make it all a character array letter = codeWord.toCharArray(); } // If they messed up the input we let them know here and end the prog. catch(Throwable t) { System.out.println(t.toString()); System.out.println("You broke it. But you impressed me because" + "I don't know how you did it!"); } // Java Speaks / Lets get their desired shift value System.out.print("Please enter the shift value: "); // Try for their input try { // We get their number here shiftCode = Integer.parseInt(reader.readLine()); } // Again; if the user broke it. We let them know. catch(java.lang.NumberFormatException ioe) { System.out.println(ioe.toString()); System.out.println("How did you break this? Use a number next time!"); } for(i = 0; i < letter.length; i++){ letter[i] += (shiftCode); System.out.print(letter[i]); } System.out.println(); } }

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How to associate Wi-Fi beacon info with a virtual "location"?

- by leander

We have a piece of embedded hardware that will sense 802.11 beacons, and we're using this to make a map of currently visible bssid -> signalStrength. Given this map, we would like to make a determination: Is this likely to be a location I have been to before? If so, what is its ID? If not, I should remember this location: generate a new ID. Now what should I store (and how should I store it) to make future determinations easier? This is for an augmented-reality app/game. We will be using it to associate particular characters and events with "locations". The device does not have internet or cellular access, so using a geolocation service is out of consideration for the time being. (We don't really need to know where we are in reality, just be able to determine if we return there.) It isn't crucial that it be extremely accurate, but it would be nice if it was tolerant to signal strength changes or the occasional missing beacon. It should be usable in relatively low numbers of access points (e.g. rural house with one wireless router) or many (wandering around a dense metropolis). In the case of a city, it should change location every few minutes of walking (continuously-overlapping signals make this a bit more tricky in naive code). A reasonable number of false positives (match a location when we aren't actually there) is acceptable. The wrong character/event showing up just adds a bit of variety. False negatives (no location match) are a bit more troublesome: this will tend to add a better-matching new location to the saved locations, masking the old one. While we will have additional logic to ensure locations that the device hasn't seen in a while will "orphan" any associated characters or events (if e.g. you move to a different country), we'd prefer not to mask and eventually orphan locations you do visit regularly. Some technical complications: signalStrength is returned as 1-4; presumably it's related to dB, but we are not sure exactly how; in my experiments it tends to stick to either 1 or 4, but occasionally we see numbers in between. (Tech docs on the hardware are sparse.) The device completes a scan of one-quarter of the channel space every second; so it takes about 4-5 seconds to get a complete picture of what's around. The list isn't always complete. (We are making strides to fix this using some slight sampling period randomization, as recommended by the library docs. We're also investigating ways to increase the number of scans without killing our performance; the hardware/libs are poorly behaved when it comes to saturating the bus.) We have only kilobytes to store our history. We have a "working" impl now, but it is relatively naive, and flaky in the face of real-world Wi-Fi behavior. Rough pseudocode: // recordLocation() -- only store strength 4 locations m_savedLocations[g_nextId++] = filterForStrengthGE( m_currentAPs, 4 ); // determineLocation() bestPoints = -inf; foreach ( oldLoc in m_savedLocations ) { points = 0.0; foreach ( ap in m_currentAPs ) { if ( oldLoc.has( ap ) ) { switch ( ap.signalStrength ) { case 3: points += 1.0; break; case 4: points += 2.0; break; } } } points /= oldLoc.numAPs; if ( points > bestPoints ) { bestLoc = oldLoc; bestPoints = points; } } if ( bestLoc && bestPoints > 1.0 ) { if ( bestPoints >= (2.0 - epsilon) ) { // near-perfect match. // update location with any new high-strength APs that have appeared bestLoc.addAPs( filterForStrengthGE( m_currentAPs, 4 ) ); } return bestLoc; } else { return NO_MATCH; } We record a location currently only when we have NO_MATCH and the app determines it's time for a new event. (The "near-perfect match" code above would appear to make it harder to match in the future... It's mostly to keep new powerful APs from being associated with other locations, but you'd think we'd need something to counter this if e.g. an AP doesn't show up in the next 10 times I match a location.) I have a feeling that we're missing some things from set theory or graph theory that would assist in grouping/classification of this data, and perhaps providing a better "confidence level" on matches, and better robustness against missed beacons, signal strength changes, and the like. Also it would be useful to have a good method for mutating locations over time. Any useful resources out there for this sort of thing? Simple and/or robust approaches we're missing?

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Making swap faster, easier to use and exception-safe

- by FredOverflow

I could not sleep last night and started thinking about std::swap. Here is the familiar C++98 version: template <typename T> void swap(T& a, T& b) { T c(a); a = b; b = c; } If a user-defined class Foo uses external ressources, this is inefficient. The common idiom is to provide a method void Foo::swap(Foo& other) and a specialization of std::swap<Foo>. Note that this does not work with class templates since you cannot partially specialize a function template, and overloading names in the std namespace is illegal. The solution is to write a template function in one's own namespace and rely on argument dependent lookup to find it. This depends critically on the client to follow the "using std::swap idiom" instead of calling std::swap directly. Very brittle. In C++0x, if Foo has a user-defined move constructor and a move assignment operator, providing a custom swap method and a std::swap<Foo> specialization has little to no performance benefit, because the C++0x version of std::swap uses efficient moves instead of copies: #include <utility> template <typename T> void swap(T& a, T& b) { T c(std::move(a)); a = std::move(b); b = std::move(c); } Not having to fiddle with swap anymore already takes a lot of burden away from the programmer. Current compilers do not generate move constructors and move assignment operators automatically yet, but as far as I know, this will change. The only problem left then is exception-safety, because in general, move operations are allowed to throw, and this opens up a whole can of worms. The question "What exactly is the state of a moved-from object?" complicates things further. Then I was thinking, what exactly are the semantics of std::swap in C++0x if everything goes fine? What is the state of the objects before and after the swap? Typically, swapping via move operations does not touch external resources, only the "flat" object representations themselves. So why not simply write a swap template that does exactly that: swap the object representations? #include <cstring> template <typename T> void swap(T& a, T& b) { unsigned char c[sizeof(T)]; memcpy( c, &a, sizeof(T)); memcpy(&a, &b, sizeof(T)); memcpy(&b, c, sizeof(T)); } This is as efficient as it gets: it simply blasts through raw memory. It does not require any intervention from the user: no special swap methods or move operations have to be defined. This means that it even works in C++98 (which does not have rvalue references, mind you). But even more importantly, we can now forget about the exception-safety issues, because memcpy never throws. I can see two potential problems with this approach: First, not all objects are meant to be swapped. If a class designer hides the copy constructor or the copy assignment operator, trying to swap objects of the class should fail at compile-time. We can simply introduce some dead code that checks whether copying and assignment are legal on the type: template <typename T> void swap(T& a, T& b) { if (false) // dead code, never executed { T c(a); // copy-constructible? a = b; // assignable? } unsigned char c[sizeof(T)]; std::memcpy( c, &a, sizeof(T)); std::memcpy(&a, &b, sizeof(T)); std::memcpy(&b, c, sizeof(T)); } Any decent compiler can trivially get rid of the dead code. (There are probably better ways to check the "swap conformance", but that is not the point. What matters is that it's possible). Second, some types might perform "unusual" actions in the copy constructor and copy assignment operator. For example, they might notify observers of their change. I deem this a minor issue, because such kinds of objects probably should not have provided copy operations in the first place. Please let me know what you think of this approach to swapping. Would it work in practice? Would you use it? Can you identify library types where this would break? Do you see additional problems? Discuss!

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Dynamic object property populator (without reflection)

- by grenade

I want to populate an object's properties without using reflection in a manner similar to the DynamicBuilder on CodeProject. The CodeProject example is tailored for populating entities using a DataReader or DataRecord. I use this in several DALs to good effect. Now I want to modify it to use a dictionary or other data agnostic object so that I can use it in non DAL code --places I currently use reflection. I know almost nothing about OpCodes and IL. I just know that it works well and is faster than reflection. I have tried to modify the CodeProject example and because of my ignorance with IL, I have gotten stuck on two lines. One of them deals with dbnulls and I'm pretty sure I can just lose it, but I don't know if the lines preceding and following it are related and which of them will also need to go. The other, I think, is the one that pulled the value out of the datarecord before and now needs to pull it out of the dictionary. I think I can replace the "getValueMethod" with my "property.Value" but I'm not sure. I'm open to alternative/better ways of skinning this cat too. Here's the code so far (the commented out lines are the ones I'm stuck on): using System; using System.Collections.Generic; using System.Reflection; using System.Reflection.Emit; public class Populator<T> { private delegate T Load(Dictionary<string, object> properties); private Load _handler; private Populator() { } public T Build(Dictionary<string, object> properties) { return _handler(properties); } public static Populator<T> CreateBuilder(Dictionary<string, object> properties) { //private static readonly MethodInfo getValueMethod = typeof(IDataRecord).GetMethod("get_Item", new [] { typeof(int) }); //private static readonly MethodInfo isDBNullMethod = typeof(IDataRecord).GetMethod("IsDBNull", new [] { typeof(int) }); Populator<T> dynamicBuilder = new Populator<T>(); DynamicMethod method = new DynamicMethod("Create", typeof(T), new[] { typeof(Dictionary<string, object>) }, typeof(T), true); ILGenerator generator = method.GetILGenerator(); LocalBuilder result = generator.DeclareLocal(typeof(T)); generator.Emit(OpCodes.Newobj, typeof(T).GetConstructor(Type.EmptyTypes)); generator.Emit(OpCodes.Stloc, result); int i = 0; foreach (var property in properties) { PropertyInfo propertyInfo = typeof(T).GetProperty(property.Key, BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase | BindingFlags.FlattenHierarchy | BindingFlags.Default); Label endIfLabel = generator.DefineLabel(); if (propertyInfo != null && propertyInfo.GetSetMethod() != null) { generator.Emit(OpCodes.Ldarg_0); generator.Emit(OpCodes.Ldc_I4, i); //generator.Emit(OpCodes.Callvirt, isDBNullMethod); generator.Emit(OpCodes.Brtrue, endIfLabel); generator.Emit(OpCodes.Ldloc, result); generator.Emit(OpCodes.Ldarg_0); generator.Emit(OpCodes.Ldc_I4, i); //generator.Emit(OpCodes.Callvirt, getValueMethod); generator.Emit(OpCodes.Unbox_Any, property.Value.GetType()); generator.Emit(OpCodes.Callvirt, propertyInfo.GetSetMethod()); generator.MarkLabel(endIfLabel); } i++; } generator.Emit(OpCodes.Ldloc, result); generator.Emit(OpCodes.Ret); dynamicBuilder._handler = (Load)method.CreateDelegate(typeof(Load)); return dynamicBuilder; } } EDIT: Using Marc Gravell's PropertyDescriptor implementation (with HyperDescriptor) the code is simplified a hundred-fold. I now have the following test: using System; using System.Collections.Generic; using System.ComponentModel; using Hyper.ComponentModel; namespace Test { class Person { public int Id { get; set; } public string Name { get; set; } } class Program { static void Main() { HyperTypeDescriptionProvider.Add(typeof(Person)); var properties = new Dictionary<string, object> { { "Id", 10 }, { "Name", "Fred Flintstone" } }; Person person = new Person(); DynamicUpdate(person, properties); Console.WriteLine("Id: {0}; Name: {1}", person.Id, person.Name); Console.ReadKey(); } public static void DynamicUpdate<T>(T entity, Dictionary<string, object> properties) { foreach (PropertyDescriptor propertyDescriptor in TypeDescriptor.GetProperties(typeof(T))) if (properties.ContainsKey(propertyDescriptor.Name)) propertyDescriptor.SetValue(entity, properties[propertyDescriptor.Name]); } } } Any comments on performance considerations for both TypeDescriptor.GetProperties() & PropertyDescriptor.SetValue() are welcome...

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PHP MVC Framework Structure

- by bigstylee

I am sorry about the amount of code here. I have tried to show enough for understanding while avoiding confusion (I hope). I have included a second copy of the code at Pastebin. (The code does execute without error/notice/warning.) I am currently creating a Content Management System while trying to implement the idea of Model View Controller. I have only recently come across the concept of MVC (within the last week) and trying to implement this into my current project. One of the features of the CMS is dynamic/customisable menu areas and each feature will be represented by a controller. Therefore there will be multiple versions of the Controller Class, each with specific extended functionality. I have looked at a number of tutorials and read some open source solutions to the MVC Framework. I am now trying to create a lightweight solution for my specific requirements. I am not interested in backwards compatibility, I am using PHP 5.3. An advantage of the Base class is not having to use global and can directly access any loaded class using $this->Obj['ClassName']->property/function();. Hoping to get some feedback using the basic structure outlined (with performance in mind). Specifically; a) Have I understood/implemented the concept of MVC correctly? b) Have I understood/implemented Object Orientated techniques with PHP 5 correctly? c) Should the class propertise of Base be static? d) Improvements? Thank you very much in advance! <?php /* A "Super Class" that creates/stores all object instances */ class Base { public static $Obj = array(); // Not sure this is the correct use of the "static" keyword? public static $var; static public function load_class($directory, $class) { echo count(self::$Obj)."\n"; // This does show the array is getting updated and not creating a new array :) if (!isset(self::$Obj[$class]) && !is_object(self::$Obj[$class])) //dont want to load it twice { /* Locate and include the class file based upon name ($class) */ return self::$Obj[$class] = new $class(); } return TRUE; } } /* Loads general configuration objects into the "Super Class" */ class Libraries extends Base { public function __construct(){ $this->load_class('library', 'Database'); $this->load_class('library', 'Session'); self::$var = 'Hello World!'; //testing visibility /* Other general funciton classes */ } } class Database extends Base { /* Connects to the the database and executes all queries */ public function query(){} } class Session extends Base { /* Implements Sessions in database (read/write) */ } /* General functionality of controllers */ abstract class Controller extends Base { protected function load_model($class, $method) { /* Locate and include the model file */ $this->load_class('model', $class); call_user_func(array(self::$Obj[$class], $method)); } protected function load_view($name) { /* Locate and include the view file */ #include('views/'.$name.'.php'); } } abstract class View extends Base { /* ... */ } abstract class Model extends Base { /* ... */ } class News extends Controller { public function index() { /* Displays the 5 most recent News articles and displays with Content Area */ $this->load_model('NewsModel', 'index'); $this->load_view('news', 'index'); echo $this->var; } public function menu() { /* Displays the News Title of the 5 most recent News articles and displays within the Menu Area */ $this->load_model('news/index'); $this->load_view('news/index'); } } class ChatBox extends Controller { /* ... */ } /* Lots of different features extending the controller/view/model class depending upon request and layout */ class NewsModel extends Model { public function index() { echo $this->var; self::$Obj['Database']->query(/*SELECT 5 most recent news articles*/); } public function menu() { /* ... */ } } $Libraries = new Libraries; $controller = 'News'; // Would be determined from Query String $method = 'index'; // Would be determined from Query String $Content = $Libraries->load_class('controller', $controller); //create the controller for the specific page if (in_array($method, get_class_methods($Content))) { call_user_func(array($Content, $method)); } else { die('Bad Request'. $method); } $Content::$var = 'Goodbye World'; echo $Libraries::$var . ' - ' . $Content::$var; ?> /* Ouput */ 0 1 2 3 Goodbye World! - Goodbye World

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PHP Fatal error, trying to request method inside model multiple times

- by Tom

The error message [23-Mar-2010 08:36:16] PHP Fatal error: Cannot redeclare humanize() (previously declared in /Users/tmclssns/Sites/nadar/nadar/trunk/webapp/application/filer/models/Filer/Aggregate.php:133) in /Users/tmclssns/Sites/nadar/nadar/trunk/webapp/application/filer/models/Filer/Aggregate.php on line 133 I have a "Filer" model which contains several methods to generate graphs. Each method in there related to generating graphs has the suffix "Graph" in the method name. As we have some performance issues, I try to render the graphs in advance (using cron) instead of rendering them on each request. The code below is what I came up with: public function generategraphsAction() { $this->_helper->viewRenderer->setNoRender(); $config = Zend_Registry::get('config'); $id = $this->_getParam('filerid'); $filer = new Filer($id); $filer_methods = get_class_methods($filer); foreach ($filer_methods as $filer_method) { if (preg_match('/^(.*)Graph$/i', $filer_method, $matches)) { $path = $config->imaging_caching_dir . "/$id/{$matches[1]}.png"; $filer->$matches[0]($path); } } // var_dump(get_class_methods($filer)); die; } The result from the var_dump(), when uncommented, is: array 0 => string '__construct' (length=11) 1 => string 'find_by_name' (length=12) 2 => string 'getPartner' (length=10) 3 => string 'getSlots' (length=8) 4 => string 'getGroups' (length=9) 5 => string 'grouplist' (length=9) 6 => string 'getAggregates' (length=13) 7 => string 'getVolumes' (length=10) 8 => string 'getAggregateVolumes' (length=19) 9 => string 'getShelves' (length=10) 10 => string 'getAutoSupportHistory' (length=21) 11 => string 'getAutoSupportMail' (length=18) 12 => string 'getOrphans' (length=10) 13 => string 'getAll' (length=6) 14 => string 'getDiskRevOverview' (length=18) 15 => string 'getDiskTypeOverview' (length=19) 16 => string 'getDiskTypeSizeFunctionOverview' (length=31) 17 => string 'getLicenses' (length=11) 18 => string 'removeGroup' (length=11) 19 => string 'addGroup' (length=8) 20 => string 'hasGroup' (length=8) 21 => string 'aggdefaultGraph' (length=15) 22 => string 'aggbarGraph' (length=11) 23 => string 'voldefaultGraph' (length=15) 24 => string 'volbarGraph' (length=11) 25 => string 'replicationGraph' (length=16) 26 => string 'getReplicationData' (length=18) 27 => string 'humanize' (length=8) 28 => string 'getFiler' (length=8) 29 => string 'getOptions' (length=10) 30 => string 'getCifsInfo' (length=11) 31 => string 'getCifsStats' (length=12) 32 => string '__get' (length=5) 33 => string 'tr' (length=2) 34 => string 'trs' (length=3) 35 => string 'fieldList' (length=9) The generategraphsAction() method finds the 'Graph' methods correctly: array 0 => string 'aggdefaultGraph' (length=15) 1 => string 'aggdefault' (length=10) array 0 => string 'aggbarGraph' (length=11) 1 => string 'aggbar' (length=6) array 0 => string 'voldefaultGraph' (length=15) 1 => string 'voldefault' (length=10) array 0 => string 'volbarGraph' (length=11) 1 => string 'volbar' (length=6) array 0 => string 'replicationGraph' (length=16) 1 => string 'replication' (length=11) However when the first graph is generated, it generates the above listed PHP fatal error. Anyone can come up with a solution to this? I tried to pass by reference or switch a few things around (like re declare the Filer model, $current_filer = new Filer($id); and unset() it again after the request, but resulted in the same error) without much success. The referenced method "humanize" isn't used for anything I'm doing at the moment, but belongs to the Model because it's used in several other places. Of course, removing the method is not really an option right now, and the model contains several other methods as well so I assume if I just move the humanize method around, it will generate an error on the next one. For reference, the humanize() method: public function humanize ($kbytes, $unit = null) { // KiloByte, Megabyte, GigaByte, TeraByte, PetaByte, ExaByte, ZettaByte, YottaByte $units = array('KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'); if (null !== $units) { $i = array_search(substr($unit, -2), $units); if (! $i) { $i = floor((strlen($kbytes) - 1) / 3); } } else { $i = floor((strlen($kbytes) - 1) / 3); } $newSize = round($kbytes / pow(1024, $i), 2); return $newSize . $units[$i]; } Thanks in advance for the help offered.

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Help required in adding new methods, properties into existing classes dynamically

- by Bepenfriends

Hi All, I am not sure whether it is possible to achieve this kind of implementation in Dot Net. Below are the information Currently we are on an application which is done in COM+, ASP, XSL, XML technologies. It is a multi tier architecture application in which COM+ acts as the BAL. The execution steps for any CRUD operation will be defined using a seperate UI which uses XML to store the information. BAL reads the XML and understands the execution steps which are defined and executes corresponding methods in DLL. Much like EDM we have our custom model (using XML) which determines which property of object is searchable, retrievable etc. Based on this information BAL constructs queries and calls procedures to get the data. In the current application both BAL and DAL are heavily customizable without doing any code change. the results will be transmitted to presentation layer in XML format which constructs the UI based on the data recieved. Now I am creating a migration project which deals with employee information. It is also going to follow the N Tier architecture in which the presentation layer communicates with BAL which connects to DAL to return the Data. Here is the problem, In our existing version we are handling every information as XML in its native form (no converstion of object etc), but in the migration project, Team is really interested in utilizing the OOP model of development where every information which is sent from BAL need to be converted to objects of its respective types (example employeeCollection, Address Collection etc). If we have the static number of data returned from BAL we can have a class which contains those nodes as properties and we can access the same. But in our case the data returned from our BAL need to be customized. How can we handle the customization in presentation layer which is converting the result to an Object. Below is an example of the XML returned <employees> <employee> <firstName>Employee 1 First Name</firstName> <lastName>Employee 1 Last Name</lastName> <addresses> <address> <addressType>1</addressType> <StreetName>Street name1</StreetName> <RegionName>Region name</RegionName> <address> <address> <addressType>2</addressType> <StreetName>Street name2</StreetName> <RegionName>Region name</RegionName> <address> <address> <addressType>3</addressType> <StreetName>Street name3</StreetName> <RegionName>Region name</RegionName> <address> <addresses> </employee> <employee> <firstName>Employee 2 First Name</firstName> <lastName>Employee 2 Last Name</lastName> <addresses> <address> <addressType>1</addressType> <StreetName>Street name1</StreetName> <RegionName>Region name</RegionName> <address> <address> <addressType>2</addressType> <StreetName>Street name2</StreetName> <RegionName>Region name</RegionName> <address> <addresses> </employee> </employees> If these are the only columns then i can write a class which is like public class Address{ public int AddressType {get;set;}; public string StreetName {get;set;}; public string RegionName {get;set;}; } public class Employee{ public string FirstName {get; set;} public string LastName {get; set;} public string AddressCollection {get; set;} } public class EmployeeCollection : List<Employee>{ public bool Add (Employee Data){ .... } } public class AddressCollection : List<Address>{ public bool Add (Address Data){ .... } } This class will be provided to customers and consultants as DLLs. We will not provide the source code for the same. Now when the consultants or customers does customization(example adding country to address and adding passport information object with employee object) they must be able to access those properties in these classes, but without source code they will not be able to do those modifications.which makes the application useless. Is there is any way to acomplish this in DotNet. I thought of using Anonymous classes but, the problem with Anonymous classes are we can not have methods in it. I am not sure how can i fit the collection objects (which will be inturn an anonymous class) Not sure about datagrid / user control binding etc. I also thought of using CODEDom to create classes runtime but not sure about the meory, performance issues. also the classes must be created only once and must use the same till there is another change. Kindly help me out in this problem. Any kind of help meterial/ cryptic code/ links will be helpful.

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Watching setTimeout loops so that only one is running at a time.

- by DA

I'm creating a content rotator in jQuery. 5 items total. Item 1 fades in, pauses 10 seconds, fades out, then item 2 fades in. Repeat. Simple enough. Using setTimeout I can call a set of functions that create a loop and will repeat the process indefinitely. I now want to add the ability to interrupt this rotator at any time by clicking on a navigation element to jump directly to one of the content items. I originally started going down the path of pinging a variable constantly (say every half second) that would check to see if a navigation element was clicked and, if so, abandon the loop, then restart the loop based on the item that was clicked. The challenge I ran into was how to actually ping a variable via a timer. The solution is to dive into JavaScript closures...which are a little over my head but definitely something I need to delve into more. However, in the process of that, I came up with an alternative option that actually seems to be better performance-wise (theoretically, at least). I have a sample running here: http://jsbin.com/uxupi/14 (It's using console.log so have fireBug running) Sample script: $(document).ready(function(){ var loopCount = 0; $('p#hello').click(function(){ loopCount++; doThatThing(loopCount); }) function doThatOtherThing(currentLoopCount) { console.log('doThatOtherThing-'+currentLoopCount); if(currentLoopCount==loopCount){ setTimeout(function(){doThatThing(currentLoopCount)},5000) } } function doThatThing(currentLoopCount) { console.log('doThatThing-'+currentLoopCount); if(currentLoopCount==loopCount){ setTimeout(function(){doThatOtherThing(currentLoopCount)},5000); } } }) The logic being that every click of the trigger element will kick off the loop passing into itself a variable equal to the current value of the global variable. That variable gets passed back and forth between the functions in the loop. Each click of the trigger also increments the global variable so that subsequent calls of the loop have a unique local variable. Then, within the loop, before the next step of each loop is called, it checks to see if the variable it has still matches the global variable. If not, it knows that a new loop has already been activated so it just ends the existing loop. Thoughts on this? Valid solution? Better options? Caveats? Dangers? UPDATE: I'm using John's suggestion below via the clearTimeout option. However, I can't quite get it to work. The logic is as such: var slideNumber = 0; var timeout = null; function startLoop(slideNumber) { ...do stuff here to set up the slide based on slideNumber... slideFadeIn() } function continueCheck(){ if (timeout != null) { // cancel the scheduled task. clearTimeout(timeout); timeout = null; return false; }else{ return true; } }; function slideFadeIn() { if (continueCheck){ // a new loop hasn't been called yet so proceed... // fade in the LI $currentListItem.fadeIn(fade, function() { if(multipleFeatures){ timeout = setTimeout(slideFadeOut,display); } }); }; function slideFadeOut() { if (continueLoop){ // a new loop hasn't been called yet so proceed... slideNumber=slideNumber+1; if(slideNumber==features.length) { slideNumber = 0; }; timeout = setTimeout(function(){startLoop(slideNumber)},100); }; startLoop(slideNumber); The above kicks of the looping. I then have navigation items that, when clicked, I want the above loop to stop, then restart with a new beginning slide: $(myNav).click(function(){ clearTimeout(timeout); timeout = null; startLoop(thisItem); }) If I comment out 'startLoop...' from the click event, it, indeed, stops the initial loop. However, if I leave that last line in, it doesn't actually stop the initial loop. Why? What happens is that both loops seem to run in parallel for a period. So, when I click my navigation, clearTimeout is called, which clears it.

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New hire expectations... (Am I being unreasonable?)

- by user295841

I work for a very small custom software shop. We currently consist me and my boss. My boss is an old FoxPro DOS developer and OOP makes him uncomfortable. He is planning on taking a back seat in the next few years to hopefully enjoy a “partial retirement”. I will be taking over the day to day operations and we are now desperately looking for more help. We tried Monster.com, Dice.com, and others a few years ago when we started our search. We had no success. We have tried outsourcing overseas (total disaster), hiring kids right out of college (mostly a disaster but that’s where I came from), interns (good for them, not so good for us) and hiring laid off “experienced” developers (there was a reason they were laid off). I have heard hiring practices discussed on podcasts, blogs, etc... and have tried a few. The “Fizz Buzz” test was a good one. One kid looked physically ill before he finally gave up. I think my problem is that I have grown so much as a developer since I started here that I now have a high standard. I hear/read very intelligent people podcasts and blogs and I know that there are lots of people out there that can do the job. I don’t want to settle for less than a “good” developer. Perhaps my expectations are unreasonable. I expect any good developer (entry level or experienced) to be billable (at least paying their own wage) in under one month. I expect any good developer to be able to be productive (at least dangerous) in any language or technology with only a few days of research/training. I expect any good developer to be able to take a project from initial customer request to completion with little or no help from others. Am I being unreasonable? What constitutes a valuable developer? What should be expected of an entry level developer? What should be expected of an experienced developer? I realize that everyone is different but there has to be some sort of expectations standard, right? I have been giving the test project below to potential canidates to weed them out. Good idea? Too much? Too little? Please let me know what you think. Thanks. Project ID: T00001 Description: Order Entry System Deadline: 1 Week Scope The scope of this project is to develop a fully function order entry system. Screen/Form design must be user friendly and promote efficient data entry and modification. User experience (Navigation, Screen/Form layouts, Look and Feel…) is at the developer’s discretion. System may be developed using any technologies that conform to the technical and system requirements. Deliverables Complete source code Database setup instructions (Scripts or restorable backup) Application installation instructions (Installer or installation procedure) Any necessary documentation Technical Requirements Server Platform – Windows XP / Windows Server 2003 / SBS Client Platform – Windows XP Web Browser (If applicable) – IE 8 Database – At developer’s discretion (Must be a relational SQL database.) Language – At developer’s discretion All data must be normalized. (+) All data must maintain referential integrity. (++) All data must be indexed for optimal performance. System must handle concurrency. System Requirements Customer Maintenance Customer records must have unique ID. Customer data will include Name, Address, Phone, etc. User must be able to perform all CRUD (Create, Read, Update, and Delete) operations on the Customer table. User must be able to enter a specific Customer ID to edit. User must be able to pull up a sortable/queryable search grid/utility to find a customer to edit. Validation must be performed prior to database commit. Customer record cannot be deleted if the customer has an order in the system. (++) Inventory Maintenance Part records must have unique ID. Part data will include Description, Price, UOM (Unit of Measure), etc. User must be able to perform all CRUD operations on the part table. User must be able to enter a specific Part ID to edit. User must be able to pull up a sortable/queryable search grid/utility to find a part to edit. Validation must be performed prior to database commit. Part record cannot be deleted if the part has been used in an order. (++) Order Entry Order records must have a unique auto-incrementing key (Order Number). Order data must be split into a header/detail structure. (+) Order can contain an infinite number of detail records. Order header data will include Order Number, Customer ID (++), Order Date, Order Status (Open/Closed), etc. Order detail data will include Part Number (++), Quantity, Price, etc. User must be able to perform all CRUD operations on the order tables. User must be able to enter a specific Order Number to edit. User must be able to pull up a sortable/queryable search grid/utility to find an order to edit. User must be able to print an order form from within the order entry form. Validation must be performed prior to database commit. Reports Customer Listing – All Customers in the system. Inventory Listing – All parts in the system. Open Order Listing – All open orders in system. Customer Order Listing – All orders for specific customer. All reports must include sorts and filter functions where applicable. Ex. Customer Listing by range of Customer IDs. Open Order Listing by date range.

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How to compare a memory bits in C++?

- by Trunet

Hi, I need help with a memory bit comparison function. I bought a LED Matrix here with 4 x HT1632C chips and I'm using it on my arduino mega2560. There're no code available for this chipset(it's not the same as HT1632) and I'm writing on my own. I have a plot function that get x,y coordinates and a color and that pixel turn on. Only this is working perfectly. But I need more performance on my display so I tried to make a shadowRam variable that is a "copy" of my device memory. Before I plot anything on display it checks on shadowRam to see if it's really necessary to change that pixel. When I enabled this(getShadowRam) on plot function my display has some, just SOME(like 3 or 4 on entire display) ghost pixels(pixels that is not supposed to be turned on). If I just comment the prev_color if's on my plot function it works perfectly. Also, I'm cleaning my shadowRam array setting all matrix to zero. variables: #define BLACK 0 #define GREEN 1 #define RED 2 #define ORANGE 3 #define CHIP_MAX 8 byte shadowRam[63][CHIP_MAX-1] = {0}; getShadowRam function: byte HT1632C::getShadowRam(byte x, byte y) { byte addr, bitval, nChip; if (x>=32) { nChip = 3 + x/16 + (y>7?2:0); } else { nChip = 1 + x/16 + (y>7?2:0); } bitval = 8>>(y&3); x = x % 16; y = y % 8; addr = (x<<1) + (y>>2); if ((shadowRam[addr][nChip-1] & bitval) && (shadowRam[addr+32][nChip-1] & bitval)) { return ORANGE; } else if (shadowRam[addr][nChip-1] & bitval) { return GREEN; } else if (shadowRam[addr+32][nChip-1] & bitval) { return RED; } else { return BLACK; } } plot function: void HT1632C::plot (int x, int y, int color) { if (x<0 || x>X_MAX || y<0 || y>Y_MAX) return; if (color != BLACK && color != GREEN && color != RED && color != ORANGE) return; char addr, bitval; byte nChip; byte prev_color = HT1632C::getShadowRam(x,y); bitval = 8>>(y&3); if (x>=32) { nChip = 3 + x/16 + (y>7?2:0); } else { nChip = 1 + x/16 + (y>7?2:0); } x = x % 16; y = y % 8; addr = (x<<1) + (y>>2); switch(color) { case BLACK: if (prev_color != BLACK) { // compare with memory to only set if pixel is other color // clear the bit in both planes; shadowRam[addr][nChip-1] &= ~bitval; HT1632C::sendData(nChip, addr, shadowRam[addr][nChip-1]); shadowRam[addr+32][nChip-1] &= ~bitval; HT1632C::sendData(nChip, addr+32, shadowRam[addr+32][nChip-1]); } break; case GREEN: if (prev_color != GREEN) { // compare with memory to only set if pixel is other color // set the bit in the green plane and clear the bit in the red plane; shadowRam[addr][nChip-1] |= bitval; HT1632C::sendData(nChip, addr, shadowRam[addr][nChip-1]); shadowRam[addr+32][nChip-1] &= ~bitval; HT1632C::sendData(nChip, addr+32, shadowRam[addr+32][nChip-1]); } break; case RED: if (prev_color != RED) { // compare with memory to only set if pixel is other color // clear the bit in green plane and set the bit in the red plane; shadowRam[addr][nChip-1] &= ~bitval; HT1632C::sendData(nChip, addr, shadowRam[addr][nChip-1]); shadowRam[addr+32][nChip-1] |= bitval; HT1632C::sendData(nChip, addr+32, shadowRam[addr+32][nChip-1]); } break; case ORANGE: if (prev_color != ORANGE) { // compare with memory to only set if pixel is other color // set the bit in both the green and red planes; shadowRam[addr][nChip-1] |= bitval; HT1632C::sendData(nChip, addr, shadowRam[addr][nChip-1]); shadowRam[addr+32][nChip-1] |= bitval; HT1632C::sendData(nChip, addr+32, shadowRam[addr+32][nChip-1]); } break; } } If helps: The datasheet of board I'm using. On page 7 has the memory mapping I'm using. Also, I have a video of display working.

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JSF : How to refresh required field in ajax request

- by Tama

Ok, here you are the core problem. The page. I have two required "input text". A command button that changes the bean value and reRenderes the "job" object. <a4j:form id="pervForm"> SURNAME:<h:inputText id="surname" label="Surname" value="#{prevManager.surname}" required="true" /> <br/> JOB:<h:inputText value="#{prevManager.job}" id="job" maxlength="10" size="10" label="#{msg.common_label_job}" required="true" /> <br/> <a4j:commandButton value="Set job to Programmer" ajaxSingle="true" reRender="job"> <a4j:actionparam name="jVal" value="Programmer" assignTo="#{prevManager.job}"/> </a4j:commandButton> <h:commandButton id="save" value="save" action="save" class="HATSBUTTON"/> </a4j:form> Here the simple manager: public class PrevManager { private String surname; private String job; public String getSurname() { return surname; } public void setSurname(String surname) { this.surname = surname; } public String getJob() { return job; } public void setJob(String job) { this.job = job; } public String save() { //do something } } Let's do this: Write something on the Job input text (such as "teacher"). Leave empty the surname. Save. Validation error appears (surname is mandatory). Press "Set job to Programmer": nothing happens. Checking the bean value, I discovered that it is correctly updated, indeed the component on the page is not updated! Well, according to the JBoss Docs I found: Ajax region is a key ajax component. It limits the part of the component tree to be processed on the server side when ajax request comes. Processing means invocation during Decode, Validation and Model Update phase. Most common reasons to use a region are: -avoiding the aborting of the JSF lifecycle processing during the validation of other form input unnecessary for given ajax request; -defining the different strategies when events will be delivered (immediate="true/false") -showing an individual indicator of an ajax status -increasing the performance of the rendering processing (selfRendered="true/false", renderRegionOnly="true/false") The following two examples show the situation when a validation error does not allow to process an ajax input. Type the name. The outputText component should reappear after you. However, in the first case, this activity will be aborted because of the other field with required="true". You will see only the error message while the "Job" field is empty. Here you are the example: <ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:a4j="http://richfaces.org/a4j" xmlns:rich="http://richfaces.org/rich"> <style> .outergridvalidationcolumn { padding: 0px 30px 10px 0px; } </style> <a4j:outputPanel ajaxRendered="true"> <h:messages style="color:red" /> </a4j:outputPanel> <h:panelGrid columns="2" columnClasses="outergridvalidationcolumn"> <h:form id="form1"> <h:panelGrid columns="2"> <h:outputText value="Name" /> <h:inputText value="#{userBean.name}"> <a4j:support event="onkeyup" reRender="outname" /> </h:inputText> <h:outputText value="Job" /> <h:inputText required="true" id="job2" value="#{userBean.job}" /> </h:panelGrid> </h:form> <h:form id="form2"> <h:panelGrid columns="2"> <h:outputText value="Name" /> <a4j:region> <h:inputText value="#{userBean.name}"> <a4j:support event="onkeyup" reRender="outname" /> </h:inputText> </a4j:region> <h:outputText value="Job" /> <h:inputText required="true" id="job1" value="#{userBean.job}" /> </h:panelGrid> </h:form> </h:panelGrid> <h:outputText id="outname" style="font-weight:bold" value="Typed Name: #{userBean.name}" /> <br /> </ui:composition> Form1: the behaviour is incorrect. I need to fill the job and then the name. Form2: the behaviour is correct. I do not need to fill the job to see the correct value. Unfortunately using Ajax region does not help (indeed I used it in a bad way ...) because my fields are both REQUIRED. That's the main different. Any idea? Many thanks.

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Database file is inexplicably locked during SQLite commit

- by sweeney

Hello, I'm performing a large number of INSERTS to a SQLite database. I'm using just one thread. I batch the writes to improve performance and have a bit of security in case of a crash. Basically I cache up a bunch of data in memory and then when I deem appropriate, I loop over all of that data and perform the INSERTS. The code for this is shown below: public void Commit() { using (SQLiteConnection conn = new SQLiteConnection(this.connString)) { conn.Open(); using (SQLiteTransaction trans = conn.BeginTransaction()) { using (SQLiteCommand command = conn.CreateCommand()) { command.CommandText = "INSERT OR IGNORE INTO [MY_TABLE] (col1, col2) VALUES (?,?)"; command.Parameters.Add(this.col1Param); command.Parameters.Add(this.col2Param); foreach (Data o in this.dataTemp) { this.col1Param.Value = o.Col1Prop; this. col2Param.Value = o.Col2Prop; command.ExecuteNonQuery(); } } this.TryHandleCommit(trans); } conn.Close(); } } I now employ the following gimmick to get the thing to eventually work: private void TryHandleCommit(SQLiteTransaction trans) { try { trans.Commit(); } catch (Exception e) { Console.WriteLine("Trying again..."); this.TryHandleCommit(trans); } } I create my DB like so: public DataBase(String path) { //build connection string SQLiteConnectionStringBuilder connString = new SQLiteConnectionStringBuilder(); connString.DataSource = path; connString.Version = 3; connString.DefaultTimeout = 5; connString.JournalMode = SQLiteJournalModeEnum.Persist; connString.UseUTF16Encoding = true; using (connection = new SQLiteConnection(connString.ToString())) { //check for existence of db FileInfo f = new FileInfo(path); if (!f.Exists) //build new blank db { SQLiteConnection.CreateFile(path); connection.Open(); using (SQLiteTransaction trans = connection.BeginTransaction()) { using (SQLiteCommand command = connection.CreateCommand()) { command.CommandText = DataBase.CREATE_MATCHES; command.ExecuteNonQuery(); command.CommandText = DataBase.CREATE_STRING_DATA; command.ExecuteNonQuery(); //TODO add logging } trans.Commit(); } connection.Close(); } } } I then export the connection string and use it to obtain new connections in different parts of the program. At seemingly random intervals, though at far too great a rate to ignore or otherwise workaround this problem, I get unhandled SQLiteException: Database file is locked. This occurs when I attempt to commit the transaction. No errors seem to occur prior to then. This does not always happen. Sometimes the whole thing runs without a hitch. No reads are being performed on these files before the commits finish. I have the very latest SQLite binary. I'm compiling for .NET 2.0. I'm using VS 2008. The db is a local file. All of this activity is encapsulated within one thread / process. Virus protection is off (though I think that was only relevant if you were connecting over a network?). As per Scotsman's post I have implemented the following changes: Journal Mode set to Persist DB files stored in C:\Docs + Settings\ApplicationData via System.Windows.Forms.Application.AppData windows call No inner exception Witnessed on two distinct machines (albeit very similar hardware and software) Have been running Process Monitor - no extraneous processes are attaching themselves to the DB files - the problem is definitely in my code... Does anyone have any idea whats going on here? I know I just dropped a whole mess of code, but I've been trying to figure this out for way too long. My thanks to anyone who makes it to the end of this question! brian UPDATES: Thanks for the suggestions so far! I've implemented many of the suggested changes. I feel that we are getting closer to the answer...however... The code above technically works however it is non-deterministic! It is not guaranteed to do anything aside from spin in neutral forever. In practice it seems to work somewhere between the 1st and 10th iteration. If i batch my commits at a reasonable interval damage will be mitigated but I really do not want to leave things in this state... More suggestions welcome!

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Jquery mobile page structure

- by Die 20

I built a jquery mobile site a while back and I have recently been expanding on it and noticing performance issues. I believe it is because I constructed the site using a multi-page set up where a single php file houses the following pages: **ALL_PAGES.PHP** <html> <head> /* external css and js files */ </head> <body> <div date-role="page" id="main"> <div class="page_link"> page 1 </div> <div class="page_link"> page 2 </div> <div class="page_link"> page 3 </div> </div> <div date-role="page" id="page 1"> <div class="page_link"> main </div> <div class="page_link"> page 2 </div> <div class="page_link"> page 3 </div> </div> <div date-role="page" id="page 2"> <div class="page_link"> main </div> <div class="page_link"> page 1 </div> <div class="page_link"> page 3 </div> </div> <div date-role="page" id="page 3"> <div class="page_link"> main </div> <div class="page_link"> page 1 </div> <div class="page_link"> page 2 </div> </div> </body> </html> **end ALL_PAGES.PHP ** I want to break away from this multi-page setup on one php file, and move to a setup where each page is a separate php file. To accomplish this I took the html from each page and moved it to its own php page. Then I added href links in replace of the mobile.change() functions I used for the "page_link" classes. **MAIN.PHP** <html> <head> external css and js files </head> <body> <div date-role="page" id="page 1"> <a href="/main.php"> main </a> <a href="/page_2.php"> page 2 </a> <a href="/page_3.php"> page 3 </a> </div> </body> </html> **end MAIN.PHP** **PAGE_1.PHP** <div date-role="page" id="page 1"> <a href="/main.php"> main </a> <a href="/page_2.php"> page 2 </a> <a href="/page_3.php"> page 3 </a> </div> **end PAGE_1.PHP** **PAGE_2.PHP** <div date-role="page" id="page 2"> <a href="/main.php"> main </a> <a href="/page_1.php"> page 1 </a> <a href="/page_3.php"> page 3 </a> </div> **end PAGE_2.PHP** **PAGE_3.PHP** <div date-role="page" id="page 3"> <a href="/main.php"> main </a> <a href="/page_1.php"> page 1 </a> <a href="/page_2.php"> page 2 </a> </div> **end PAGE_3.PHP** The site works fine except when the user hits the refresh button in the browser. When that happens each page loses access to any external css and js files located on the main page. I am fairly new to JQM so any advice would be helpful.

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Find the set of largest contiguous rectangles to cover multiple areas

- by joelpt

I'm working on a tool called Quickfort for the game Dwarf Fortress. Quickfort turns spreadsheets in csv/xls format into a series of commands for Dwarf Fortress to carry out in order to plot a "blueprint" within the game. I am currently trying to optimally solve an area-plotting problem for the 2.0 release of this tool. Consider the following "blueprint" which defines plotting commands for a 2-dimensional grid. Each cell in the grid should either be dug out ("d"), channeled ("c"), or left unplotted ("."). Any number of distinct plotting commands might be present in actual usage. . d . d c c d d d d c c . d d d . c d d d d d c . d . d d c To minimize the number of instructions that need to be sent to Dwarf Fortress, I would like to find the set of largest contiguous rectangles that can be formed to completely cover, or "plot", all of the plottable cells. To be valid, all of a given rectangle's cells must contain the same command. This is a faster approach than Quickfort 1.0 took: plotting every cell individually as a 1x1 rectangle. This video shows the performance difference between the two versions. For the above blueprint, the solution looks like this: . 9 . 0 3 2 8 1 1 1 3 2 . 1 1 1 . 2 7 1 1 1 4 2 . 6 . 5 4 2 Each same-numbered rectangle above denotes a contiguous rectangle. The largest rectangles take precedence over smaller rectangles that could also be formed in their areas. The order of the numbering/rectangles is unimportant. My current approach is iterative. In each iteration, I build a list of the largest rectangles that could be formed from each of the grid's plottable cells by extending in all 4 directions from the cell. After sorting the list largest first, I begin with the largest rectangle found, mark its underlying cells as "plotted", and record the rectangle in a list. Before plotting each rectangle, its underlying cells are checked to ensure they are not yet plotted (overlapping a previous plot). We then start again, finding the largest remaining rectangles that can be formed and plotting them until all cells have been plotted as part of some rectangle. I consider this approach slightly more optimized than a dumb brute-force search, but I am wasting a lot of cycles (re)calculating cells' largest rectangles and checking underlying cells' states. Currently, this rectangle-discovery routine takes the lion's share of the total runtime of the tool, especially for large blueprints. I have sacrificed some accuracy for the sake of speed by only considering rectangles from cells which appear to form a rectangle's corner (determined using some neighboring-cell heuristics which aren't always correct). As a result of this 'optimization', my current code doesn't actually generate the above solution correctly, but it's close enough. More broadly, I consider the goal of largest-rectangles-first to be a "good enough" approach for this application. However I observe that if the goal is instead to find the minimum set (fewest number) of rectangles to completely cover multiple areas, the solution would look like this instead: . 3 . 5 6 8 1 3 4 5 6 8 . 3 4 5 . 8 2 3 4 5 7 8 . 3 . 5 7 8 This second goal actually represents a more optimal solution to the problem, as fewer rectangles usually means fewer commands sent to Dwarf Fortress. However, this approach strikes me as closer to NP-Hard, based on my limited math knowledge. Watch the video if you'd like to better understand the overall strategy; I have not addressed other aspects of Quickfort's process, such as finding the shortest cursor-path that plots all rectangles. Possibly there is a solution to this problem that coherently combines these multiple strategies. Help of any form would be appreciated.

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Which workaround to use for the following SQL deadlock?

- by Marko

I found a SQL deadlock scenario in my application during concurrency. I belive that the two statements that cause the deadlock are (note - I'm using LINQ2SQL and DataContext.ExecuteCommand(), that's where this.studioId.ToString() comes into play): exec sp_executesql N'INSERT INTO HQ.dbo.SynchronizingRows ([StudioId], [UpdatedRowId]) SELECT @p0, [t0].[Id] FROM [dbo].[UpdatedRows] AS [t0] WHERE NOT (EXISTS( SELECT NULL AS [EMPTY] FROM [dbo].[ReceivedUpdatedRows] AS [t1] WHERE ([t1].[StudioId] = @p0) AND ([t1].[UpdatedRowId] = [t0].[Id]) ))',N'@p0 uniqueidentifier',@p0='" + this.studioId.ToString() + "'; and exec sp_executesql N'INSERT INTO HQ.dbo.ReceivedUpdatedRows ([UpdatedRowId], [StudioId], [ReceiveDateTime]) SELECT [t0].[UpdatedRowId], @p0, GETDATE() FROM [dbo].[SynchronizingRows] AS [t0] WHERE ([t0].[StudioId] = @p0)',N'@p0 uniqueidentifier',@p0='" + this.studioId.ToString() + "'; The basic logic of my (client-server) application is this: Every time someone inserts or updates a row on the server side, I also insert a row into the table UpdatedRows, specifying the RowId of the modified row. When a client tries to synchronize data, it first copies all of the rows in the UpdatedRows table, that don't contain a reference row for the specific client in the table ReceivedUpdatedRows, to the table SynchronizingRows (the first statement taking part in the deadlock). Afterwards, during the synchronization I look for modified rows via lookup of the SynchronizingRows table. This step is required, otherwise if someone inserts new rows or modifies rows on the server side during synchronization I will miss them and won't get them during the next synchronization (explanation scenario to long to write here...). Once synchronization is complete, I insert rows to the ReceivedUpdatedRows table specifying that this client has received the UpdatedRows contained in the SynchronizingRows table (the second statement taking part in the deadlock). Finally I delete all rows from the SynchronizingRows table that belong to the current client. The way I see it, the deadlock is occuring on tables SynchronizingRows (abbreviation SR) and ReceivedUpdatedRows (abbreviation RUR) during steps 2 and 3 (one client is in step 2 and is inserting into SR and selecting from RUR; while another client is in step 3 inserting into RUR and selecting from SR). I googled a bit about SQL deadlocks and came to a conclusion that I have three options. Inorder to make a decision I need more input about each option/workaround: Workaround 1: The first advice given on the web about SQL deadlocks - restructure tables/queries so that deadlocks don't happen in the first place. Only problem with this is that with my IQ I don't see a way to do the synchronization logic any differently. If someone wishes to dwelve deeper into my current synchronization logic, how and why it is set up the way it is, I'll post a link for the explanation. Perhaps, with the help of someone smarter than me, it's possible to create a logic that is deadlock free. Workaround 2: The second most common advice seems to be the use of WITH(NOLOCK) hint. The problem with this is that NOLOCK might miss or duplicate some rows. Duplication is not a problem, but missing rows is catastrophic! Another option is the WITH(READPAST) hint. On the face of it, this seems to be a perfect solution. I really don't care about rows that other clients are inserting/modifying, because each row belongs only to a specific client, so I may very well skip locked rows. But the MSDN documentaion makes me a bit worried - "When READPAST is specified, both row-level and page-level locks are skipped". As I said, row-level locks would not be a problem, but page-level locks may very well be, since a page might contain rows that belong to multiple clients (including the current one). While there are lots of blog posts specifically mentioning that NOLOCK might miss rows, there seems to be none about READPAST (never) missing rows. This makes me skeptical and nervous to implement it, since there is no easy way to test it (implementing would be a piece of cake, just pop WITH(READPAST) into both statements SELECT clause and job done). Can someone confirm whether the READPAST hint can miss rows? Workaround 3: The final option is to use ALLOW_SNAPSHOT_ISOLATION and READ_COMMITED_SNAPSHOT. This would seem to be the only option to work 100% - at least I can't find any information that would contradict with it. But it is a little bit trickier to setup (I don't care much about the performance hit), because I'm using LINQ. Off the top of my head I probably need to manually open a SQL connection and pass it to the LINQ2SQL DataContext, etc... I haven't looked into the specifics very deeply. Mostly I would prefer option 2 if somone could only reassure me that READPAST will never miss rows concerning the current client (as I said before, each client has and only ever deals with it's own set of rows). Otherwise I'll likely have to implement option 3, since option 1 is probably impossible... I'll post the table definitions for the three tables as well, just in case: CREATE TABLE [dbo].[UpdatedRows]( [Id] [uniqueidentifier] NOT NULL ROWGUIDCOL DEFAULT NEWSEQUENTIALID() PRIMARY KEY CLUSTERED, [RowId] [uniqueidentifier] NOT NULL, [UpdateDateTime] [datetime] NOT NULL, ) ON [PRIMARY] GO CREATE NONCLUSTERED INDEX IX_RowId ON dbo.UpdatedRows ([RowId] ASC) WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE TABLE [dbo].[ReceivedUpdatedRows]( [Id] [uniqueidentifier] NOT NULL ROWGUIDCOL DEFAULT NEWSEQUENTIALID() PRIMARY KEY NONCLUSTERED, [UpdatedRowId] [uniqueidentifier] NOT NULL REFERENCES [dbo].[UpdatedRows] ([Id]), [StudioId] [uniqueidentifier] NOT NULL REFERENCES, [ReceiveDateTime] [datetime] NOT NULL, ) ON [PRIMARY] GO CREATE CLUSTERED INDEX IX_Studios ON dbo.ReceivedUpdatedRows ([StudioId] ASC) WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE TABLE [dbo].[SynchronizingRows]( [StudioId] [uniqueidentifier] NOT NULL [UpdatedRowId] [uniqueidentifier] NOT NULL REFERENCES [dbo].[UpdatedRows] ([Id]) PRIMARY KEY CLUSTERED ([StudioId], [UpdatedRowId]) ) ON [PRIMARY] GO PS! Studio = Client. PS2! I just noticed that the index definitions have ALLOW_PAGE_LOCK=ON. If I would turn it off, would that make any difference to READPAST? Are there any negative downsides for turning it off?

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Writing an optimised and efficient search engine with mySQL and ColdFusion

- by Mel

I have a search page with the following scenarios listed below. I was told there was a better way to do it, but not how, and that I am using too many if statements, and that it's prone to causing an error through url manipulation: Search.cfm will processes a search made from a search bar present on all pages, with one search input (titleName). If search.cfm is accessed manually (through URL not through using the simple search bar on all pages) it displays an advanced search form with three inputs (titleName, genreID, platformID) or it evaluates searchResponse variable and decides what to do. If simple search query is blank, has no results, or less than 3 characters it displays an error If advanced search query is blank, has no results, or less than 3 characters it displays an error If any successful search returns results, they come back normally. The top-of-page logic is as follows:  <cfparam name="variables.searchResponse" default="">  <cfif IsDefined("Form.simpleSearch") AND Len(Trim(Form.titleName)) LTE 2> <cfset variables.searchResponse = "invalidString"> <cfelseif IsDefined("Form.simpleSearch") AND Len(Trim(Form.titleName)) GTE 3>  <cfinvoke component="myComponent" method="simpleSearch" searchString="#Form.titleName#" returnvariable="simpleSearchResult"> <cfset variables.searchResponse = "simpleSearchResult"> </cfif>  <cfif IsDefined("variables.simpleSearchResult") AND simpleSearchResult.RecordCount IS 0> <cfset variables.searchResponse = "noResult"> </cfif>  <cfif IsDefined("Form.AdvancedSearch") AND Len(Trim(Form.titleName)) LTE 2> <cfset variables.searchResponse = "invalidString"> <cfelseif IsDefined("Form.advancedSearch") AND Len(Trim(Form.titleName)) GTE 2>  <cfinvoke component="myComponent" method="advancedSearch" returnvariable="advancedSearchResult" titleName="#Form.titleName#" genreID="#Form.genreID#" platformID="#Form.platformID#"> <cfset variables.searchResponse = "advancedSearchResult"> </cfif>  <cfif IsDefined("variables.advancedSearchResult") AND advancedSearchResult.RecordCount IS 0> <cfset variables.searchResponse = "noResult"> </cfif> I'm using the searchResponse variable to decide what the the page displays, based on the following scenarios:  <form name="simpleSearch" action="search.cfm" method="post"> <input type="hidden" name="simpleSearch" /> <input type="text" name="titleName" /> <input type="button" value="Search" onclick="form.submit()" /> </form>  <cfif searchResponse IS ""> <h1>Advanced Search</h1>  <form name="advancedSearch" action="search.cfm" method="post"> <input type="hidden" name="advancedSearch" /> <input type="text" name="titleName" /> <input type="text" name="genreID" /> <input type="text" name="platformID" /> <input type="button" value="Search" onclick="form.submit()" /> </form> </cfif>  <cfif searchResponse IS "invalidString"> <cfoutput> <h1>INVALID SEARCH</h1> </cfoutput> </cfif>  <cfif searchResponse IS "noResult"> <cfoutput> <h1>NO RESULT FOUND</h1> </cfoutput> </cfif>  <cfif searchResponse IS "simpleSearchResult"> <cfoutput> <h1>Search Results</h1> </cfoutput> <cfoutput query="simpleSearchResult">  </cfoutput> </cfif>  <cfif searchResponse IS "advancedSearchResult"> <cfoutput> <h1>Search Results</h1> <p>Your search for "#Form.titleName#" returned #advancedSearchResult.RecordCount# result(s).</p> </cfoutput> <cfoutput query="advancedSearchResult">  </cfoutput> </cfif> Is my logic a) not efficient because my if statements/is there a better way to do this? And b) Can you see any scenarios where my code can break? I've tested it but I have not been able to find any issues with it. And I have no way of measuring performance. Any thoughts and ideas would be greatly appreciated. Many thanks

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How to stop rendering invisible faces

- by TheMorfeus

I am making a voxel-based game, and for needs of it, i am creating a block rendering engine. Point is, that i need to generate lots of cubes. Every time i render more than 16x16x16 chunk of theese blocks, my FPS is dropped down hardly, because it renders all 6 faces of all of theese cubes. THat's 24 576 quads, and i dont want that. So, my question is, How to stop rendering vertices(or quads) that are not visible, and therefore increase performance of my game? Here is class for rendering of a block: public void renderBlock(int posx, int posy, int posz) { try{ //t.bind(); glEnable(GL_CULL_FACE); glCullFace(GL_BACK);// or even GL_FRONT_AND_BACK */); glPushMatrix(); GL11.glTranslatef((2*posx+0.5f),(2*posy+0.5f),(2*posz+0.5f)); // Move Right 1.5 Units And Into The Screen 6.0 GL11.glRotatef(rquad,1.0f,1.0f,1.0f); glBegin(GL_QUADS); // Draw A Quad GL11.glColor3f(0.5f, 0.4f, 0.4f); // Set The Color To Green GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f, 1f,-1f); // Top Right Of The Quad (Top) GL11.glTexCoord2f(1,0); GL11.glVertex3f(-1f, 1f,-1f); // Top Left Of The Quad (Top) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f, 1f, 1f); // Bottom Left Of The Quad (Top) GL11.glTexCoord2f(0,1); GL11.glVertex3f( 1f, 1f, 1f); // Bottom Right Of The Quad (Top) //GL11.glColor3f(1.2f,0.5f,0.9f); // Set The Color To Orange GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f,-1f, 1f); // Top Right Of The Quad (Bottom) GL11.glTexCoord2f(0,1); GL11.glVertex3f(-1f,-1f, 1f); // Top Left Of The Quad (Bottom) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f,-1f,-1f); // Bottom Left Of The Quad (Bottom) GL11.glTexCoord2f(1,0); GL11.glVertex3f( 1f,-1f,-1f); // Bottom Right Of The Quad (Bottom) //GL11.glColor3f(1.0f,0.0f,0.0f); // Set The Color To Red GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f, 1f, 1f); // Top Right Of The Quad (Front) GL11.glTexCoord2f(1,0); GL11.glVertex3f(-1f, 1f, 1f); // Top Left Of The Quad (Front) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f,-1f, 1f); // Bottom Left Of The Quad (Front) GL11.glTexCoord2f(0,1); GL11.glVertex3f( 1f,-1f, 1f); // Bottom Right Of The Quad (Front) //GL11.glColor3f(1f,0.5f,0.0f); // Set The Color To Yellow GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f,-1f,-1f); // Bottom Left Of The Quad (Back) GL11.glTexCoord2f(1,0); GL11.glVertex3f(-1f,-1f,-1f); // Bottom Right Of The Quad (Back) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f, 1f,-1f); // Top Right Of The Quad (Back) GL11.glTexCoord2f(0,1); GL11.glVertex3f( 1f, 1f,-1f); // Top Left Of The Quad (Back) //GL11.glColor3f(0.0f,0.0f,0.3f); // Set The Color To Blue GL11.glTexCoord2f(0,1); GL11.glVertex3f(-1f, 1f, 1f); // Top Right Of The Quad (Left) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f, 1f,-1f); // Top Left Of The Quad (Left) GL11.glTexCoord2f(1,0); GL11.glVertex3f(-1f,-1f,-1f); // Bottom Left Of The Quad (Left) GL11.glTexCoord2f(0,0); GL11.glVertex3f(-1f,-1f, 1f); // Bottom Right Of The Quad (Left) //GL11.glColor3f(0.5f,0.0f,0.5f); // Set The Color To Violet GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f, 1f,-1f); // Top Right Of The Quad (Right) GL11.glTexCoord2f(1,0); GL11.glVertex3f( 1f, 1f, 1f); // Top Left Of The Quad (Right) GL11.glTexCoord2f(1,1); GL11.glVertex3f( 1f,-1f, 1f); // Bottom Left Of The Quad (Right) GL11.glTexCoord2f(0,1); GL11.glVertex3f( 1f,-1f,-1f); // Bottom Right Of The Quad (Right) //rquad+=0.0001f; glEnd(); glPopMatrix(); }catch(NullPointerException t){t.printStackTrace(); System.out.println("rendering block failed");} } Here is code that renders them: private void render() { GL11.glClear(GL11.GL_COLOR_BUFFER_BIT|GL11.GL_DEPTH_BUFFER_BIT); for(int y=0; y<32; y++){ for(int x=0; x<16; x++){ for(int z=0; z<16; z++) { b.renderBlock(x, y, z); } } } }

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Integrating JavaScript Unit Tests with Visual Studio

- by Stephen Walther

Modern ASP.NET web applications take full advantage of client-side JavaScript to provide better interactivity and responsiveness. If you are building an ASP.NET application in the right way, you quickly end up with lots and lots of JavaScript code. When writing server code, you should be writing unit tests. One big advantage of unit tests is that they provide you with a safety net that enable you to safely modify your existing code – for example, fix bugs, add new features, and make performance enhancements -- without breaking your existing code. Every time you modify your code, you can execute your unit tests to verify that you have not broken anything. For the same reason that you should write unit tests for your server code, you should write unit tests for your client code. JavaScript is just as susceptible to bugs as C#. There is no shortage of unit testing frameworks for JavaScript. Each of the major JavaScript libraries has its own unit testing framework. For example, jQuery has QUnit, Prototype has UnitTestJS, YUI has YUI Test, and Dojo has Dojo Objective Harness (DOH). The challenge is integrating a JavaScript unit testing framework with Visual Studio. Visual Studio and Visual Studio ALM provide fantastic support for server-side unit tests. You can easily view the results of running your unit tests in the Visual Studio Test Results window. You can set up a check-in policy which requires that all unit tests pass before your source code can be committed to the source code repository. In addition, you can set up Team Build to execute your unit tests automatically. Unfortunately, Visual Studio does not provide “out-of-the-box” support for JavaScript unit tests. MS Test, the unit testing framework included in Visual Studio, does not support JavaScript unit tests. As soon as you leave the server world, you are left on your own. The goal of this blog entry is to describe one approach to integrating JavaScript unit tests with MS Test so that you can execute your JavaScript unit tests side-by-side with your C# unit tests. The goal is to enable you to execute JavaScript unit tests in exactly the same way as server-side unit tests. You can download the source code described by this project by scrolling to the end of this blog entry. Rejected Approach: Browser Launchers One popular approach to executing JavaScript unit tests is to use a browser as a test-driver. When you use a browser as a test-driver, you open up a browser window to execute and view the results of executing your JavaScript unit tests. For example, QUnit – the unit testing framework for jQuery – takes this approach. The following HTML page illustrates how you can use QUnit to create a unit test for a function named addNumbers(). <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>Using QUnit</title> <link rel="stylesheet" href="http://github.com/jquery/qunit/raw/master/qunit/qunit.css" type="text/css" /> </head> <body> <h1 id="qunit-header">QUnit example</h1> <h2 id="qunit-banner"></h2> <div id="qunit-testrunner-toolbar"></div> <h2 id="qunit-userAgent"></h2> <ol id="qunit-tests"></ol> <div id="qunit-fixture">test markup, will be hidden</div> <script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script> <script type="text/javascript" src="http://github.com/jquery/qunit/raw/master/qunit/qunit.js"></script> <script type="text/javascript"> // The function to test function addNumbers(a, b) { return a+b; } // The unit test test("Test of addNumbers", function () { equals(4, addNumbers(1,3), "1+3 should be 4"); }); </script> </body> </html> This test verifies that calling addNumbers(1,3) returns the expected value 4. When you open this page in a browser, you can see that this test does, in fact, pass. The idea is that you can quickly refresh this QUnit HTML JavaScript test driver page in your browser whenever you modify your JavaScript code. In other words, you can keep a browser window open and keep refreshing it over and over while you are developing your application. That way, you can know very quickly whenever you have broken your JavaScript code. While easy to setup, there are several big disadvantages to this approach to executing JavaScript unit tests: You must view your JavaScript unit test results in a different location than your server unit test results. The JavaScript unit test results appear in the browser and the server unit test results appear in the Visual Studio Test Results window. Because all of your unit test results don’t appear in a single location, you are more likely to introduce bugs into your code without noticing it. Because your unit tests are not integrated with Visual Studio – in particular, MS Test -- you cannot easily include your JavaScript unit tests when setting up check-in policies or when performing automated builds with Team Build. A more sophisticated approach to using a browser as a test-driver is to automate the web browser. Instead of launching the browser and loading the test code yourself, you use a framework to automate this process. There are several different testing frameworks that support this approach: · Selenium – Selenium is a very powerful framework for automating browser tests. You can create your tests by recording a Firefox session or by writing the test driver code in server code such as C#. You can learn more about Selenium at http://seleniumhq.org/. LTAF – The ASP.NET team uses the Lightweight Test Automation Framework to test JavaScript code in the ASP.NET framework. You can learn more about LTAF by visiting the project home at CodePlex: http://aspnet.codeplex.com/releases/view/35501 jsTestDriver – This framework uses Java to automate the browser. jsTestDriver creates a server which can be used to automate multiple browsers simultaneously. This project is located at http://code.google.com/p/js-test-driver/ TestSwam – This framework, created by John Resig, uses PHP to automate the browser. Like jsTestDriver, the framework creates a test server. You can open multiple browsers that are automated by the test server. Learn more about TestSwarm by visiting the following address: https://github.com/jeresig/testswarm/wiki Yeti – This is the framework introduced by Yahoo for automating browser tests. Yeti uses server-side JavaScript and depends on Node.js. Learn more about Yeti at http://www.yuiblog.com/blog/2010/08/25/introducing-yeti-the-yui-easy-testing-interface/ All of these frameworks are great for integration tests – however, they are not the best frameworks to use for unit tests. In one way or another, all of these frameworks depend on executing tests within the context of a “living and breathing” browser. If you create an ASP.NET Unit Test then Visual Studio will launch a web server before executing the unit test. Why is launching a web server so bad? It is not the worst thing in the world. However, it does introduce dependencies that prevent your code from being tested in isolation. One of the defining features of a unit test -- versus an integration test – is that a unit test tests code in isolation. Another problem with launching a web server when performing unit tests is that launching a web server can be slow. If you cannot execute your unit tests quickly, you are less likely to execute your unit tests each and every time you make a code change. You are much more likely to fall into the pit of failure. Launching a browser when performing a JavaScript unit test has all of the same disadvantages as launching a web server when performing an ASP.NET unit test. Instead of testing a unit of JavaScript code in isolation, you are testing JavaScript code within the context of a particular browser. Using the frameworks listed above for integration tests makes perfect sense. However, I want to consider a different approach for creating unit tests for JavaScript code. Using Server-Side JavaScript for JavaScript Unit Tests A completely different approach to executing JavaScript unit tests is to perform the tests outside of any browser. If you really want to test JavaScript then you should test JavaScript and leave the browser out of the testing process. There are several ways that you can execute JavaScript on the server outside the context of any browser: Rhino – Rhino is an implementation of JavaScript written in Java. The Rhino project is maintained by the Mozilla project. Learn more about Rhino at http://www.mozilla.org/rhino/ V8 – V8 is the open-source Google JavaScript engine written in C++. This is the JavaScript engine used by the Chrome web browser. You can download V8 and embed it in your project by visiting http://code.google.com/p/v8/ JScript – JScript is the JavaScript Script Engine used by Internet Explorer (up to but not including Internet Explorer 9), Windows Script Host, and Active Server Pages. Internet Explorer is still the most popular web browser. Therefore, I decided to focus on using the JScript Script Engine to execute JavaScript unit tests. Using the Microsoft Script Control There are two basic ways that you can pass JavaScript to the JScript Script Engine and execute the code: use the Microsoft Windows Script Interfaces or use the Microsoft Script Control. The difficult and proper way to execute JavaScript using the JScript Script Engine is to use the Microsoft Windows Script Interfaces. You can learn more about the Script Interfaces by visiting http://msdn.microsoft.com/en-us/library/t9d4xf28(VS.85).aspx The main disadvantage of using the Script Interfaces is that they are difficult to use from .NET. There is a great series of articles on using the Script Interfaces from C# located at http://www.drdobbs.com/184406028. I picked the easier alternative and used the Microsoft Script Control. The Microsoft Script Control is an ActiveX control that provides a higher level abstraction over the Window Script Interfaces. You can download the Microsoft Script Control from here: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=d7e31492-2595-49e6-8c02-1426fec693ac After you download the Microsoft Script Control, you need to add a reference to it to your project. Select the Visual Studio menu option Project, Add Reference to open the Add Reference dialog. Select the COM tab and add the Microsoft Script Control 1.0. Using the Script Control is easy. You call the Script Control AddCode() method to add JavaScript code to the Script Engine. Next, you call the Script Control Run() method to run a particular JavaScript function. The reference documentation for the Microsoft Script Control is located at the MSDN website: http://msdn.microsoft.com/en-us/library/aa227633%28v=vs.60%29.aspx Creating the JavaScript Code to Test To keep things simple, let’s imagine that you want to test the following JavaScript function named addNumbers() which simply adds two numbers together: MvcApplication1\Scripts\Math.js function addNumbers(a, b) { return 5; } Notice that the addNumbers() method always returns the value 5. Right-now, it will not pass a good unit test. Create this file and save it in your project with the name Math.js in your MVC project’s Scripts folder (Save the file in your actual MVC application and not your MVC test application). Creating the JavaScript Test Helper Class To make it easier to use the Microsoft Script Control in unit tests, we can create a helper class. This class contains two methods: LoadFile() – Loads a JavaScript file. Use this method to load the JavaScript file being tested or the JavaScript file containing the unit tests. ExecuteTest() – Executes the JavaScript code. Use this method to execute a JavaScript unit test. Here’s the code for the JavaScriptTestHelper class: JavaScriptTestHelper.cs using System; using System.IO; using Microsoft.VisualStudio.TestTools.UnitTesting; using MSScriptControl; namespace MvcApplication1.Tests { public class JavaScriptTestHelper : IDisposable { private ScriptControl _sc; private TestContext _context; /// <summary> /// You need to use this helper with Unit Tests and not /// Basic Unit Tests because you need a Test Context /// </summary> /// <param name="testContext">Unit Test Test Context</param> public JavaScriptTestHelper(TestContext testContext) { if (testContext == null) { throw new ArgumentNullException("TestContext"); } _context = testContext; _sc = new ScriptControl(); _sc.Language = "JScript"; _sc.AllowUI = false; } /// <summary> /// Load the contents of a JavaScript file into the /// Script Engine. /// </summary> /// <param name="path">Path to JavaScript file</param> public void LoadFile(string path) { var fileContents = File.ReadAllText(path); _sc.AddCode(fileContents); } /// <summary> /// Pass the path of the test that you want to execute. /// </summary> /// <param name="testMethodName">JavaScript function name</param> public void ExecuteTest(string testMethodName) { dynamic result = null; try { result = _sc.Run(testMethodName, new object[] { }); } catch { var error = ((IScriptControl)_sc).Error; if (error != null) { var description = error.Description; var line = error.Line; var column = error.Column; var text = error.Text; var source = error.Source; if (_context != null) { var details = String.Format("{0} \r\nLine: {1} Column: {2}", source, line, column); _context.WriteLine(details); } } throw new AssertFailedException(error.Description); } } public void Dispose() { _sc = null; } } } Notice that the JavaScriptTestHelper class requires a Test Context to be instantiated. For this reason, you can use the JavaScriptTestHelper only with a Visual Studio Unit Test and not a Basic Unit Test (These are two different types of Visual Studio project items). Add the JavaScriptTestHelper file to your MVC test application (for example, MvcApplication1.Tests). Creating the JavaScript Unit Test Next, we need to create the JavaScript unit test function that we will use to test the addNumbers() function. Create a folder in your MVC test project named JavaScriptTests and add the following JavaScript file to this folder: MvcApplication1.Tests\JavaScriptTests\MathTest.js /// <reference path="JavaScriptUnitTestFramework.js"/> function testAddNumbers() { // Act var result = addNumbers(1, 3); // Assert assert.areEqual(4, result, "addNumbers did not return right value!"); } The testAddNumbers() function takes advantage of another JavaScript library named JavaScriptUnitTestFramework.js. This library contains all of the code necessary to make assertions. Add the following JavaScriptnitTestFramework.js to the same folder as the MathTest.js file: MvcApplication1.Tests\JavaScriptTests\JavaScriptUnitTestFramework.js var assert = { areEqual: function (expected, actual, message) { if (expected !== actual) { throw new Error("Expected value " + expected + " is not equal to " + actual + ". " + message); } } }; There is only one type of assertion supported by this file: the areEqual() assertion. Most likely, you would want to add additional types of assertions to this file to make it easier to write your JavaScript unit tests. Deploying the JavaScript Test Files This step is non-intuitive. When you use Visual Studio to run unit tests, Visual Studio creates a new folder and executes a copy of the files in your project. After you run your unit tests, your Visual Studio Solution will contain a new folder named TestResults that includes a subfolder for each test run. You need to configure Visual Studio to deploy your JavaScript files to the test run folder or Visual Studio won’t be able to find your JavaScript files when you execute your unit tests. You will get an error that looks something like this when you attempt to execute your unit tests: You can configure Visual Studio to deploy your JavaScript files by adding a Test Settings file to your Visual Studio Solution. It is important to understand that you need to add this file to your Visual Studio Solution and not a particular Visual Studio project. Right-click your Solution in the Solution Explorer window and select the menu option Add, New Item. Select the Test Settings item and click the Add button. After you create a Test Settings file for your solution, you can indicate that you want a particular folder to be deployed whenever you perform a test run. Select the menu option Test, Edit Test Settings to edit your test configuration file. Select the Deployment tab and select your MVC test project’s JavaScriptTest folder to deploy. Click the Apply button and the Close button to save the changes and close the dialog. Creating the Visual Studio Unit Test The very last step is to create the Visual Studio unit test (the MS Test unit test). Add a new unit test to your MVC test project by selecting the menu option Add New Item and selecting the Unit Test project item (Do not select the Basic Unit Test project item): The difference between a Basic Unit Test and a Unit Test is that a Unit Test includes a Test Context. We need this Test Context to use the JavaScriptTestHelper class that we created earlier. Enter the following test method for the new unit test: [TestMethod] public void TestAddNumbers() { var jsHelper = new JavaScriptTestHelper(this.TestContext); // Load JavaScript files jsHelper.LoadFile("JavaScriptUnitTestFramework.js"); jsHelper.LoadFile(@"..\..\..\MvcApplication1\Scripts\Math.js"); jsHelper.LoadFile("MathTest.js"); // Execute JavaScript Test jsHelper.ExecuteTest("testAddNumbers"); } This code uses the JavaScriptTestHelper to load three files: JavaScripUnitTestFramework.js – Contains the assert functions. Math.js – Contains the addNumbers() function from your MVC application which is being tested. MathTest.js – Contains the JavaScript unit test function. Next, the test method calls the JavaScriptTestHelper ExecuteTest() method to execute the testAddNumbers() JavaScript function. Running the Visual Studio JavaScript Unit Test After you complete all of the steps described above, you can execute the JavaScript unit test just like any other unit test. You can use the keyboard combination CTRL-R, CTRL-A to run all of the tests in the current Visual Studio Solution. Alternatively, you can use the buttons in the Visual Studio toolbar to run the tests: (Unfortunately, the Run All Impacted Tests button won’t work correctly because Visual Studio won’t detect that your JavaScript code has changed. Therefore, you should use either the Run Tests in Current Context or Run All Tests in Solution options instead.) The results of running the JavaScript tests appear side-by-side with the results of running the server tests in the Test Results window. For example, if you Run All Tests in Solution then you will get the following results: Notice that the TestAddNumbers() JavaScript test has failed. That is good because our addNumbers() function is hard-coded to always return the value 5. If you double-click the failing JavaScript test, you can view additional details such as the JavaScript error message and the line number of the JavaScript code that failed: Summary The goal of this blog entry was to explain an approach to creating JavaScript unit tests that can be easily integrated with Visual Studio and Visual Studio ALM. I described how you can use the Microsoft Script Control to execute JavaScript on the server. By taking advantage of the Microsoft Script Control, we were able to execute our JavaScript unit tests side-by-side with all of our other unit tests and view the results in the standard Visual Studio Test Results window. You can download the code discussed in this blog entry from here: http://StephenWalther.com/downloads/Blog/JavaScriptUnitTesting/JavaScriptUnitTests.zip Before running this code, you need to first install the Microsoft Script Control which you can download from here: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=d7e31492-2595-49e6-8c02-1426fec693ac

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Integrating HTML into Silverlight Applications

- by dwahlin

Looking for a way to display HTML content within a Silverlight application? If you haven’t tried doing that before it can be challenging at first until you know a few tricks of the trade. Being able to display HTML is especially handy when you’re required to display RSS feeds (with embedded HTML), SQL Server Reporting Services reports, PDF files (not actually HTML – but the techniques discussed will work), or other HTML content. In this post I'll discuss three options for displaying HTML content in Silverlight applications and describe how my company is using these techniques in client applications. Displaying HTML Overlays If you need to display HTML over a Silverlight application (such as an RSS feed containing HTML data in it) you’ll need to set the Silverlight control’s windowless parameter to true. This can be done using the object tag as shown next: <object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%"> <param name="source" value="ClientBin/HTMLAndSilverlight.xap"/> <param name="onError" value="onSilverlightError" /> <param name="background" value="white" /> <param name="minRuntimeVersion" value="4.0.50401.0" /> <param name="autoUpgrade" value="true" /> <param name="windowless" value="true" /> <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50401.0" style="text-decoration:none"> <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/> </a> </object> By setting the control to “windowless” you can overlay HTML objects by using absolute positioning and other CSS techniques. Keep in mind that on Windows machines the windowless setting can result in a performance hit when complex animations or HD video are running since the plug-in content is displayed directly by the browser window. It goes without saying that you should only set windowless to true when you really need the functionality it offers. For example, if I want to display my blog’s RSS content on top of a Silverlight application I could set windowless to true and create a user control that grabbed the content and output it using a DataList control: <style type="text/css"> a {text-decoration:none;font-weight:bold;font-size:14pt;} </style> <div style="margin-top:10px; margin-left:10px;margin-right:5px;"> <asp:DataList ID="RSSDataList" runat="server" DataSourceID="RSSDataSource"> <ItemTemplate> <a href='<%# XPath("link") %>'><%# XPath("title") %></a> <br /> <%# XPath("description") %> <br /> </ItemTemplate> </asp:DataList> <asp:XmlDataSource ID="RSSDataSource" DataFile="http://weblogs.asp.net/dwahlin/rss.aspx" XPath="rss/channel/item" CacheDuration="60" runat="server" /> </div> The user control can then be placed in the page hosting the Silverlight control as shown below. This example adds a Close button, additional content to display in the overlay window and the HTML generated from the user control. <div id="RSSDiv"> <div style="background-color:#484848;border:1px solid black;height:35px;width:100%;"> <img alt="Close Button" align="right" src="Images/Close.png" onclick="HideOverlay();" style="cursor:pointer;" /> </div> <div style="overflow:auto;width:800px;height:565px;"> <div style="float:left;width:100px;height:103px;margin-left:10px;margin-top:5px;"> <img src="http://weblogs.asp.net/blogs/dwahlin/dan2008.jpg" style="border:1px solid Gray" /> </div> <div style="float:left;width:300px;height:103px;margin-top:5px;"> <a href="http://weblogs.asp.net/dwahlin" style="margin-left:10px;font-size:20pt;">Dan Wahlin's Blog</a> </div> <br /><br /><br /> <div style="clear:both;margin-top:20px;"> <uc:BlogRoller ID="BlogRoller" runat="server" /> </div> </div> </div> Of course, we wouldn’t want the RSS HTML content to be shown until requested. Once it’s requested the absolute position of where it should show above the Silverlight control can be set using standard CSS styles. The following ID selector named #RSSDiv handles hiding the overlay div shown above and determines where it will be display on the screen. #RSSDiv { background-color:White; position:absolute; top:100px; left:300px; width:800px; height:600px; border:1px solid black; display:none; } Now that the HTML content to display above the Silverlight control is set, how can we show it as a user clicks a HyperlinkButton or other control in the application? Fortunately, Silverlight provides an excellent HTML bridge that allows direct access to content hosted within a page. The following code shows two JavaScript functions that can be called from Siverlight to handle showing or hiding HTML overlay content. The two functions rely on jQuery (http://www.jQuery.com) to make it easy to select HTML objects and manipulate their properties: function ShowOverlay() { rssDiv.css('display', 'block'); } function HideOverlay() { rssDiv.css('display', 'none'); } Calling the ShowOverlay function is as simple as adding the following code into the Silverlight application within a button’s Click event handler: private void OverlayHyperlinkButton_Click(object sender, RoutedEventArgs e) { HtmlPage.Window.Invoke("ShowOverlay"); } The result of setting the Silverlight control’s windowless parameter to true and showing the HTML overlay content is shown in the following screenshot: Thinking Outside the Box to Show HTML Content Setting the windowless parameter to true may not be a viable option for some Silverlight applications or you may simply want to go about showing HTML content a different way. The next technique I’ll show takes advantage of simple HTML, CSS and JavaScript code to handle showing HTML content while a Silverlight application is running in the browser. Keep in mind that with Silverlight’s HTML bridge feature you can always pop-up HTML content in a new browser window using code similar to the following: System.Windows.Browser.HtmlPage.Window.Navigate( new Uri("http://silverlight.net"), "_blank"); For this example I’ll demonstrate how to hide the Silverlight application while maximizing a container div containing the HTML content to show. This allows HTML content to take up the full screen area of the browser without having to set windowless to true and when done right can make the user feel like they never left the Silverlight application. The following HTML shows several div elements that are used to display HTML within the same browser window as the Silverlight application: <div id="JobPlanDiv"> <div style="vertical-align:middle"> <img alt="Close Button" align="right" src="Images/Close.png" onclick="HideJobPlanIFrame();" style="cursor:pointer;" /> </div> <div id="JobPlan_IFrame_Container" style="height:95%;width:100%;margin-top:37px;"></div> </div> The JobPlanDiv element acts as a container for two other divs that handle showing a close button and hosting an iframe that will be added dynamically at runtime. JobPlanDiv isn’t visible when the Silverlight application loads due to the following ID selector added into the page: #JobPlanDiv { position:absolute; background-color:#484848; overflow:hidden; left:0; top:0; height:100%; width:100%; display:none; } When the HTML content needs to be shown or hidden the JavaScript functions shown next can be used: var jobPlanIFrameID = 'JobPlan_IFrame'; var slHost = null; var jobPlanContainer = null; var jobPlanIFrameContainer = null; var rssDiv = null; $(document).ready(function () { slHost = $('#silverlightControlHost'); jobPlanContainer = $('#JobPlanDiv'); jobPlanIFrameContainer = $('#JobPlan_IFrame_Container'); rssDiv = $('#RSSDiv'); }); function ShowJobPlanIFrame(url) { jobPlanContainer.css('display', 'block'); $('<iframe id="' + jobPlanIFrameID + '" src="' + url + '" style="height:100%;width:100%;" />') .appendTo(jobPlanIFrameContainer); slHost.css('width', '0%'); } function HideJobPlanIFrame() { jobPlanContainer.css('display', 'none'); $('#' + jobPlanIFrameID).remove(); slHost.css('width', '100%'); } ShowJobPlanIFrame() handles showing the JobPlanDiv div and adding an iframe into it dynamically. Once JobPlanDiv is shown, the Silverlight control host has its width set to a value of 0% to allow the control to stay alive while making it invisible to the user. I found that this technique works better across multiple browsers as opposed to manipulating the Silverlight control host div’s display or visibility properties. Now that you’ve seen the code to handle showing and hiding the HTML content area, let’s switch focus to the Silverlight application. As a user clicks on a link such as “View Report” the ShowJobPlanIFrame() JavaScript function needs to be called. The following code handles that task: private void ReportHyperlinkButton_Click(object sender, RoutedEventArgs e) { ShowBrowser(_BaseUrl + "/Report.aspx"); } public void ShowBrowser(string url) { HtmlPage.Window.Invoke("ShowJobPlanIFrame", url); } Any URL can be passed into the ShowBrowser() method which handles invoking the JavaScript function. This includes standard web pages or even PDF files. We’ve used this technique frequently with our SmartPrint control (http://www.smartwebcontrols.com) which converts Silverlight screens into PDF documents and displays them. Here’s an example of the content generated: Silverlight 4’s WebBrowser Control Both techniques shown to this point work well when Silverlight is running in-browser but not so well when it’s running out-of-browser since there’s no host page that you can access using the HTML bridge. Fortunately, Silverlight 4 provides a WebBrowser control that can be used to perform the same functionality quite easily. We’re currently using it in client applications to display PDF documents, SSRS reports and standard HTML content. Using the WebBrowser control simplifies the application quite a bit since no JavaScript is required if the application only runs out-of-browser. Here’s a simple example of defining the WebBrowser control in XAML. I typically define it in MainPage.xaml when a Silverlight Navigation template is used to create the project so that I can re-use the functionality across multiple screens. <Grid x:Name="WebBrowserGrid" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Visibility="Collapsed"> <StackPanel HorizontalAlignment="Stretch" VerticalAlignment="Stretch"> <Border Background="#484848" HorizontalAlignment="Stretch" Height="40"> <Image x:Name="WebBrowserImage" Width="100" Height="33" Cursor="Hand" HorizontalAlignment="Right" Source="/HTMLAndSilverlight;component/Assets/Images/Close.png" MouseLeftButtonDown="WebBrowserImage_MouseLeftButtonDown" /> </Border> <WebBrowser x:Name="JobPlanReportWebBrowser" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" /> </StackPanel> </Grid> Looking through the XAML you can see that a close image is defined along with the WebBrowser control. Because the URL that the WebBrowser should navigate to isn’t known at design time no value is assigned to the control’s Source property. If the XAML shown above is left “as is” you’ll find that any HTML content assigned to the WebBrowser doesn’t display properly. This is due to no height or width being set on the control. To handle this issue the following code is added into the XAML’s code-behind file to dynamically determine the height and width of the page and assign it to the WebBrowser. This is done by handling the SizeChanged event. void MainPage_SizeChanged(object sender, SizeChangedEventArgs e) { WebBrowserGrid.Height = JobPlanReportWebBrowser.Height = ActualHeight; WebBrowserGrid.Width = JobPlanReportWebBrowser.Width = ActualWidth; } When the user wants to view HTML content they click a button which executes the code shown in next: public void ShowBrowser(string url) { if (Application.Current.IsRunningOutOfBrowser) { JobPlanReportWebBrowser.NavigateToString("<html><body><iframe src='" + url + "' style='width:100%;height:97%;' /></body></html>"); WebBrowserGrid.Visibility = Visibility.Visible; } else { HtmlPage.Window.Invoke("ShowJobPlanIFrame", url); } } private void WebBrowserImage_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { WebBrowserGrid.Visibility = Visibility.Collapsed; } Looking through the code you’ll see that it checks to see if the Silverlight application is running out-of-browser and then either displays the WebBrowser control or runs the JavaScript function discussed earlier. Although the WebBrowser control’s Source property could be assigned the URI of the page to navigate to, by assigning HTML content using the NavigateToString() method and adding an iframe, content can be shown from any site including cross-domain sites. This is especially handy when you need to grab a page from a reporting site that’s in a different domain than the Silverlight application. Here’s an example of viewing PDF file inside of an out-of-browser application. The first image shows the application running out-of-browser before the user clicks a PDF HyperlinkButton. The second image shows the PDF being displayed. While there are certainly other techniques that can be used, the ones shown here have worked well for us in different applications and provide the ability to display HTML content in-browser or out-of-browser. Feel free to add a comment if you have another tip or trick you like to use when working with HTML content in Silverlight applications. Download Code Sample For more information about onsite, online and video training, mentoring and consulting solutions for .NET, SharePoint or Silverlight please visit http://www.thewahlingroup.com.

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Creating a dynamic, extensible C# Expando Object

- by Rick Strahl

I love dynamic functionality in a strongly typed language because it offers us the best of both worlds. In C# (or any of the main .NET languages) we now have the dynamic type that provides a host of dynamic features for the static C# language. One place where I've found dynamic to be incredibly useful is in building extensible types or types that expose traditionally non-object data (like dictionaries) in easier to use and more readable syntax. I wrote about a couple of these for accessing old school ADO.NET DataRows and DataReaders more easily for example. These classes are dynamic wrappers that provide easier syntax and auto-type conversions which greatly simplifies code clutter and increases clarity in existing code. ExpandoObject in .NET 4.0 Another great use case for dynamic objects is the ability to create extensible objects - objects that start out with a set of static members and then can add additional properties and even methods dynamically. The .NET 4.0 framework actually includes an ExpandoObject class which provides a very dynamic object that allows you to add properties and methods on the fly and then access them again. For example with ExpandoObject you can do stuff like this:dynamic expand = new ExpandoObject(); expand.Name = "Rick"; expand.HelloWorld = (Func<string, string>) ((string name) => { return "Hello " + name; }); Console.WriteLine(expand.Name); Console.WriteLine(expand.HelloWorld("Dufus")); Internally ExpandoObject uses a Dictionary like structure and interface to store properties and methods and then allows you to add and access properties and methods easily. As cool as ExpandoObject is it has a few shortcomings too: It's a sealed type so you can't use it as a base class It only works off 'properties' in the internal Dictionary - you can't expose existing type data It doesn't serialize to XML or with DataContractSerializer/DataContractJsonSerializer Expando - A truly extensible Object ExpandoObject is nice if you just need a dynamic container for a dictionary like structure. However, if you want to build an extensible object that starts out with a set of strongly typed properties and then allows you to extend it, ExpandoObject does not work because it's a sealed class that can't be inherited. I started thinking about this very scenario for one of my applications I'm building for a customer. In this system we are connecting to various different user stores. Each user store has the same basic requirements for username, password, name etc. But then each store also has a number of extended properties that is available to each application. In the real world scenario the data is loaded from the database in a data reader and the known properties are assigned from the known fields in the database. All unknown fields are then 'added' to the expando object dynamically. In the past I've done this very thing with a separate property - Properties - just like I do for this class. But the property and dictionary syntax is not ideal and tedious to work with. I started thinking about how to represent these extra property structures. One way certainly would be to add a Dictionary, or an ExpandoObject to hold all those extra properties. But wouldn't it be nice if the application could actually extend an existing object that looks something like this as you can with the Expando object:public class User : Westwind.Utilities.Dynamic.Expando { public string Email { get; set; } public string Password { get; set; } public string Name { get; set; } public bool Active { get; set; } public DateTime? ExpiresOn { get; set; } } and then simply start extending the properties of this object dynamically? Using the Expando object I describe later you can now do the following:[TestMethod] public void UserExampleTest() { var user = new User(); // Set strongly typed properties user.Email = "[email protected]"; user.Password = "nonya123"; user.Name = "Rickochet"; user.Active = true; // Now add dynamic properties dynamic duser = user; duser.Entered = DateTime.Now; duser.Accesses = 1; // you can also add dynamic props via indexer user["NickName"] = "AntiSocialX"; duser["WebSite"] = "http://www.west-wind.com/weblog"; // Access strong type through dynamic ref Assert.AreEqual(user.Name,duser.Name); // Access strong type through indexer Assert.AreEqual(user.Password,user["Password"]); // access dyanmically added value through indexer Assert.AreEqual(duser.Entered,user["Entered"]); // access index added value through dynamic Assert.AreEqual(user["NickName"],duser.NickName); // loop through all properties dynamic AND strong type properties (true) foreach (var prop in user.GetProperties(true)) { object val = prop.Value; if (val == null) val = "null"; Console.WriteLine(prop.Key + ": " + val.ToString()); } } As you can see this code somewhat blurs the line between a static and dynamic type. You start with a strongly typed object that has a fixed set of properties. You can then cast the object to dynamic (as I discussed in my last post) and add additional properties to the object. You can also use an indexer to add dynamic properties to the object. To access the strongly typed properties you can use either the strongly typed instance, the indexer or the dynamic cast of the object. Personally I think it's kinda cool to have an easy way to access strongly typed properties by string which can make some data scenarios much easier. To access the 'dynamically added' properties you can use either the indexer on the strongly typed object, or property syntax on the dynamic cast. Using the dynamic type allows all three modes to work on both strongly typed and dynamic properties. Finally you can iterate over all properties, both dynamic and strongly typed if you chose. Lots of flexibility. Note also that by default the Expando object works against the (this) instance meaning it extends the current object. You can also pass in a separate instance to the constructor in which case that object will be used to iterate over to find properties rather than this. Using this approach provides some really interesting functionality when use the dynamic type. To use this we have to add an explicit constructor to the Expando subclass:public class User : Westwind.Utilities.Dynamic.Expando { public string Email { get; set; } public string Password { get; set; } public string Name { get; set; } public bool Active { get; set; } public DateTime? ExpiresOn { get; set; } public User() : base() { } // only required if you want to mix in seperate instance public User(object instance) : base(instance) { } } to allow the instance to be passed. When you do you can now do:[TestMethod] public void ExpandoMixinTest() { // have Expando work on Addresses var user = new User( new Address() ); // cast to dynamicAccessToPropertyTest dynamic duser = user; // Set strongly typed properties duser.Email = "[email protected]"; user.Password = "nonya123"; // Set properties on address object duser.Address = "32 Kaiea"; //duser.Phone = "808-123-2131"; // set dynamic properties duser.NonExistantProperty = "This works too"; // shows default value Address.Phone value Console.WriteLine(duser.Phone); } Using the dynamic cast in this case allows you to access *three* different 'objects': The strong type properties, the dynamically added properties in the dictionary and the properties of the instance passed in! Effectively this gives you a way to simulate multiple inheritance (which is scary - so be very careful with this, but you can do it). How Expando works Behind the scenes Expando is a DynamicObject subclass as I discussed in my last post. By implementing a few of DynamicObject's methods you can basically create a type that can trap 'property missing' and 'method missing' operations. When you access a non-existant property a known method is fired that our code can intercept and provide a value for. Internally Expando uses a custom dictionary implementation to hold the dynamic properties you might add to your expandable object. Let's look at code first. The code for the Expando type is straight forward and given what it provides relatively short. Here it is.using System; using System.Collections.Generic; using System.Linq; using System.Dynamic; using System.Reflection; namespace Westwind.Utilities.Dynamic { /// <summary> /// Class that provides extensible properties and methods. This /// dynamic object stores 'extra' properties in a dictionary or /// checks the actual properties of the instance. /// /// This means you can subclass this expando and retrieve either /// native properties or properties from values in the dictionary. /// /// This type allows you three ways to access its properties: /// /// Directly: any explicitly declared properties are accessible /// Dynamic: dynamic cast allows access to dictionary and native properties/methods /// Dictionary: Any of the extended properties are accessible via IDictionary interface /// </summary> [Serializable] public class Expando : DynamicObject, IDynamicMetaObjectProvider { /// <summary> /// Instance of object passed in /// </summary> object Instance; /// <summary> /// Cached type of the instance /// </summary> Type InstanceType; PropertyInfo[] InstancePropertyInfo { get { if (_InstancePropertyInfo == null && Instance != null) _InstancePropertyInfo = Instance.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly); return _InstancePropertyInfo; } } PropertyInfo[] _InstancePropertyInfo; /// <summary> /// String Dictionary that contains the extra dynamic values /// stored on this object/instance /// </summary> /// <remarks>Using PropertyBag to support XML Serialization of the dictionary</remarks> public PropertyBag Properties = new PropertyBag(); //public Dictionary<string,object> Properties = new Dictionary<string, object>(); /// <summary> /// This constructor just works off the internal dictionary and any /// public properties of this object. /// /// Note you can subclass Expando. /// </summary> public Expando() { Initialize(this); } /// <summary> /// Allows passing in an existing instance variable to 'extend'. /// </summary> /// <remarks> /// You can pass in null here if you don't want to /// check native properties and only check the Dictionary! /// </remarks> /// <param name="instance"></param> public Expando(object instance) { Initialize(instance); } protected virtual void Initialize(object instance) { Instance = instance; if (instance != null) InstanceType = instance.GetType(); } /// <summary> /// Try to retrieve a member by name first from instance properties /// followed by the collection entries. /// </summary> /// <param name="binder"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; // first check the Properties collection for member if (Properties.Keys.Contains(binder.Name)) { result = Properties[binder.Name]; return true; } // Next check for Public properties via Reflection if (Instance != null) { try { return GetProperty(Instance, binder.Name, out result); } catch { } } // failed to retrieve a property result = null; return false; } /// <summary> /// Property setter implementation tries to retrieve value from instance /// first then into this object /// </summary> /// <param name="binder"></param> /// <param name="value"></param> /// <returns></returns> public override bool TrySetMember(SetMemberBinder binder, object value) { // first check to see if there's a native property to set if (Instance != null) { try { bool result = SetProperty(Instance, binder.Name, value); if (result) return true; } catch { } } // no match - set or add to dictionary Properties[binder.Name] = value; return true; } /// <summary> /// Dynamic invocation method. Currently allows only for Reflection based /// operation (no ability to add methods dynamically). /// </summary> /// <param name="binder"></param> /// <param name="args"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { if (Instance != null) { try { // check instance passed in for methods to invoke if (InvokeMethod(Instance, binder.Name, args, out result)) return true; } catch { } } result = null; return false; } /// <summary> /// Reflection Helper method to retrieve a property /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="result"></param> /// <returns></returns> protected bool GetProperty(object instance, string name, out object result) { if (instance == null) instance = this; var miArray = InstanceType.GetMember(name, BindingFlags.Public | BindingFlags.GetProperty | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0]; if (mi.MemberType == MemberTypes.Property) { result = ((PropertyInfo)mi).GetValue(instance,null); return true; } } result = null; return false; } /// <summary> /// Reflection helper method to set a property value /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="value"></param> /// <returns></returns> protected bool SetProperty(object instance, string name, object value) { if (instance == null) instance = this; var miArray = InstanceType.GetMember(name, BindingFlags.Public | BindingFlags.SetProperty | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0]; if (mi.MemberType == MemberTypes.Property) { ((PropertyInfo)mi).SetValue(Instance, value, null); return true; } } return false; } /// <summary> /// Reflection helper method to invoke a method /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="args"></param> /// <param name="result"></param> /// <returns></returns> protected bool InvokeMethod(object instance, string name, object[] args, out object result) { if (instance == null) instance = this; // Look at the instanceType var miArray = InstanceType.GetMember(name, BindingFlags.InvokeMethod | BindingFlags.Public | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0] as MethodInfo; result = mi.Invoke(Instance, args); return true; } result = null; return false; } /// <summary> /// Convenience method that provides a string Indexer /// to the Properties collection AND the strongly typed /// properties of the object by name. /// /// // dynamic /// exp["Address"] = "112 nowhere lane"; /// // strong /// var name = exp["StronglyTypedProperty"] as string; /// </summary> /// <remarks> /// The getter checks the Properties dictionary first /// then looks in PropertyInfo for properties. /// The setter checks the instance properties before /// checking the Properties dictionary. /// </remarks> /// <param name="key"></param> /// /// <returns></returns> public object this[string key] { get { try { // try to get from properties collection first return Properties[key]; } catch (KeyNotFoundException ex) { // try reflection on instanceType object result = null; if (GetProperty(Instance, key, out result)) return result; // nope doesn't exist throw; } } set { if (Properties.ContainsKey(key)) { Properties[key] = value; return; } // check instance for existance of type first var miArray = InstanceType.GetMember(key, BindingFlags.Public | BindingFlags.GetProperty); if (miArray != null && miArray.Length > 0) SetProperty(Instance, key, value); else Properties[key] = value; } } /// <summary> /// Returns and the properties of /// </summary> /// <param name="includeProperties"></param> /// <returns></returns> public IEnumerable<KeyValuePair<string,object>> GetProperties(bool includeInstanceProperties = false) { if (includeInstanceProperties && Instance != null) { foreach (var prop in this.InstancePropertyInfo) yield return new KeyValuePair<string, object>(prop.Name, prop.GetValue(Instance, null)); } foreach (var key in this.Properties.Keys) yield return new KeyValuePair<string, object>(key, this.Properties[key]); } /// <summary> /// Checks whether a property exists in the Property collection /// or as a property on the instance /// </summary> /// <param name="item"></param> /// <returns></returns> public bool Contains(KeyValuePair<string, object> item, bool includeInstanceProperties = false) { bool res = Properties.ContainsKey(item.Key); if (res) return true; if (includeInstanceProperties && Instance != null) { foreach (var prop in this.InstancePropertyInfo) { if (prop.Name == item.Key) return true; } } return false; } } } Although the Expando class supports an indexer, it doesn't actually implement IDictionary or even IEnumerable. It only provides the indexer and Contains() and GetProperties() methods, that work against the Properties dictionary AND the internal instance. The reason for not implementing IDictionary is that a) it doesn't add much value since you can access the Properties dictionary directly and that b) I wanted to keep the interface to class very lean so that it can serve as an entity type if desired. Implementing these IDictionary (or even IEnumerable) causes LINQ extension methods to pop up on the type which obscures the property interface and would only confuse the purpose of the type. IDictionary and IEnumerable are also problematic for XML and JSON Serialization - the XML Serializer doesn't serialize IDictionary<string,object>, nor does the DataContractSerializer. The JavaScriptSerializer does serialize, but it treats the entire object like a dictionary and doesn't serialize the strongly typed properties of the type, only the dictionary values which is also not desirable. Hence the decision to stick with only implementing the indexer to support the user["CustomProperty"] functionality and leaving iteration functions to the publicly exposed Properties dictionary. Note that the Dictionary used here is a custom PropertyBag class I created to allow for serialization to work. One important aspect for my apps is that whatever custom properties get added they have to be accessible to AJAX clients since the particular app I'm working on is a SIngle Page Web app where most of the Web access is through JSON AJAX calls. PropertyBag can serialize to XML and one way serialize to JSON using the JavaScript serializer (not the DCS serializers though). The key components that make Expando work in this code are the Properties Dictionary and the TryGetMember() and TrySetMember() methods. The Properties collection is public so if you choose you can explicitly access the collection to get better performance or to manipulate the members in internal code (like loading up dynamic values form a database). Notice that TryGetMember() and TrySetMember() both work against the dictionary AND the internal instance to retrieve and set properties. This means that user["Name"] works against native properties of the object as does user["Name"] = "RogaDugDog". What's your Use Case? This is still an early prototype but I've plugged it into one of my customer's applications and so far it's working very well. The key features for me were the ability to easily extend the type with values coming from a database and exposing those values in a nice and easy to use manner. I'm also finding that using this type of object for ViewModels works very well to add custom properties to view models. I suspect there will be lots of uses for this - I've been using the extra dictionary approach to extensibility for years - using a dynamic type to make the syntax cleaner is just a bonus here. What can you think of to use this for? Resources Source Code and Tests (GitHub) Also integrated in Westwind.Utilities of the West Wind Web Toolkit West Wind Utilities NuGet© Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp .NET Dynamic Types Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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NoSQL with RavenDB and ASP.NET MVC - Part 1

- by shiju

A while back, I have blogged NoSQL with MongoDB, NoRM and ASP.NET MVC Part 1 and Part 2 on how to use MongoDB with an ASP.NET MVC application. The NoSQL movement is getting big attention and RavenDB is the latest addition to the NoSQL and document database world. RavenDB is an Open Source (with a commercial option) document database for the .NET/Windows platform developed by Ayende Rahien. Raven stores schema-less JSON documents, allow you to define indexes using Linq queries and focus on low latency and high performance. RavenDB is .NET focused document database which comes with a fully functional .NET client API and supports LINQ. RavenDB comes with two components, a server and a client API. RavenDB is a REST based system, so you can write your own HTTP cleint API. As a .NET developer, RavenDB is becoming my favorite document database. Unlike other document databases, RavenDB is supports transactions using System.Transactions. Also it's supports both embedded and server mode of database. You can access RavenDB site at http://ravendb.netA demo App with ASP.NET MVCLet's create a simple demo app with RavenDB and ASP.NET MVC. To work with RavenDB, do the following steps. Go to http://ravendb.net/download and download the latest build.Unzip the downloaded file.Go to the /Server directory and run the RavenDB.exe. This will start the RavenDB server listening on localhost:8080You can change the port of RavenDB by modifying the "Raven/Port" appSetting value in the RavenDB.exe.config file.When running the RavenDB, it will automatically create a database in the /Data directory. You can change the directory name data by modifying "Raven/DataDirt" appSetting value in the RavenDB.exe.config file.RavenDB provides a browser based admin tool. When the Raven server is running, You can be access the browser based admin tool and view and edit documents and index using your browser admin tool. The web admin tool available at http://localhost:8080The below is the some screen shots of web admin tool Working with ASP.NET MVC To working with RavenDB in our demo ASP.NET MVC application, do the following steps Step 1 - Add reference to Raven Cleint API In our ASP.NET MVC application, Add a reference to the Raven.Client.Lightweight.dll from the Client directory. Step 2 - Create DocumentStoreThe document store would be created once per application. Let's create a DocumentStore on application start-up in the Global.asax.cs. documentStore = new DocumentStore { Url = "http://localhost:8080/" }; documentStore.Initialise(); The above code will create a Raven DB document store and will be listening the server locahost at port 8080 Step 3 - Create DocumentSession on BeginRequest Let's create a DocumentSession on BeginRequest event in the Global.asax.cs. We are using the document session for every unit of work. In our demo app, every HTTP request would be a single Unit of Work (UoW). BeginRequest += (sender, args) => HttpContext.Current.Items[RavenSessionKey] = documentStore.OpenSession(); Step 4 - Destroy the DocumentSession on EndRequest EndRequest += (o, eventArgs) => { var disposable = HttpContext.Current.Items[RavenSessionKey] as IDisposable; if (disposable != null) disposable.Dispose(); }; At the end of HTTP request, we are destroying the DocumentSession object.The below code block shown all the code in the Global.asax.cs private const string RavenSessionKey = "RavenMVC.Session"; private static DocumentStore documentStore; protected void Application_Start() { //Create a DocumentStore in Application_Start //DocumentStore should be created once per application and stored as a singleton. documentStore = new DocumentStore { Url = "http://localhost:8080/" }; documentStore.Initialise(); AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); //DI using Unity 2.0 ConfigureUnity(); } public MvcApplication() { //Create a DocumentSession on BeginRequest //create a document session for every unit of work BeginRequest += (sender, args) => HttpContext.Current.Items[RavenSessionKey] = documentStore.OpenSession(); //Destroy the DocumentSession on EndRequest EndRequest += (o, eventArgs) => { var disposable = HttpContext.Current.Items[RavenSessionKey] as IDisposable; if (disposable != null) disposable.Dispose(); }; } //Getting the current DocumentSession public static IDocumentSession CurrentSession { get { return (IDocumentSession)HttpContext.Current.Items[RavenSessionKey]; } } We have setup all necessary code in the Global.asax.cs for working with RavenDB. For our demo app, Let’s write a domain class public class Category { public string Id { get; set; } [Required(ErrorMessage = "Name Required")] [StringLength(25, ErrorMessage = "Must be less than 25 characters")] public string Name { get; set;} public string Description { get; set; } } We have created simple domain entity Category. Let's create repository class for performing CRUD operations against our domain entity Category. public interface ICategoryRepository { Category Load(string id); IEnumerable<Category> GetCategories(); void Save(Category category); void Delete(string id); } public class CategoryRepository : ICategoryRepository { private IDocumentSession session; public CategoryRepository() { session = MvcApplication.CurrentSession; } //Load category based on Id public Category Load(string id) { return session.Load<Category>(id); } //Get all categories public IEnumerable<Category> GetCategories() { var categories= session.LuceneQuery<Category>() .WaitForNonStaleResults() .ToArray(); return categories; } //Insert/Update category public void Save(Category category) { if (string.IsNullOrEmpty(category.Id)) { //insert new record session.Store(category); } else { //edit record var categoryToEdit = Load(category.Id); categoryToEdit.Name = category.Name; categoryToEdit.Description = category.Description; } //save the document session session.SaveChanges(); } //delete a category public void Delete(string id) { var category = Load(id); session.Delete<Category>(category); session.SaveChanges(); } } For every CRUD operations, we are taking the current document session object from HttpContext object. session = MvcApplication.CurrentSession; We are calling the static method CurrentSession from the Global.asax.cs public static IDocumentSession CurrentSession { get { return (IDocumentSession)HttpContext.Current.Items[RavenSessionKey]; } } Retrieve Entities The Load method get the single Category object based on the Id. RavenDB is working based on the REST principles and the Id would be like categories/1. The Id would be created by automatically when a new object is inserted to the document store. The REST uri categories/1 represents a single category object with Id representation of 1. public Category Load(string id) { return session.Load<Category>(id); } The GetCategories method returns all the categories calling the session.LuceneQuery method. RavenDB is using a lucen query syntax for querying. I will explain more details about querying and indexing in my future posts. public IEnumerable<Category> GetCategories() { var categories= session.LuceneQuery<Category>() .WaitForNonStaleResults() .ToArray(); return categories; } Insert/Update entityFor insert/Update a Category entity, we have created Save method in repository class. If the Id property of Category is null, we call Store method of Documentsession for insert a new record. For editing a existing record, we load the Category object and assign the values to the loaded Category object. The session.SaveChanges() will save the changes to document store. //Insert/Update category public void Save(Category category) { if (string.IsNullOrEmpty(category.Id)) { //insert new record session.Store(category); } else { //edit record var categoryToEdit = Load(category.Id); categoryToEdit.Name = category.Name; categoryToEdit.Description = category.Description; } //save the document session session.SaveChanges(); } Delete Entity In the Delete method, we call the document session's delete method and call the SaveChanges method to reflect changes in the document store. public void Delete(string id) { var category = Load(id); session.Delete<Category>(category); session.SaveChanges(); } Let’s create ASP.NET MVC controller and controller actions for handling CRUD operations for the domain class Category public class CategoryController : Controller { private ICategoryRepository categoyRepository; //DI enabled constructor public CategoryController(ICategoryRepository categoyRepository) { this.categoyRepository = categoyRepository; } public ActionResult Index() { var categories = categoyRepository.GetCategories(); if (categories == null) return RedirectToAction("Create"); return View(categories); } [HttpGet] public ActionResult Edit(string id) { var category = categoyRepository.Load(id); return View("Save",category); } // GET: /Category/Create [HttpGet] public ActionResult Create() { var category = new Category(); return View("Save", category); } [HttpPost] public ActionResult Save(Category category) { if (!ModelState.IsValid) { return View("Save", category); } categoyRepository.Save(category); return RedirectToAction("Index"); } [HttpPost] public ActionResult Delete(string id) { categoyRepository.Delete(id); var categories = categoyRepository.GetCategories(); return PartialView("CategoryList", categories); } } RavenDB is an awesome document database and I hope that it will be the winner in .NET space of document database world. The source code of demo application available at http://ravenmvc.codeplex.com/

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