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  • How do I assign by "reference" to a class field in c#?

    - by Jamie
    I am trying to understand how to assign by "reference" to a class field in c#. I have the follwing example to consider: public class X { public X() { string example = "X"; new Y( ref example ); new Z( ref example ); System.Diagnostics.Debug.WriteLine( example ); } } public class Y { public Y( ref string example ) { example += " (Updated By Y)"; } } public class Z { private string _Example; public Z( ref string example ) { this._Example = example; this._Example += " (Updated By Z)"; } } var x = new X(); When running the above code the output is: X (Updated By Y) And not: X (Updated By Y) (Updated By Z) As I had hoped. It seems that assigning a "ref parameter" to a field loses the reference. Is there any way to keep hold of the reference when assigning to a field? Thanks.

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  • Code Design question, circular reference across classes?

    - by dsollen
    I have no code here, as this is more of a design question (I assume this is still the best place to ask it). I have a very simple server in java which stores a mapping between certain values and UUID which are to be used by many systems across multiple platforms. It accepts a connection from a client and creates a clientSocket which stores the socket and all the other relevant data unique to that connection. Each clientSocket will run in their own thread and will block on the socket waiting for a read. I expect very little strain on this system, it will rarely get called, but when it does get a call it will need to respond quickly and due to the risk of it having a peak time with multiple calls coming in at once threaded is still better. Each thread has a reference to a Mapper class which stores the mapping of UUID which it's reporting to others (with proper synchronization of course). This all works until I have to add a new UUID to the list. When this happens I want to report to all clients that care about that particular UUID that a new one was added. I can't multicast (limitation of the system I'm running on) so I'm having each socket send the message to the client through the established socket. However, since each thread only knows about the socket it's waiting on I didn't have a clear method of looking up every thread/socket that cares about the data to inform them of the new UUID. Polling is out mostly because it seems a little too convoluted to try to maintain a list of newly added UUID. My solution as of now is to have the 'parent' class which creates the mapper class and spawns all the threads pass itself as an argument to the mapper. Then when the mapper creates a new UUID it can make a call to the parent class telling it to send out updates to all the other sockets that care about the change. I'm concerned that this may be a bad design due to the use of a circular reference; parent has a reference to mapper (to pass it to new ClientSocket threads) and mapper points to parent. It doesn't really feel like a bad design to me but I wanted to check since circular references are suppose to be bad. Note: I realize this means that the thread associated with whatever socket originally received the request that spawned the creation of a UUID is going to pay the 'cost' of outputting to all the other clients that care about the new UUID. I don't care about this; as I said I suspect the client to receive only intermittent messages. It's unlikely for one socket to receive multiple messages at one time, and there won't be that many sockets so it shouldn't take too long to send messages to each of them. Perhaps later I'll fix the fact that I'm saddling higher work load on whatever unfortunate thread gets the first request; but for now I think it's fine.

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  • reference list for non-IT driven algorithmic patterns

    - by Quicker
    I am looking for a reference list for non-IT driven algorithmic patterns (which still can be helped with IT implementations of IT). An Example List would be: name; short desc; reference Travelling Salesman; find the shortest possible route on a multiple target path; http://en.wikipedia.org/wiki/Travelling_salesman_problem Ressource Disposition (aka Regulation); Distribute a limited/exceeding input on a given number output receivers based on distribution rules; http://database-programmer.blogspot.de/2010/12/critical-analysis-of-algorithm-sproc.html If there is no such list, but you instantly think of something specific, please 'put it on the desk'. Maybe I can compile something out of the input I get here (actually I am very frustrated as I did not find any such list via research by myself). Details on Scoping: I found it very hard to formulate what I want in a way everything is out that I do not need (which may be the issue why I did not find anything at google). There is a database centric definition for what I am looking for in the section 'Processes' of the second example link. That somehow fits, but the database focus sort of drifts away from the pattern thinking, which I have in mind. So here are my own thoughts around what's in and what's out: I am NOT looking for a foundational algo ref list, which is implemented as basis for any programming language. Eg. the php reference describes substr and strlen. That implements algos, but is not what I am looking for. the problem the algo does address would even exist, if there were no computers (or other IT components) the main focus of the algo is NOT to help other algo's chances are high, that there are implementions of the solution or any workaround without any IT support out there in the world however the algo could be benefitialy implemented/fully supported by a software application = means: the problem of the algo has to be addressed anyway, but running an algo implementation with software automates the process (that is why I posted it on stackoverflow and not somewhere else) typically such algo implementations have more than one input field value and more than one output field value - which implies it could not be implemented as simple function (which is fixed to produce not more than one output value) in a normalized data model often times such algo implementation outputs span accross multiple rows (sometimes multiple tables), whereby the number of output rows depends on the input paraters and rows in the table(s) at start time - which implies that any algo implementation/procedure must interact with a database (read and/or write) I am mainly looking for patterns, not for specific implementations. Example: The Travelling Salesman assumes any coordinates, however it does not say: You need a table targets with fields x and y. - however sometimes descriptions are focussed on examples with specific implementations very much - no worries, as long as the pattern gets clear

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  • How to get the field name of a java (weak) reference pointing to an object in an other class?

    - by Tom
    Imagine I have the following situation: Test1.java import java.lang.ref.WeakReference; public class Test1 { public WeakReference fieldName; public init() { fieldName = new WeakReference(this); Test2.setWeakRef(fieldName); } } Test2.java import java.lang.ref.WeakReference; public class Test2 { public static setWeakRef(WeakReference weakRef) { //at this point I got weakRef in an other class.. now, how do I get the field name this reference was created with? So that it returns exactly "fieldName", because that's the name I gave it in Test1.java? } } At the location of the comment I received the weak reference created in an other class. How would I retreive the field name that this weak reference was created with, in this case "fieldName"? Thanks in advance.

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  • game programming career, vc++ reference and future of it [closed]

    - by Pappu Bacha
    1) I have quite a lot of interest in game programming and I (to my thought) am quite good at programming skills, I have developed some console based animations and text based animation games (like copter-it, snake, and a music visualization), should I invest in game programming? I have 2 years at college left. 2) If I am to pursue a career in game programming, and I select to go only with c++ and DirectX, is it enough? is assembly language necessary? 3) is Visual C++ or MFC dead? should I invest in it or not? 4) I am unable to find any reference book for Visual C++ 2008 or later (just like C++ the complete reference book) I need a book that covers the basic fundamentals and covers the most of the libraries etc.

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  • Using a function with reference as a function with pointers?

    - by epatel
    Today I stumbled over a piece of code that looked horrifying to me. The pieces was chattered in different files, I have tried write the gist of it in a simple test case below. The code base is routinely scanned with FlexeLint on a daily basis, but this construct has been laying in the code since 2004. The thing is that a function implemented with a parameter passing using references is called as a function with a parameter passing using pointers...due to a function cast. The construct has worked since 2004 on Irix and now when porting it actually do work on Linux/gcc too. My question now. Is this a construct one can trust? I can understand if compiler constructors implement the reference passing as it was a pointer, but is it reliable? Are there hidden risks? Should I change the fref(..) to use pointers and risk braking anything in the process? What to you think? #include <iostream> using namespace std; // ---------------------------------------- // This will be passed as a reference in fref(..) struct string_struct { char str[256]; }; // ---------------------------------------- // Using pointer here! void fptr(const char *str) { cout << "fptr: " << str << endl; } // ---------------------------------------- // Using reference here! void fref(string_struct &str) { cout << "fref: " << str.str << endl; } // ---------------------------------------- // Cast to f(const char*) and call with pointer void ftest(void (*fin)()) { void (*fcall)(const char*) = (void(*)(const char*))fin; fcall("Hello!"); } // ---------------------------------------- // Let's go for a test int main() { ftest((void (*)())fptr); // test with fptr that's using pointer ftest((void (*)())fref); // test with fref that's using reference return 0; }

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  • Customize Team Build 2010 – Part 16: Specify the relative reference path

    In the series the following parts have been published Part 1: Introduction Part 2: Add arguments and variables Part 3: Use more complex arguments Part 4: Create your own activity Part 5: Increase AssemblyVersion Part 6: Use custom type for an argument Part 7: How is the custom assembly found Part 8: Send information to the build log Part 9: Impersonate activities (run under other credentials) Part 10: Include Version Number in the Build Number Part 11: Speed up opening my build process template Part 12: How to debug my custom activities Part 13: Get control over the Build Output Part 14: Execute a PowerShell script Part 15: Fail a build based on the exit code of a console application Part 16: Specify the relative reference path As I have already blogged about, it is not intuitive how to specify the paths where the build server has to look for references that are stored in Source Control. It is a common practice to store 3rd party libraries in Source Control, so they are available to everyone, everyone uses the same version of the libraries and updating a library can be done centrally. In Team Build 2010 these paths are specified as a parameter for MSBuild. What we will do in this post is building the values for this parameter based on the values in an argument. You are now pretty aware how to customize the build template, so let’s do the modifications in another way. Instead of opening the xaml file in the workflow designer, we open it in the XML editor. You can open it in the XML Editor by either selecting the Open with menu (see the context menu), or by choosing the View code option. To add this functionality we need to: Specify a new argument Add the argument to the metadata Build the absolute paths for the references and add these paths to the MSBuild arguments 1. Specify a new argument Locate at the top of the document the Members (which are the arguments) of the XAML and add the following line <x:Property Name="ReferencePaths" Type="InArgument(s:String[])" /> 2. Add the argument to the metadata Then locate the line <mtbw:ProcessParameterMetadataCollection> and paste the following line <mtbw:ProcessParameterMetadata Category="Misc" Description="The list of reference paths, relative to the root path in the Workspace mapping." DisplayName="Reference paths" ParameterName="ReferencePaths" /> 3. Build the absolute paths for the references and add these paths to the MSBuild arguments Now locate the place where the assignments are done to the variables used in the agent. And add the following lines after the last Assign activity         <Sequence DisplayName="Initialize ReferencePath" sap:VirtualizedContainerService.HintSize="464,428">           <Sequence.Variables>             <Variable x:TypeArguments="x:String" Name="ReferencePathsArgument">               <Variable.Default>                 <Literal x:TypeArguments="x:String" Value="" />               </Variable.Default>             </Variable>           </Sequence.Variables>           <sap:WorkflowViewStateService.ViewState>             <scg:Dictionary x:TypeArguments="x:String, x:Object">               <x:Boolean x:Key="IsExpanded">True</x:Boolean>             </scg:Dictionary>           </sap:WorkflowViewStateService.ViewState>           <ForEach x:TypeArguments="x:String" DisplayName="Iterate through the paths" sap:VirtualizedContainerService.HintSize="287,206" mtbwt:BuildTrackingParticipant.Importance="Low" Values="[ReferencePaths]">             <ActivityAction x:TypeArguments="x:String">               <ActivityAction.Argument>                 <DelegateInArgument x:TypeArguments="x:String" Name="path" />               </ActivityAction.Argument>               <Assign x:TypeArguments="x:String" DisplayName="Build ReferencePath argument" sap:VirtualizedContainerService.HintSize="257,100" mtbwt:BuildTrackingParticipant.Importance="Low"  To="[ReferencePathsArgument]" Value="[If(String.IsNullOrEmpty(ReferencePathsArgument), &quot;&quot;, ReferencePathsArgument + &quot;;&quot;) + IO.Path.Combine(SourcesDirectory, path)]" />             </ActivityAction>           </ForEach>           <Assign DisplayName="Append the reference paths to the MSBuild Arguments" sap:VirtualizedContainerService.HintSize="287,58">             <Assign.To>               <OutArgument x:TypeArguments="x:String">[MSBuildArguments]</OutArgument>             </Assign.To>             <Assign.Value>               <InArgument x:TypeArguments="x:String">[String.Format("{0} /p:ReferencePath=""{1}""", MSBuildArguments, ReferencePathsArgument)]</InArgument>             </Assign.Value>           </Assign>         </Sequence> Now you can use the template to specify the paths relative to SourcesDirectory. You can download the full solution at BuildProcess.zip. It will include the sources of every part and will continue to evolve.

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  • Combo/Input LOV displaying non-reference key value

    - by [email protected]
    Its a very common use-case of LOV that we want to diplay a non key value in the LOV but store the key value in the DB. I had to do the same in a sample application I was building. During implementation of this, I realized that there are multiple ways to achieve this.I am going to describe each of these below.Example : Lets take an example of our classic HR schema. I have 2 tables Employee and Department where Dno is the foreign key attribute in Employee that references Department table.I want to create a LOV for Deparment such that the List always displays Dname instead of Dno. However when I update it, it it should update the reference key Dno.To achieve this I had 3 alternative1) Approach 1 :Create a composite VO and add the attributes from Department into Employee using a join.Refer the blog http://andrejusb.blogspot.com/2009/11/defining-lov-on-reference-attribute-in.htmlPositives :1. Easy to implement and use.2. We can use this attribute directly in queries defined on new attribute i.e If i have to display this inside query panel.Negative : We have to create an additional Join on the VO.Ex:SELECT Employees.EMPLOYEE_ID,        Employees.FIRST_NAME,        Employees.LAST_NAME,        Employees.EMAIL,        Employees.PHONE_NUMBER,       Department.Dno,        Department.DnameFROM EMPLOYEES Employees, Department Department WHERE Employees.Dno = Department .Dno2) Approach 2 :

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  • WPF: How do I get a reference to a styled window control in code behind?

    - by Brad
    I have a window defined with a style: <Window x:Class="winBorderless" x:Name="winBorderless" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Local="clr-namespace:WindowStyle" Style="{StaticResource Window_Cartesia}" WindowStartupLocation="CenterScreen" BorderThickness="1" BorderBrush="#FF9CAAC1" Margin="5" Title="[Document Title]"> and the style defined in an application level dictionary: <Style x:Key="Window_Cartesia" TargetType="{x:Type Window}"> <Setter Property="WindowStyle" Value="None"/> <Setter Property="AllowsTransparency" Value="True"/> <Setter Property="Background" Value="Transparent"/> <EventSetter Event="Loaded" Handler="Loaded"/> <EventSetter Event="PreviewKeyDown" Handler="Preview_KeyDown"/> <EventSetter Event="MouseMove" Handler="FullScreen_MouseMove"/> <Setter Property="Template"> In code behind I have a reference to the Window instance set: Win = DirectCast(sender, winBorderless) This allows access to the window properties as the EventSetters pass references to the various controls. However, it doesn't provide for access to the controls defined in the style through the window reference as they don't exist there. So, what is the best way to reference a control through code behind that is defined in the style. I'd prefer not to iterate the trees to find them but ya gotta do....

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  • C# how to calculate hashcode from an object reference.

    - by Wayne
    Folks, here's a thorny problem for you! A part of the TickZoom system must collect instances of every type of object into a Dictionary< type. It is imperative that their equality and hash code be based on the instance of the object which means reference equality instead of value equality. The challenge is that some of the objects in the system have overridden Equals() and GetHashCode() for use as value equality and their internal values will change over time. That means that their Equals and GetHashCode are useless. How to solve this generically rather than intrusively? So far, We created a struct to wrap each object called ObjectHandle for hashing into the Dictionary. As you see below we implemented Equals() but the problem of how to calculate a hash code remains. public struct ObjectHandle : IEquatable<ObjectHandle>{ public object Object; public bool Equals(ObjectHandle other) { return object.ReferenceEquals(this.Object,other.Object); } } See? There is the method object.ReferenceEquals() which will compare reference equality without regard for any overridden Equals() implementation in the object. Now, how to calculate a matching GetHashCode() by only considering the reference without concern for any overridden GetHashCode() method? Ahh, I hope this give you an interesting puzzle. We're stuck over here. Sincerely, Wayne

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  • Webcast: Best Practices for Speeding Virtual Infrastructure Deployment with Oracle VM

    - by Honglin Su
    We announced Oracle VM Blade Cluster Reference Configuration last month, see the blog. The new Oracle VM blade cluster reference configuration can help reduce the time to deploy virtual infrastructure by up to 98 percent when compared to multi-vendor configurations. Customers and partners have shown lots of interests. Join Oracle's experts to learn the best practices for speeding virtual infrastructure deployment with Oracle VM, register the webcast (1/25/2011) here.   Virtualization has already been widely accepted as a means to increase IT flexibility and help IT services align better with changing business needs. The flexibility of a virtualized IT infrastructure enables new applications to be rapidly deployed, capacity to be easily scaled, and IT resources to be quickly redirected. The net result is that IT can bring greater value to the business, making virtualization an obvious win from a business perspective. However, building a virtualized infrastructure typically requires assembling and integrating multiple components (e.g. servers, storage, network, virtualization, and operating systems). This infrastructure must be deployed and tested before applications can even be installed. It can take weeks or months to plan, architect, configure, troubleshoot, and deploy a virtualized infrastructure. The process is not only time-consuming, but also error-prone, making it hard to achieve a timely and profitable return on investment.  Oracle is the only vendor that can offer a fully integrated virtualization infrastructure with all of the necessary hardware and software components. The Oracle VM blade cluster reference configuration is a single-vendor solution that addresses every layer of the virtualization stack with Oracle hardware and software components, see the figure below. It enables quick and easy deployment of the virtualized infrastructure using components that have been tested together and are all supported together by Oracle. To learn more about Oracle's virtualization offerings, visit http://oracle.com/virtualization.

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  • Atom feed validator keeps showing Self reference doesn't match document location

    - by Dino
    I am creating an atom feed, but when I validate it I keep getting: Self reference doesn't match document location and the specific line that is causing the error is: <link rel="self" type="application/atom+xml" href="http://www.example.com/test.rss"/> Please can anyone advise what the error is? Ps. I noticed an up arrow just at the end of that line. (presumably something to do with that bbut not sure)

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  • My Reference for Amy Lewis

    - by Denise McInerney
    The 2013 election campaign for the PASS Board of Directors is underway. There are seven qualified candidates running this year. They all offer a wealth of experience volunteering for PASS and the SQL Server community. One of these candidates, Amy Lewis, asked me to write a reference for her to include on her candidate application. I have a lot of experience working with Amy and was pleased to provide this reference: I enthusiastically support Amy Lewis as a candidate for the PASS Board of Directors. I have known and worked with Amy in various PASS' volunteer capacities for years, starting when we were both leaders of SIGs (the precursors to the Virtual Chapters.) In that time I have seen Amy grow as a leader, taking on increasing responsibility and developing her leadership skills in the process. From the Program Committee to the BI Virtual Chapter to her local user group's SQL Saturday Amy has demonstrated a capacity to organize and lead volunteers. A successful leader delivers results, and does so in a way that encourages and empowers the people she is working with; Amy embodies this leadership style. As Director for Virtual Chapters I have most recently worked with Amy in her capacity of DW/BI VC Leader. This VC is one of our largest and most active, and Amy's leadership is a key contribution to that success. I was pleased to see that Amy was also thinking about succession and prepared other volunteers to take over the chapter leadership. Amy has shown an understanding of PASS' strategic goals and has focused her volunteer efforts to help us reach those goals. For the past couple of years we have been trying to expand PASS reach and relevance to SQL communities around the world. The VCs are a key vehicle for this expansion. Amy embraced this idea and organized the VC to engage volunteers in Europe & Australia and provide content that could reach SQL professionals in those regions. A second key strategy for PASS is expanding into the data analytics space. Again Amy rose to the occasion helping to shape the program for our first Business Analytics Conference and leveraging the BI VC to promote the event. By all measures I think Amy is prepared to serve on the Board and contribute in a positive way.

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  • Erfolgreich sein durch Reference Selling

    - by A&C Redaktion
    Referenzen sind eine hervorragende Möglichkeit, die Zuverlässigkeit von Partner-Lösungen auf Basis von Oracle Technologien darzustellen, denn sie sind ein Spiegelbild zufriedener Kunden. Sie dienen als Best Practices und beeinflussen damit positiv die Kaufentscheidung neuer Kunden. Iris Musiol, Customer Reference Manager DACH, erklärt das Oracle Referenzprogramm für Partner sowie deren Vorteile, Inhalte und Voraussetzungen.

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  • New Upgrade Technical Reference for SQL Server 2008 R2

    - by Greg Low
    Hi Folks, A year or two back, I was involved in a project with my colleagues from SolidQ (led by Ron Talmage) to construct an Upgrade Technical Reference for SQL Server 2008. It seemed to be well received. We've updated it now to SQL Server 2008 R2 and it's just been published. You'll find it on this web site: http://www.microsoft.com/sqlserver/en/us/product-info/why-upgrade.aspx You'll need to click on the Upgrade Guide link towards the middle of the RHS under the "Why Upgrade" whitepaper. Enjoy!...(read more)

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  • Add Reference with Search!

    - by vga
    Adds a "Search" textbox to the lovely "Add Reference" dialog allowing you to quickly find the assemblies you're looking for. Search for references, save time!  Go give it a try!

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  • Le PC demeure la plateforme de référence pour les développeurs, seulement 30 % développent des applications mobiles

    Le PC demeure la plateforme de référence pour les développeurs seulement 30 % développent des applications mobilesQue ce soit Gartner ou encore IDC, les cabinets spécialisés dans l'analyse de l'univers de l'IT ont mainte fois prédis que l'ère PC était révolue. Pour ce bon vieux PC, la messe aurait déjà été dite. Sauf que, concrètement ce ne soit pas toujours le cas. Dans le but d'observer l'évolution de l'écosystème du développement logiciel, une récente étude a été menée par SD Times auprès de...

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  • returning a heap block by reference in c++

    - by basicR
    I was trying to brush up my c++ skills. I got 2 functions: concat_HeapVal() returns the output heap variable by value concat_HeapRef() returns the output heap variable by reference When main() runs it will be on stack,s1 and s2 will be on stack, I pass the value by ref only and in each of the below functions, I create a variable on heap and concat them. When concat_HeapVal() is called it returns me the correct output. When concat_HeapRef() is called it returns me some memory address (wrong output). Why? I use new operator in both the functions. Hence it allocates on heap. So when I return by reference, heap will still be VALID even when my main() stack memory goes out of scope. So it's left to OS to cleanup the memory. Right? string& concat_HeapRef(const string& s1, const string& s2) { string *temp = new string(); temp->append(s1); temp->append(s2); return *temp; } string* concat_HeapVal(const string& s1, const string& s2) { string *temp = new string(); temp->append(s1); temp->append(s2); return temp; } int main() { string s1,s2; string heapOPRef; string *heapOPVal; cout<<"String Conact Experimentations\n"; cout<<"Enter s-1 : "; cin>>s1; cout<<"Enter s-2 : "; cin>>s2; heapOPRef = concat_HeapRef(s1,s2); heapOPVal = concat_HeapVal(s1,s2); cout<<heapOPRef<<" "<<heapOPVal<<" "<<endl; return -9; }

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  • How can arguments to variadic functions be passed by reference in PHP?

    - by outis
    Assuming it's possible, how would one pass arguments by reference to a variadic function without generating a warning in PHP? We can no longer use the '&' operator in a function call, otherwise I'd accept that (even though it would be error prone, should a coder forget it). What inspired this is are old MySQLi wrapper classes that I unearthed (these days, I'd just use PDO). The only difference between the wrappers and the MySQLi classes is the wrappers throw exceptions rather than returning FALSE. class DBException extends RuntimeException {} ... class MySQLi_throwing extends mysqli { ... function prepare($query) { $stmt = parent::prepare($query); if (!$stmt) { throw new DBException($this->error, $this->errno); } return new MySQLi_stmt_throwing($this, $query, $stmt); } } // I don't remember why I switched from extension to composition, but // it shouldn't matter for this question. class MySQLi_stmt_throwing /* extends MySQLi_stmt */ { protected $_link, $_query, $_delegate; public function __construct($link, $query, $prepared) { //parent::__construct($link, $query); $this->_link = $link; $this->_query = $query; $this->_delegate = $prepared; } function bind_param($name, &$var) { return $this->_delegate->bind_param($name, $var); } function __call($name, $args) { //$rslt = call_user_func_array(array($this, 'parent::' . $name), $args); $rslt = call_user_func_array(array($this->_delegate, $name), $args); if (False === $rslt) { throw new DBException($this->_link->error, $this->errno); } return $rslt; } } The difficulty lies in calling methods such as bind_result on the wrapper. Constant-arity functions (e.g. bind_param) can be explicitly defined, allowing for pass-by-reference. bind_result, however, needs all arguments to be pass-by-reference. If you call bind_result on an instance of MySQLi_stmt_throwing as-is, the arguments are passed by value and the binding won't take. try { $id = Null; $stmt = $db->prepare('SELECT id FROM tbl WHERE ...'); $stmt->execute() $stmt->bind_result($id); // $id is still null at this point ... } catch (DBException $exc) { ... } Since the above classes are no longer in use, this question is merely a matter of curiosity. Alternate approaches to the wrapper classes are not relevant. Defining a method with a bunch of arguments taking Null default values is not correct (what if you define 20 arguments, but the function is called with 21?). Answers don't even need to be written in terms of MySQL_stmt_throwing; it exists simply to provide a concrete example.

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  • ASP.net page gets error on import statement, but I do have the reference in place?

    - by Greg
    Hi, Any ideas why I am getting the below error in my MVC2 project, even through in the project itself I definitely have a reference to "system.Web.Entity"? Compiler Error Message: CS0234: The type or namespace name 'Entity' does not exist in the namespace 'System.Data' (are you missing an assembly reference?) Source Error: Line 1: <%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage<List<Node>>" %> Line 2: <%@ Import Namespace="TopologyDAL" %> Line 3: <%@ Import Namespace="System.Data.Entity" %> thanks

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  • Should the argument be passed by reference in this .net example?

    - by Hamish Grubijan
    I have used Java, C++, .Net. (in that order). When asked about by-value vs. by-ref on interviews, I have always done well on that question ... perhaps because nobody went in-depth on it. Now I know that I do not see the whole picture. I was looking at this section of code written by someone else: XmlDocument doc = new XmlDocument(); AppendX(doc); // Real name of the function is different AppendY(doc); // ditto When I saw this code, I thought: wait a minute, should not I use a ref in front of doc variable (and modify AppendX/Y accordingly? it works as written, but made me question whether I actually understand the ref keyword in C#. As I thought about this more, I recalled early Java days (college intro language). A friend of mine looked at some code I have written and he had a mental block - he kept asking me which things are passed in by reference and when by value. My ignorant response was something like: Dude, there is only one kind of arg passing in Java and I forgot which one it is :). Chill, do not over-think and just code. Java still does not have a ref does it? Yet, Java hackers seem to be productive. Anyhow, coding in C++ exposed me to this whole by reference business, and now I am confused. Should ref be used in the example above? I am guessing that when ref is applied to value types: primitives, enums, structures (is there anything else in this list?) it makes a big difference. And ... when applied to objects it does not because it is all by reference. If things were so simple, then why would not the compiler restrict the usage of ref keyword to a subset of types. When it comes to objects, does ref serve as a comment sort of? Well, I do remember that there can be problems with null and ref is also useful for initializing multiple elements within a method (since you cannot return multiple things with the same easy as you would do in Python). Thanks.

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