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  • knowing all available entity types

    - by plofplof
    I'm making a game where at some point the game will create enemies of random types. Each type of enemy available is defined on its own class derived from an enemy superclass. To do this, obviously the different types of enemies should be known. This is what I have thought of: Just make a list manually. Very simple to do, but I don't like it because I'll be adding more enemy types over time, so any time I add a new class I have to remember to update this (same if I remove an enemy). I would like some kind of auto-updating list. A completely component based system. There are no different classes for each enemy, but definitions of enemies in some file where all enemy types can be found. I really don't need that level of complexity for my game. I'm still using a component based model to some degree, but each Enemy type gets defined on its own class. Java Annotation processing. Give each enemy subclass an annotation like @EnemyType("whatever"), then code an annotation processor that writes in a file all available enemy types. Any time a new class is added the file gets updated after compilation.This gives me a feeling of failure even if its a good solution, it's very dependant on Java, so it means I cant think of a general design good for any kind of language. Also I think that this would be too much work for something so simple. I would like to see comments on these ideas and other possible solutions Thanks

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  • How to wait for the user to select one of the datagridview rows?

    - by Jhon
    I have a datagridview populated with some Names, I want to perform a check of all the Name in another database with the Names in datagridview and add the Surnames to the adjacent cell when a match is found, this I am achieving by string compare method. My Problem is that due to typing inconsistencies & at times with two people having same names some of the names are not being adjudged properly. What I want is to give user the choice to either choose one of the names present in Datagridview which they consider is best match or enter both First Name & Surname in a new row. To achieve this I want the program to wait until user has clicked on one of the rows in the datagridview. Is there a way to wait to this effect? Thanks Jhon

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  • How to diagnose Ubuntu CPU spikes / IO wait?

    - by Jeff Welling
    I'm using Ubuntu and every couple minutes it goes unresponsive for a half second to a full second, which isn't normally a problem but makes trying to code extremely frustrating when your trying to hit backspace or navigate the code and nothing is happening. The problem is, the freezes are so brief that top doesn't have time to show me what is spiking the CPU (assuming something is, but I don't know what else could cause this). Does anyone know how to troubleshoot this performance issue? Edit: I've tried login in with Gnome Classic (No Effects) instead of Unity but it still freezes up every once in awhile. Edit: The CPU graph doesn't seem to be showing any actual spikes so it seems you were right and my original diagnosis of CPU spikes being the problem was incorrect, I now suspect IO wait. I don't recall this happening for the brief few weeks I had Windows 7 Starter running on it though, which leads me to believe it isn't (just?) the hardware.. is there anything I can tweak to improve this? I'm using an Acer Aspire One D257, with Ubuntu 11.10. Edit: Output of dmesg is at http://paste.ubuntu.com/1060054/ and kern.log is at http://paste.ubuntu.com/1060055/

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  • Handling commands or events that wait for an action to be completed afterwards

    - by virulent
    Say you have two events: Action1 and Action2. When you receive Action1, you want to store some arbitrary data to be used the next time Action2 rolls around. Optimally, Action1 is normally a command however it can also be other events. The idea is still the same. The current way I am implementing this is by storing state and then simply checking when Action2 is called if that specific state is there. This is obviously a bit messy and leads to a lot of redundant code. Here is an example of how I am doing that, in pseudocode form (and broken down quite a bit, obviously): void onAction1(event) { Player = event.getPlayer() Player.addState("my_action_to_do") } void onAction2(event) { Player = event.getPlayer() if not Player.hasState("my_action_to_do") { return } // Do something } When doing this for a lot of other actions it gets somewhat ugly and I wanted to know if there is something I can do to improve upon it. I was thinking of something like this, which wouldn't require passing data around, but is this also not the right direction? void onAction1(event) { Player = event.getPlayer() Player.onAction2(new Runnable() { public void run() { // Do something } }) } If one wanted to take it even further, could you not simply do this? void onPlayerEnter(event) { // When they join the server Player = event.getPlayer() Player.onAction1(new Runnable() { public void run() { // Now wait for action 2 Player.onAction2(new Runnable() { // Do something }) } }, true) // TRUE would be to repeat the event, // not remove it after it is called. } Any input would be wonderful.

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  • High Lock Wait ratio in MySQL

    - by FunkyChicken
    on my site I log every pageview (date,ip,referrer,page,etc) in a simple mysql table. This table gets very little selects (3 per minute), but a lot of inserts. (about 100 per second) Today I changed this table from an InnoDB table to a MEMORY table, this made sense to me to prevent unnecessary hard disk IO. I also prune this table once per minute, to make sure it never get's too big. -- Performance wise, things are running fine. But I noticed that while running tuning-primer, that my Current Lock Wait ratio is quite high. Current Lock Wait ratio = 1 : 561 My question: Should I worry about this Lock Wait Ratio? And is there something I can change in my my.cnf to improve things so that the lock wait ratio isn't so high?

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  • Smart way to find the corresponding nullable type?

    - by Marc Wittke
    How could I avoid this dictionary (or create it dynamically)? Dictionary<Type,Type> CorrespondingNullableType = new Dictionary<Type, Type> { {typeof(bool), typeof(bool?)}, {typeof(byte), typeof(byte?)}, {typeof(sbyte), typeof(sbyte?)}, {typeof(char), typeof(char?)}, {typeof(decimal), typeof(decimal?)}, {typeof(double), typeof(double?)}, {typeof(float), typeof(float?)}, {typeof(int), typeof(int?)}, {typeof(uint), typeof(uint?)}, {typeof(long), typeof(long?)}, {typeof(ulong), typeof(ulong?)}, {typeof(short), typeof(short?)}, {typeof(ushort), typeof(ushort?)}, {typeof(Guid), typeof(Guid?)}, };

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  • Consing lists with user-defined type in Haskell

    - by user1319603
    I have this type I defined myself: data Item = Book String String String Int -- Title, Author, Year, Qty | Movie String String String Int -- Title, Director, Year, Qty | CD String String String Int deriving Show -- Title, Artist, Year, Qty I've created an empty list all_Items = [] With the following function I am trying to insert a new book of type Item (Book) into the all_Items addBook all_Items = do putStrLn "Enter the title of the book" tit <- getLine putStrLn "Enter the author of the book" aut <- getLine putStrLn "Enter the year this book was published" yr <- getLine putStrLn "Enter quantity of copies for this item in the inventory" qty <- getLine Book tit aut yr (read qty::Int):all_Items return(all_Items) I however am receiving this error: Couldn't match expected type `IO a0' with actual type `[a1]' The error points to the line where I am using the consing operator to add the new book to the list. I can gather that it is a type error but I can't figure out what it is that I am doing wrong and how to fix it. Thanks in Advance!

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  • Java: over-typed structures? To have many types in Object[]?

    - by HH
    Term over-type structure = a data structure that accepts different types, can be primitive or user-defined. I think ruby supports many types in structures such as tables. I tried a table with types 'String', 'char' and 'File' in Java but errs. How can I have over-typed structure in Java? How to show types in declaration? What about in initilization? Suppose a structure: INDEX VAR FILETYPE //0 -> file FILE //1 -> lineMap SizeSequence //2 -> type char //3 -> binary boolean //4 -> name String //5 -> path String Code import java.io.*; import java.util.*; public class Object { public static void print(char a) { System.out.println(a); } public static void print(String s) { System.out.println(s); } public static void main(String[] args) { Object[] d = new Object[6]; d[0] = new File("."); d[2] = 'T'; d[4] = "."; print(d[2]); print(d[4]); } } Errors Object.java:18: incompatible types found : java.io.File required: Object d[0] = new File("."); ^ Object.java:19: incompatible types found : char required: Object d[2] = 'T'; ^

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  • SQL SERVER – 2012 – List All The Column With Specific Data Types in Database

    - by pinaldave
    5 years ago I wrote script SQL SERVER – 2005 – List All The Column With Specific Data Types, when I read it again, it is very much relevant and I liked it. This is one of the script which every developer would like to keep it handy. I have upgraded the script bit more. I have included few additional information which I believe I should have added from the beginning. It is difficult to visualize the final script when we are writing it first time. I use every script which I write on this blog, the matter of the fact, I write only those scripts here which I was using at that time. It is quite possible that as time passes by my needs are changing and I change my script. Here is the updated script of this subject. If there are any user data types, it will list the same as well. SELECT s.name AS 'schema', ts.name AS TableName, c.name AS column_name, c.column_id, SCHEMA_NAME(t.schema_id) AS DatatypeSchema, t.name AS Datatypename ,t.is_user_defined, t.is_assembly_type ,c.is_nullable, c.max_length, c.PRECISION, c.scale FROM sys.columns AS c INNER JOIN sys.types AS t ON c.user_type_id=t.user_type_id INNER JOIN sys.tables ts ON ts.OBJECT_ID = c.OBJECT_ID INNER JOIN sys.schemas s ON s.schema_id = t.schema_id ORDER BY s.name, ts.name, c.column_id I would be very interested to see your script which lists all the columns of the database with data types. If I am missing something in my script, I will modify it based on your comment. This way this page will be a good bookmark for the future for all of us. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology

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  • Getting Started with TypeScript – Classes, Static Types and Interfaces

    - by dwahlin
    I had the opportunity to speak on different JavaScript topics at DevConnections in Las Vegas this fall and heard a lot of interesting comments about JavaScript as I talked with people. The most frequent comment I heard from people was, “I guess it’s time to start learning JavaScript”. Yep – if you don’t already know JavaScript then it’s time to learn it. As HTML5 becomes more and more popular the amount of JavaScript code written will definitely increase. After all, many of the HTML5 features available in browsers have little to do with “tags” and more to do with JavaScript (web workers, web sockets, canvas, local storage, etc.). As the amount of JavaScript code being used in applications increases, it’s more important than ever to structure the code in a way that’s maintainable and easy to debug. While JavaScript patterns can certainly be used (check out my previous posts on the subject or my course on Pluralsight.com), several alternatives have come onto the scene such as CoffeeScript, Dart and TypeScript. In this post I’ll describe some of the features TypeScript offers and the benefits that they can potentially offer enterprise-scale JavaScript applications. It’s important to note that while TypeScript has several great features, it’s definitely not for everyone or every project especially given how new it is. The goal of this post isn’t to convince you to use TypeScript instead of standard JavaScript….I’m a big fan of JavaScript. Instead, I’ll present several TypeScript features and let you make the decision as to whether TypeScript is a good fit for your applications. TypeScript Overview Here’s the official definition of TypeScript from the http://typescriptlang.org site: “TypeScript is a language for application-scale JavaScript development. TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. Any browser. Any host. Any OS. Open Source.” TypeScript was created by Anders Hejlsberg (the creator of the C# language) and his team at Microsoft. To sum it up, TypeScript is a new language that can be compiled to JavaScript much like alternatives such as CoffeeScript or Dart. It isn’t a stand-alone language that’s completely separate from JavaScript’s roots though. It’s a superset of JavaScript which means that standard JavaScript code can be placed in a TypeScript file (a file with a .ts extension) and used directly. That’s a very important point/feature of the language since it means you can use existing code and frameworks with TypeScript without having to do major code conversions to make it all work. Once a TypeScript file is saved it can be compiled to JavaScript using TypeScript’s tsc.exe compiler tool or by using a variety of editors/tools. TypeScript offers several key features. First, it provides built-in type support meaning that you define variables and function parameters as being “string”, “number”, “bool”, and more to avoid incorrect types being assigned to variables or passed to functions. Second, TypeScript provides a way to write modular code by directly supporting class and module definitions and it even provides support for custom interfaces that can be used to drive consistency. Finally, TypeScript integrates with several different tools such as Visual Studio, Sublime Text, Emacs, and Vi to provide syntax highlighting, code help, build support, and more depending on the editor. Find out more about editor support at http://www.typescriptlang.org/#Download. TypeScript can also be used with existing JavaScript frameworks such as Node.js, jQuery, and others and even catch type issues and provide enhanced code help. Special “declaration” files that have a d.ts extension are available for Node.js, jQuery, and other libraries out-of-the-box. Visit http://typescript.codeplex.com/SourceControl/changeset/view/fe3bc0bfce1f#samples%2fjquery%2fjquery.d.ts for an example of a jQuery TypeScript declaration file that can be used with tools such as Visual Studio 2012 to provide additional code help and ensure that a string isn’t passed to a parameter that expects a number. Although declaration files certainly aren’t required, TypeScript’s support for declaration files makes it easier to catch issues upfront while working with existing libraries such as jQuery. In the future I expect TypeScript declaration files will be released for different HTML5 APIs such as canvas, local storage, and others as well as some of the more popular JavaScript libraries and frameworks. Getting Started with TypeScript To get started learning TypeScript visit the TypeScript Playground available at http://www.typescriptlang.org. Using the playground editor you can experiment with TypeScript code, get code help as you type, and see the JavaScript that TypeScript generates once it’s compiled. Here’s an example of the TypeScript playground in action:   One of the first things that may stand out to you about the code shown above is that classes can be defined in TypeScript. This makes it easy to group related variables and functions into a container which helps tremendously with re-use and maintainability especially in enterprise-scale JavaScript applications. While you can certainly simulate classes using JavaScript patterns (note that ECMAScript 6 will support classes directly), TypeScript makes it quite easy especially if you come from an object-oriented programming background. An example of the Greeter class shown in the TypeScript Playground is shown next: class Greeter { greeting: string; constructor (message: string) { this.greeting = message; } greet() { return "Hello, " + this.greeting; } } Looking through the code you’ll notice that static types can be defined on variables and parameters such as greeting: string, that constructors can be defined, and that functions can be defined such as greet(). The ability to define static types is a key feature of TypeScript (and where its name comes from) that can help identify bugs upfront before even running the code. Many types are supported including primitive types like string, number, bool, undefined, and null as well as object literals and more complex types such as HTMLInputElement (for an <input> tag). Custom types can be defined as well. The JavaScript output by compiling the TypeScript Greeter class (using an editor like Visual Studio, Sublime Text, or the tsc.exe compiler) is shown next: var Greeter = (function () { function Greeter(message) { this.greeting = message; } Greeter.prototype.greet = function () { return "Hello, " + this.greeting; }; return Greeter; })(); Notice that the code is using JavaScript prototyping and closures to simulate a Greeter class in JavaScript. The body of the code is wrapped with a self-invoking function to take the variables and functions out of the global JavaScript scope. This is important feature that helps avoid naming collisions between variables and functions. In cases where you’d like to wrap a class in a naming container (similar to a namespace in C# or a package in Java) you can use TypeScript’s module keyword. The following code shows an example of wrapping an AcmeCorp module around the Greeter class. In order to create a new instance of Greeter the module name must now be used. This can help avoid naming collisions that may occur with the Greeter class.   module AcmeCorp { export class Greeter { greeting: string; constructor (message: string) { this.greeting = message; } greet() { return "Hello, " + this.greeting; } } } var greeter = new AcmeCorp.Greeter("world"); In addition to being able to define custom classes and modules in TypeScript, you can also take advantage of inheritance by using TypeScript’s extends keyword. The following code shows an example of using inheritance to define two report objects:   class Report { name: string; constructor (name: string) { this.name = name; } print() { alert("Report: " + this.name); } } class FinanceReport extends Report { constructor (name: string) { super(name); } print() { alert("Finance Report: " + this.name); } getLineItems() { alert("5 line items"); } } var report = new FinanceReport("Month's Sales"); report.print(); report.getLineItems();   In this example a base Report class is defined that has a variable (name), a constructor that accepts a name parameter of type string, and a function named print(). The FinanceReport class inherits from Report by using TypeScript’s extends keyword. As a result, it automatically has access to the print() function in the base class. In this example the FinanceReport overrides the base class’s print() method and adds its own. The FinanceReport class also forwards the name value it receives in the constructor to the base class using the super() call. TypeScript also supports the creation of custom interfaces when you need to provide consistency across a set of objects. The following code shows an example of an interface named Thing (from the TypeScript samples) and a class named Plane that implements the interface to drive consistency across the app. Notice that the Plane class includes intersect and normal as a result of implementing the interface.   interface Thing { intersect: (ray: Ray) => Intersection; normal: (pos: Vector) => Vector; surface: Surface; } class Plane implements Thing { normal: (pos: Vector) =>Vector; intersect: (ray: Ray) =>Intersection; constructor (norm: Vector, offset: number, public surface: Surface) { this.normal = function (pos: Vector) { return norm; } this.intersect = function (ray: Ray): Intersection { var denom = Vector.dot(norm, ray.dir); if (denom > 0) { return null; } else { var dist = (Vector.dot(norm, ray.start) + offset) / (-denom); return { thing: this, ray: ray, dist: dist }; } } } }   At first glance it doesn’t appear that the surface member is implemented in Plane but it’s actually included automatically due to the public surface: Surface parameter in the constructor. Adding public varName: Type to a constructor automatically adds a typed variable into the class without having to explicitly write the code as with normal and intersect. TypeScript has additional language features but defining static types and creating classes, modules, and interfaces are some of the key features it offers. So is TypeScript right for you and your applications? That’s a not a question that I or anyone else can answer for you. You’ll need to give it a spin to see what you think. In future posts I’ll discuss additional details about TypeScript and how it can be used with enterprise-scale JavaScript applications. In the meantime, I’m in the process of working with John Papa on a new Typescript course for Pluralsight that we hope to have out in December of 2012.

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  • Thread.sleep vs Monitor.Wait vs RegisteredWaitHandle?

    - by Royi Namir
    (the following items has different goals , but im interesting knowing how they "PAUSEd") questions Thread.sleep - Does it impact performance on a system ?does it tie up a thread with its wait ? what about Monitor.Wait ? what is the difference in the way they "wait"? do they tie up a thread with their wait ? what aboutRegisteredWaitHandle ? This method accepts a delegate that is executed when a wait handle is signaled. While it’s waiting, it doesn’t tie up a thread. so some thread are paused and can be woken by a delegate , while others just wait ? spin ? can someone please make things clearer ? edit http://www.albahari.com/threading/part2.aspx

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  • Lot of time spent with following waits 'SQL*Net message from client' and 'wait for unread message on

    - by Shravan
    My application that wraps around Oracle Data pump's executables IMPDP and EXPDP takes random amounts of time for the same work. On further investigation, I see it waiting for again random amounts of time with the event 'wait for unread message on broadcast channel'. This makes the application take anytime b/w 10 minutes to over an hour for the same work. I fail to understand if this has something to do with the way my application uses these executables, or it has got something to do with Load on my server or something totally alien to me.

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  • JPA - insert and retrieve clob and blob types

    - by pachunoori.vinay.kumar(at)oracle.com
    This article describes about the JPA feature for handling clob and blob data types.You will learn the following in this article. @Lob annotation Client code to insert and retrieve the clob/blob types End to End ADFaces application to retrieve the image from database table and display it in web page. Use Case Description Persisting and reading the image from database using JPA clob/blob type. @Lob annotation By default, TopLink JPA assumes that all persistent data can be represented as typical database data types. Use the @Lob annotation with a basic mapping to specify that a persistent property or field should be persisted as a large object to a database-supported large object type. A Lob may be either a binary or character type. TopLink JPA infers the Lob type from the type of the persistent field or property. For string and character-based types, the default is Clob. In all other cases, the default is Blob. Example Below code shows how to use this annotation to specify that persistent field picture should be persisted as a Blob. public class Person implements Serializable {    @Id    @Column(nullable = false, length = 20)    private String name;    @Column(nullable = false)    @Lob    private byte[] picture;    @Column(nullable = false, length = 20) } Client code to insert and retrieve the clob/blob types Reading a image file and inserting to Database table Below client code will read the image from a file and persist to Person table in database.                       Person p=new Person();                      p.setName("Tom");                      p.setSex("male");                      p.setPicture(writtingImage("Image location"));// - c:\images\test.jpg                       sessionEJB.persistPerson(p); //Retrieving the image from Database table and writing to a file                       List<Person> plist=sessionEJB.getPersonFindAll();//                      Person person=(Person)plist.get(0);//get a person object                      retrieveImage(person.getPicture());   //get picture retrieved from Table //Private method to create byte[] from image file  private static byte[] writtingImage(String fileLocation) {      System.out.println("file lication is"+fileLocation);     IOManager manager=new IOManager();        try {           return manager.getBytesFromFile(fileLocation);                    } catch (IOException e) {        }        return null;    } //Private method to read byte[] from database and write to a image file    private static void retrieveImage(byte[] b) {    IOManager manager=new IOManager();        try {            manager.putBytesInFile("c:\\webtest.jpg",b);        } catch (IOException e) {        }    } End to End ADFaces application to retrieve the image from database table and display it in web page. Please find the application in this link. Following are the j2ee components used in the sample application. ADFFaces(jspx page) HttpServlet Class - Will make a call to EJB and retrieve the person object from person table.Read the byte[] and write to response using Outputstream. SessionEJBBean - This is a session facade to make a local call to JPA entities JPA Entity(Person.java) - Person java class with setter and getter method annotated with @Lob representing the clob/blob types for picture field.

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  • Check your Embed Interop Types flag when doing Visual Studio extensibility work

    - by Daniel Cazzulino
    In case you didn’t notice, VS2010 adds a new property to assembly references in the properties window: Embed Interop Types: This property was introduced as a way to overcome the pain of deploying Primary Interop Assemblies. Read that blog post, it will help understand why you DON’T need it when doing VS extensibility (VSX) work. It's generally advisable when doing VSX development NOT to use Embed Interop Types, which is a feature intended mostly for office PIA scenarios where the PIA assemblies are HUGE and had to be shipped with your app. This is NEVER the case with VSX authoring. All interop assemblies you reference (EnvDTE, VS.Shell, etc.) are ALWAYS already there in the users' machine, and you NEVER need to distribute them. So embedding those types only increases your assembly size without a single benefit to you (the extension developer/author).... Read full article

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  • Is nesting types considered bad practice?

    - by Rob Z
    As noted by the title, is nesting types (e.g. enumerated types or structures in a class) considered bad practice or not? When you run Code Analysis in Visual Studio it returns the following message which implies it is: Warning 34 CA1034 : Microsoft.Design : Do not nest type 'ClassName.StructueName'. Alternatively, change its accessibility so that it is not externally visible. However, when I follow the recommendation of the Code Analysis I find that there tend to be a lot of structures and enumerated types floating around in the application that might only apply to a single class or would only be used with that class. As such, would it be appropriate to nest the type sin that case, or is there a better way of doing it?

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  • Fundamental types

    - by smerlin
    I always thought the following types are "fundamental types", so i thought my anwser to this question would be correct, but surprisingly it got downvoted... Searching the web, i found this. So, IBM says aswell those types are fundamental types.. Well how do you interpret the Standard, are following types (and similar types), "fundamental types" according to the c++ standard ? unsigned int signed char long double long long long long int unsigned long long int

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  • C# Inhieriting DataContract Derived Types

    - by dsjohnston
    I've given a fair read through msdn:datacontracts and I cannot find a out why the following does not work. So what is wrong here? Why isn't ExtendedCanadianAddress recognized by the datacontract serializer? Type 'XYZ.ExtendedCanadianAddress' with data contract name 'CanadianAddress:http://tempuri.org/Common/Types' is not expected. Add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer. Given: namespace ABC { [KnownType(typeof(Address))] public abstract class Z { //stuff //method that adds all types() in namespace to self } [KnownType(typeof(CanadianAddress))] [DataContact(Name = "Address", Namespace = "http://tempuri.org/Types")] public class Address : Z {} [DataContract(Name = "CanadianAddress", Namespace = "http://tempuri.org/Types")] public class CanadianAddress : Address {} } namespace XYZ { [KnownType(typeof(ExtendedCanadianAddress)) [DataContact(Name = "Address", Namespace = "http://tempuri.org/Types")] public class ExtendedAddress : Address { //this serializes just fine } [DataContact(Name = "CanadianAddress", Namespace = "http://tempuri.org/Types")] public class ExtendedCanadianAddress : CanadianAddress { //will NOT serialize } }

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  • How does the CLR (.NET) internally allocate and pass around custom value types (structs)?

    - by stakx
    Question: Do all CLR value types, including user-defined structs, live on the evaluation stack exclusively, meaning that they will never need to be reclaimed by the garbage-collector, or are there cases where they are garbage-collected? Background: I have previously asked a question on SO about the impact that a fluent interface has on the runtime performance of a .NET application. I was particuarly worried that creating a large number of very short-lived temporary objects would negatively affect runtime performance through more frequent garbage-collection. Now it has occured to me that if I declared those temporary objects' types as struct (ie. as user-defined value types) instead of class, the garbage collector might not be involved at all if it turns out that all value types live exclusively on the evaluation stack. What I've found out so far: I did a brief experiment to see what the differences are in the CIL generated for user-defined value types and reference types. This is my C# code: struct SomeValueType { public int X; } class SomeReferenceType { public int X; } . . static void TryValueType(SomeValueType vt) { ... } static void TryReferenceType(SomeReferenceType rt) { ... } . . var vt = new SomeValueType { X = 1 }; var rt = new SomeReferenceType { X = 2 }; TryValueType(vt); TryReferenceType(rt); And this is the CIL generated for the last four lines of code: .locals init ( [0] valuetype SomeValueType vt, [1] class SomeReferenceType rt, [2] valuetype SomeValueType <>g__initLocal0, // [3] class SomeReferenceType <>g__initLocal1, // why are these generated? [4] valuetype SomeValueType CS$0$0000 // ) L_0000: ldloca.s CS$0$0000 L_0002: initobj SomeValueType // no newobj required, instance already allocated L_0008: ldloc.s CS$0$0000 L_000a: stloc.2 L_000b: ldloca.s <>g__initLocal0 L_000d: ldc.i4.1 L_000e: stfld int32 SomeValueType::X L_0013: ldloc.2 L_0014: stloc.0 L_0015: newobj instance void SomeReferenceType::.ctor() L_001a: stloc.3 L_001b: ldloc.3 L_001c: ldc.i4.2 L_001d: stfld int32 SomeReferenceType::X L_0022: ldloc.3 L_0023: stloc.1 L_0024: ldloc.0 L_0025: call void Program::TryValueType(valuetype SomeValueType) L_002a: ldloc.1 L_002b: call void Program::TryReferenceType(class SomeReferenceType) What I cannot figure out from this code is this: Where are all those local variables mentioned in the .locals block allocated? How are they allocated? How are they freed? Why are so many anonymous local variables needed and copied to-and-fro only to initialize my two local variables rt and vt?

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  • Reverse-engineer SharePoint fields, content types and list instance—Part2

    - by ybbest
    Reverse-engineer SharePoint fields, content types and list instance—Part1 Reverse-engineer SharePoint fields, content types and list instance—Part2 In the part1 of this series, I demonstrated how to use VS2010 to Reverse-engineer SharePoint fields, content types and list instances. In the part 2 of this series, I will demonstrate how to do the same using CKS:Dev. CKS:Dev extends the Visual Studio 2010 SharePoint project system with advanced templates and tools. Using these extensions you will be able to find relevant information from your SharePoint environments without leaving Visual Studio. You will have greater productivity while developing SharePoint components and you will have greater deployment capabilities on your local SharePoint installation. You can download the complete solution here. 1. First, download and install appropriate CKS:Dev from CodePlex. If you are using SharePoint Foundation 2010 then download and install the SharePoint Foundation 2010 version If you are using SharePoint Server 2010 then download and install the SharePoint Server 2010 version 2. After installation, you need to restart your visual studio and create empty SharePoint. 3. Go to Viewà Server Explorer 4. Add SharePoint web application connection to the server explorer. 5. After add the connection, you can browse to see the contents for the Web Application. 6. Go to Site Columns à YBBEST (Custom Group of you own choice) and right-click the YBBEST Folder and Click Import Site Columns. 7. Go to ContentTypesà YBBEST (Custom Group of you own choice) and right-click the YBBEST Folder and Click Import Content Types. 8. After the import completes, you can find the fields and contentTypes in the SharePoint project below. Of course you need to do some modification to your current project to make it work. 9. Next, create list instances using list instance item template in Visual Studio 10. Finally, create lookup columns using the feature receivers and the final project will look like this. You can download the complete solution here.

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  • Ten - oh, wait, eleven - Eleven things you should know about the ASP.NET Fall 2012 Update

    - by Jon Galloway
    Today, just a little over two months after the big ASP.NET 4.5 / ASP.NET MVC 4 / ASP.NET Web API / Visual Studio 2012 / Web Matrix 2 release, the first preview of the ASP.NET Fall 2012 Update is out. Here's what you need to know: There are no new framework bits in this release - there's no change or update to ASP.NET Core, ASP.NET MVC or Web Forms features. This means that you can start using it without any updates to your server, upgrade concerns, etc. This update is really an update to the project templates and Visual Studio tooling, conceptually similar to the ASP.NET MVC 3 Tools Update. It's a relatively lightweight install. It's a 41MB download. I've installed it many times and usually takes 5-7 minutes; it's never required a reboot. It adds some new project templates to ASP.NET MVC: Facebook Application and Single Page Application templates. It adds a lot of cool enhancements to ASP.NET Web API. It adds some tooling that makes it easy to take advantage of features like SignalR, Friendly URLs, and Windows Azure Authentication. Most of the new features are installed via NuGet packages. Since ASP.NET is open source, nightly NuGet packages are available, and the roadmap is published, most of this has really been publicly available for a while. The official name of this drop is the ASP.NET Fall 2012 Update BUILD Prerelease. Please do not attempt to say that ten times fast. While the EULA doesn't prohibit it, it WILL legally change your first name to Scott. As with all new releases, you can find out everything you need to know about the Fall Update at http://asp.net/vnext (especially the release notes!) I'm going to be showing all of this off, assisted by special guest code monkey Scott Hanselman, this Friday at BUILD: Bleeding edge ASP.NET: See what is next for MVC, Web API, SignalR and more… (and I've heard it will be livestreamed). Let's look at some of those things in more detail. No new bits ASP.NET 4.5, MVC 4 and Web API have a lot of great core features. I see the goal of this update release as making it easier to put those features to use to solve some useful scenarios by taking advantage of NuGet packages and template code. If you create a new ASP.NET MVC application using one of the new templates, you'll see that it's using the ASP.NET MVC 4 RTM NuGet package (4.0.20710.0): This means you can install and use the Fall Update without any impact on your existing projects and no worries about upgrading or compatibility. New Facebook Application Template ASP.NET MVC 4 (and ASP.NET 4.5 Web Forms) included the ability to authenticate your users via OAuth and OpenID, so you could let users log in to your site using a Facebook account. One of the new changes in the Fall Update is a new template that makes it really easy to create full Facebook applications. You could create Facebook application in ASP.NET already, you'd just need to go through a few steps: Search around to find a good Facebook NuGet package, like the Facebook C# SDK (written by my friend Nathan Totten and some other Facebook SDK brainiacs). Read the Facebook developer documentation to figure out how to authenticate and integrate with them. Write some code, debug it and repeat until you got something working. Get started with the application you'd originally wanted to write. What this template does for you: eliminate steps 1-3. Erik Porter, Nathan and some other experts built out the Facebook Application template so it automatically pulls in and configures the Facebook NuGet package and makes it really easy to take advantage of it in an ASP.NET MVC application. One great example is the the way you access a Facebook user's information. Take a look at the following code in a File / New / MVC / Facebook Application site. First, the Home Controller Index action: [FacebookAuthorize(Permissions = "email")] public ActionResult Index(MyAppUser user, FacebookObjectList<MyAppUserFriend> userFriends) { ViewBag.Message = "Modify this template to jump-start your Facebook application using ASP.NET MVC."; ViewBag.User = user; ViewBag.Friends = userFriends.Take(5); return View(); } First, notice that there's a FacebookAuthorize attribute which requires the user is authenticated via Facebook and requires permissions to access their e-mail address. It binds to two things: a custom MyAppUser object and a list of friends. Let's look at the MyAppUser code: using Microsoft.AspNet.Mvc.Facebook.Attributes; using Microsoft.AspNet.Mvc.Facebook.Models; // Add any fields you want to be saved for each user and specify the field name in the JSON coming back from Facebook // https://developers.facebook.com/docs/reference/api/user/ namespace MvcApplication3.Models { public class MyAppUser : FacebookUser { public string Name { get; set; } [FacebookField(FieldName = "picture", JsonField = "picture.data.url")] public string PictureUrl { get; set; } public string Email { get; set; } } } You can add in other custom fields if you want, but you can also just bind to a FacebookUser and it will automatically pull in the available fields. You can even just bind directly to a FacebookUser and check for what's available in debug mode, which makes it really easy to explore. For more information and some walkthroughs on creating Facebook applications, see: Deploying your first Facebook App on Azure using ASP.NET MVC Facebook Template (Yao Huang Lin) Facebook Application Template Tutorial (Erik Porter) Single Page Application template Early releases of ASP.NET MVC 4 included a Single Page Application template, but it was removed for the official release. There was a lot of interest in it, but it was kind of complex, as it handled features for things like data management. The new Single Page Application template that ships with the Fall Update is more lightweight. It uses Knockout.js on the client and ASP.NET Web API on the server, and it includes a sample application that shows how they all work together. I think the real benefit of this application is that it shows a good pattern for using ASP.NET Web API and Knockout.js. For instance, it's easy to end up with a mess of JavaScript when you're building out a client-side application. This template uses three separate JavaScript files (delivered via a Bundle, of course): todoList.js - this is where the main client-side logic lives todoList.dataAccess.js - this defines how the client-side application interacts with the back-end services todoList.bindings.js - this is where you set up events and overrides for the Knockout bindings - for instance, hooking up jQuery validation and defining some client-side events This is a fun one to play with, because you can just create a new Single Page Application and hit F5. Quick, easy install (with one gotcha) One of the cool engineering changes for this release is a big update to the installer to make it more lightweight and efficient. I've been running nightly builds of this for a few weeks to prep for my BUILD demos, and the install has been really quick and easy to use. The install takes about 5 minutes, has never required a reboot for me, and the uninstall is just as simple. There's one gotcha, though. In this preview release, you may hit an issue that will require you to uninstall and re-install the NuGet VSIX package. The problem comes up when you create a new MVC application and see this dialog: The solution, as explained in the release notes, is to uninstall and re-install the NuGet VSIX package: Start Visual Studio 2012 as an Administrator Go to Tools->Extensions and Updates and uninstall NuGet. Close Visual Studio Navigate to the ASP.NET Fall 2012 Update installation folder: For Visual Studio 2012: Program Files\Microsoft ASP.NET\ASP.NET Web Stack\Visual Studio 2012 For Visual Studio 2012 Express for Web: Program Files\Microsoft ASP.NET\ASP.NET Web Stack\Visual Studio Express 2012 for Web Double click on the NuGet.Tools.vsix to reinstall NuGet This took me under a minute to do, and I was up and running. ASP.NET Web API Update Extravaganza! Uh, the Web API team is out of hand. They added a ton of new stuff: OData support, Tracing, and API Help Page generation. OData support Some people like OData. Some people start twitching when you mention it. If you're in the first group, this is for you. You can add a [Queryable] attribute to an API that returns an IQueryable<Whatever> and you get OData query support from your clients. Then, without any extra changes to your client or server code, your clients can send filters like this: /Suppliers?$filter=Name eq ‘Microsoft’ For more information about OData support in ASP.NET Web API, see Alex James' mega-post about it: OData support in ASP.NET Web API ASP.NET Web API Tracing Tracing makes it really easy to leverage the .NET Tracing system from within your ASP.NET Web API's. If you look at the \App_Start\WebApiConfig.cs file in new ASP.NET Web API project, you'll see a call to TraceConfig.Register(config). That calls into some code in the new \App_Start\TraceConfig.cs file: public static void Register(HttpConfiguration configuration) { if (configuration == null) { throw new ArgumentNullException("configuration"); } SystemDiagnosticsTraceWriter traceWriter = new SystemDiagnosticsTraceWriter() { MinimumLevel = TraceLevel.Info, IsVerbose = false }; configuration.Services.Replace(typeof(ITraceWriter), traceWriter); } As you can see, this is using the standard trace system, so you can extend it to any other trace listeners you'd like. To see how it works with the built in diagnostics trace writer, just run the application call some API's, and look at the Visual Studio Output window: iisexpress.exe Information: 0 : Request, Method=GET, Url=http://localhost:11147/api/Values, Message='http://localhost:11147/api/Values' iisexpress.exe Information: 0 : Message='Values', Operation=DefaultHttpControllerSelector.SelectController iisexpress.exe Information: 0 : Message='WebAPI.Controllers.ValuesController', Operation=DefaultHttpControllerActivator.Create iisexpress.exe Information: 0 : Message='WebAPI.Controllers.ValuesController', Operation=HttpControllerDescriptor.CreateController iisexpress.exe Information: 0 : Message='Selected action 'Get()'', Operation=ApiControllerActionSelector.SelectAction iisexpress.exe Information: 0 : Operation=HttpActionBinding.ExecuteBindingAsync iisexpress.exe Information: 0 : Operation=QueryableAttribute.ActionExecuting iisexpress.exe Information: 0 : Message='Action returned 'System.String[]'', Operation=ReflectedHttpActionDescriptor.ExecuteAsync iisexpress.exe Information: 0 : Message='Will use same 'JsonMediaTypeFormatter' formatter', Operation=JsonMediaTypeFormatter.GetPerRequestFormatterInstance iisexpress.exe Information: 0 : Message='Selected formatter='JsonMediaTypeFormatter', content-type='application/json; charset=utf-8'', Operation=DefaultContentNegotiator.Negotiate iisexpress.exe Information: 0 : Operation=ApiControllerActionInvoker.InvokeActionAsync, Status=200 (OK) iisexpress.exe Information: 0 : Operation=QueryableAttribute.ActionExecuted, Status=200 (OK) iisexpress.exe Information: 0 : Operation=ValuesController.ExecuteAsync, Status=200 (OK) iisexpress.exe Information: 0 : Response, Status=200 (OK), Method=GET, Url=http://localhost:11147/api/Values, Message='Content-type='application/json; charset=utf-8', content-length=unknown' iisexpress.exe Information: 0 : Operation=JsonMediaTypeFormatter.WriteToStreamAsync iisexpress.exe Information: 0 : Operation=ValuesController.Dispose API Help Page When you create a new ASP.NET Web API project, you'll see an API link in the header: Clicking the API link shows generated help documentation for your ASP.NET Web API controllers: And clicking on any of those APIs shows specific information: What's great is that this information is dynamically generated, so if you add your own new APIs it will automatically show useful and up to date help. This system is also completely extensible, so you can generate documentation in other formats or customize the HTML help as much as you'd like. The Help generation code is all included in an ASP.NET MVC Area: SignalR SignalR is a really slick open source project that was started by some ASP.NET team members in their spare time to add real-time communications capabilities to ASP.NET - and .NET applications in general. It allows you to handle long running communications channels between your server and multiple connected clients using the best communications channel they can both support - websockets if available, falling back all the way to old technologies like long polling if necessary for old browsers. SignalR remains an open source project, but now it's being included in ASP.NET (also open source, hooray!). That means there's real, official ASP.NET engineering work being put into SignalR, and it's even easier to use in an ASP.NET application. Now in any ASP.NET project type, you can right-click / Add / New Item... SignalR Hub or Persistent Connection. And much more... There's quite a bit more. You can find more info at http://asp.net/vnext, and we'll be adding more content as fast as we can. Watch my BUILD talk to see as I demonstrate these and other features in the ASP.NET Fall 2012 Update, as well as some other even futurey-er stuff!

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  • Dynamic Code for type casting Generic Types 'generically' in C#

    - by Rick Strahl
    C# is a strongly typed language and while that's a fundamental feature of the language there are more and more situations where dynamic types make a lot of sense. I've written quite a bit about how I use dynamic for creating new type extensions: Dynamic Types and DynamicObject References in C# Creating a dynamic, extensible C# Expando Object Creating a dynamic DataReader for dynamic Property Access Today I want to point out an example of a much simpler usage for dynamic that I use occasionally to get around potential static typing issues in C# code especially those concerning generic types. TypeCasting Generics Generic types have been around since .NET 2.0 I've run into a number of situations in the past - especially with generic types that don't implement specific interfaces that can be cast to - where I've been unable to properly cast an object when it's passed to a method or assigned to a property. Granted often this can be a sign of bad design, but in at least some situations the code that needs to be integrated is not under my control so I have to make due with what's available or the parent object is too complex or intermingled to be easily refactored to a new usage scenario. Here's an example that I ran into in my own RazorHosting library - so I have really no excuse, but I also don't see another clean way around it in this case. A Generic Example Imagine I've implemented a generic type like this: public class RazorEngine<TBaseTemplateType> where TBaseTemplateType : RazorTemplateBase, new() You can now happily instantiate new generic versions of this type with custom template bases or even a non-generic version which is implemented like this: public class RazorEngine : RazorEngine<RazorTemplateBase> { public RazorEngine() : base() { } } To instantiate one: var engine = new RazorEngine<MyCustomRazorTemplate>(); Now imagine that the template class receives a reference to the engine when it's instantiated. This code is fired as part of the Engine pipeline when it gets ready to execute the template. It instantiates the template and assigns itself to the template: var template = new TBaseTemplateType() { Engine = this } The problem here is that possibly many variations of RazorEngine<T> can be passed. I can have RazorTemplateBase, RazorFolderHostTemplateBase, CustomRazorTemplateBase etc. as generic parameters and the Engine property has to reflect that somehow. So, how would I cast that? My first inclination was to use an interface on the engine class and then cast to the interface.  Generally that works, but unfortunately here the engine class is generic and has a few members that require the template type in the member signatures. So while I certainly can implement an interface: public interface IRazorEngine<TBaseTemplateType> it doesn't really help for passing this generically templated object to the template class - I still can't cast it if multiple differently typed versions of the generic type could be passed. I have the exact same issue in that I can't specify a 'generic' generic parameter, since there's no underlying base type that's common. In light of this I decided on using object and the following syntax for the property (and the same would be true for a method parameter): public class RazorTemplateBase :MarshalByRefObject,IDisposable { public object Engine {get;set; } } Now because the Engine property is a non-typed object, when I need to do something with this value, I still have no way to cast it explicitly. What I really would need is: public RazorEngine<> Engine { get; set; } but that's not possible. Dynamic to the Rescue Luckily with the dynamic type this sort of thing can be mitigated fairly easily. For example here's a method that uses the Engine property and uses the well known class interface by simply casting the plain object reference to dynamic and then firing away on the properties and methods of the base template class that are common to all templates:/// <summary> /// Allows rendering a dynamic template from a string template /// passing in a model. This is like rendering a partial /// but providing the input as a /// </summary> public virtual string RenderTemplate(string template,object model) { if (template == null) return string.Empty; // if there's no template markup if(!template.Contains("@")) return template; // use dynamic to get around generic type casting dynamic engine = Engine; string result = engine.RenderTemplate(template, model); if (result == null) throw new ApplicationException("RenderTemplate failed: " + engine.ErrorMessage); return result; } Prior to .NET 4.0  I would have had to use Reflection for this sort of thing which would have a been a heck of a lot more verbose, but dynamic makes this so much easier and cleaner and in this case at least the overhead is negliable since it's a single dynamic operation on an otherwise very complex operation call. Dynamic as  a Bailout Sometimes this sort of thing often reeks of a design flaw, and I agree that in hindsight this could have been designed differently. But as is often the case this particular scenario wasn't planned for originally and removing the generic signatures from the base type would break a ton of other code in the framework. Given the existing fairly complex engine design, refactoring an interface to remove generic types just to make this particular code work would have been overkill. Instead dynamic provides a nice and simple and relatively clean solution. Now if there were many other places where this occurs I would probably consider reworking the code to make this cleaner but given this isolated instance and relatively low profile operation use of dynamic seems a valid choice for me. This solution really works anywhere where you might end up with an inheritance structure that doesn't have a common base or interface that is sufficient. In the example above I know what I'm getting but there's no common base type that I can cast to. All that said, it's a good idea to think about use of dynamic before you rush in. In many situations there are alternatives that can still work with static typing. Dynamic definitely has some overhead compared to direct static access of objects, so if possible we should definitely stick to static typing. In the example above the application already uses dynamics extensively for dynamic page page templating and passing models around so introducing dynamics here has very little additional overhead. The operation itself also fires of a fairly resource heavy operation where the overhead of a couple of dynamic member accesses are not a performance issue. So, what's your experience with dynamic as a bailout mechanism? © Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp   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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