jake a smith - Page 63 - Developer IT

Windows 7 laptop with two active network connections will not perform DNS AAAA lookup under certain conditions

- by Jeff Loughridge

My laptop has two network interfaces. The Ethernet interface connects directly to my provider's edge router. It obtains an IPv6 address via SLAAC. I manually set an IPv6 DNS server. The wireless interface connects to a CPE router that doesn't understand IPv6. If the wireless interface is disabled, I can reach the IPv6 Internet with no problems using the Ethernet interface. I run into problems when both interfaces are enabled and the wireless interface get its IPv4 DNS server via DHCP. Let's look at two scenarios. Wireless interface obtains IPv4 DNS server via DHCP - The CPE router (192.168.0.1) sends its address as the DNS server. In this scenario, Windows 7 will not perform AAAA lookups. The browser uses IPv4 transit to reach dual stack web sites. I can't reach IPv6-only web sites using domain names. I can reach IPv6-enabled web sites using IPv6 literals instead of the domain name. Wireless interface is manually configured with OpenDNS DNS server - Windows 7 performs AAAA lookups using IPv6 transit (via the Ethernet). Everything works fine. My dual homed set-up is definitely not standard. Still, the behavior is very strange to me. A valid IPv6 interface exists in my Ethernet interface. Why won't Windows attempt AAAA lookups in scenario #1? I've included the output of ipconfig /all and netstat -rn. C:\Program Files\Console>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : jake Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : res.openband.net Wireless LAN adapter Wireless Network Connection 2: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft Virtual WiFi Miniport Adapter Physical Address. . . . . . . . . : C0-CB-38-06-54-F9 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Wireless LAN adapter Wireless Network Connection: Connection-specific DNS Suffix . : res.openband.net Description . . . . . . . . . . . : DW1520 Wireless-N WLAN Half-Mini Card Physical Address. . . . . . . . . : C0-CB-38-06-54-F9 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::fc39:9293:7d01:4a75%13(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.0.105(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Wednesday, July 11, 2012 7:35:21 AM Lease Expires . . . . . . . . . . : Thursday, July 12, 2012 9:49:46 AM Default Gateway . . . . . . . . . : 192.168.0.1 DHCP Server . . . . . . . . . . . : 192.168.0.1 DHCPv6 IAID . . . . . . . . . . . : 364956472 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C DNS Servers . . . . . . . . . . . : 208.67.222.222 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : res.openband.net Description . . . . . . . . . . . : Intel(R) 82577LM Gigabit Network Connection Physical Address. . . . . . . . . : 5C-26-0A-03-23-5C DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IPv6 Address. . . . . . . . . . . : 2607:2600:1:850:c0e9:211a:fd05:4e0b(Preferred) Temporary IPv6 Address. . . . . . : 2607:2600:1:850:3d29:1839:62db:c4c1(Preferred) Link-local IPv6 Address . . . . . : fe80::c0e9:211a:fd05:4e0b%12(Preferred) IPv4 Address. . . . . . . . . . . : 10.52.2.51(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.254.0 Lease Obtained. . . . . . . . . . : Monday, July 09, 2012 8:55:07 AM Lease Expires . . . . . . . . . . : Thursday, July 12, 2012 7:30:05 AM Default Gateway . . . . . . . . . : fe80::214:6aff:fe51:7f3f%12 10.52.2.1 DHCP Server . . . . . . . . . . . : 216.40.77.244 DNS Servers . . . . . . . . . . . : 2620:0:ccc::2 2620:0:ccd::2 216.40.77.126 216.40.77.244 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter VMware Network Adapter VMnet1: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet1 Physical Address. . . . . . . . . : 00-50-56-C0-00-01 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::4c61:495b:229e:281e%14(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.40.1(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : DHCPv6 IAID . . . . . . . . . . . : 469782614 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1 fec0:0:0:ffff::2%1 fec0:0:0:ffff::3%1 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter VMware Network Adapter VMnet8: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet8 Physical Address. . . . . . . . . : 00-50-56-C0-00-08 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::f996:61eb:8c00:45e6%15(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.17.1(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : DHCPv6 IAID . . . . . . . . . . . : 486559830 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1 fec0:0:0:ffff::2%1 fec0:0:0:ffff::3%1 NetBIOS over Tcpip. . . . . . . . : Enabled C:\Program Files\Console>netstat -rn =========================================================================== Interface List 17...c0 cb 38 06 54 f9 ......Microsoft Virtual WiFi Miniport Adapter 13...c0 cb 38 06 54 f9 ......DW1520 Wireless-N WLAN Half-Mini Card 12...5c 26 0a 03 23 5c ......Intel(R) 82577LM Gigabit Network Connection 11...5c ac 4c f8 b8 55 ......Bluetooth Device (Personal Area Network) 14...00 50 56 c0 00 01 ......VMware Virtual Ethernet Adapter for VMnet1 15...00 50 56 c0 00 08 ......VMware Virtual Ethernet Adapter for VMnet8 1...........................Software Loopback Interface 1 =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 10.52.2.1 10.52.2.51 10 0.0.0.0 0.0.0.0 192.168.0.1 192.168.0.105 100 10.52.2.0 255.255.254.0 On-link 10.52.2.51 261 10.52.2.51 255.255.255.255 On-link 10.52.2.51 261 10.52.3.255 255.255.255.255 On-link 10.52.2.51 261 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 192.168.0.0 255.255.255.0 On-link 192.168.0.105 306 192.168.0.105 255.255.255.255 On-link 192.168.0.105 306 192.168.0.255 255.255.255.255 On-link 192.168.0.105 306 192.168.17.0 255.255.255.0 On-link 192.168.17.1 276 192.168.17.1 255.255.255.255 On-link 192.168.17.1 276 192.168.17.255 255.255.255.255 On-link 192.168.17.1 276 192.168.40.0 255.255.255.0 On-link 192.168.40.1 276 192.168.40.1 255.255.255.255 On-link 192.168.40.1 276 192.168.40.255 255.255.255.255 On-link 192.168.40.1 276 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 10.52.2.51 261 224.0.0.0 240.0.0.0 On-link 192.168.0.105 306 224.0.0.0 240.0.0.0 On-link 192.168.40.1 276 224.0.0.0 240.0.0.0 On-link 192.168.17.1 276 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 10.52.2.51 261 255.255.255.255 255.255.255.255 On-link 192.168.0.105 306 255.255.255.255 255.255.255.255 On-link 192.168.40.1 276 255.255.255.255 255.255.255.255 On-link 192.168.17.1 276 =========================================================================== Persistent Routes: None IPv6 Route Table =========================================================================== Active Routes: If Metric Network Destination Gateway 12 261 ::/0 fe80::214:6aff:fe51:7f3f 1 306 ::1/128 On-link 12 13 2607:2600:1:850::/64 On-link 12 261 2607:2600:1:850:3d29:1839:62db:c4c1/128 On-link 12 261 2607:2600:1:850:c0e9:211a:fd05:4e0b/128 On-link 12 261 fe80::/64 On-link 13 281 fe80::/64 On-link 14 276 fe80::/64 On-link 15 276 fe80::/64 On-link 14 276 fe80::4c61:495b:229e:281e/128 On-link 12 261 fe80::c0e9:211a:fd05:4e0b/128 On-link 15 276 fe80::f996:61eb:8c00:45e6/128 On-link 13 281 fe80::fc39:9293:7d01:4a75/128 On-link 1 306 ff00::/8 On-link 12 261 ff00::/8 On-link 13 281 ff00::/8 On-link 14 276 ff00::/8 On-link 15 276 ff00::/8 On-link =========================================================================== Persistent Routes: None

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Introduction to the ASP.NET Web API

- by Stephen.Walther

I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html> Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "\n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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Introduction to the ASP.NET Web API

- by Stephen.Walther

I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html> Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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Building applications with WCF - Intro

- by skjagini

I am going to write series of articles using Windows Communication Framework (WCF) to develop client and server applications and this is the first part of that series. What is WCF As Juwal puts in his Programming WCF book, WCF provides an SDK for developing and deploying services on Windows, provides runtime environment to expose CLR types as services and consume services as CLR types. Building services with WCF is incredibly easy and it’s implementation provides a set of industry standards and off the shelf plumbing including service hosting, instance management, reliability, transaction management, security etc such that it greatly increases productivity Scenario: Lets consider a typical bank customer trying to create an account, deposit amount and transfer funds between accounts, i.e. checking and savings. To make it interesting, we are going to divide the functionality into multiple services and each of them working with database directly. We will run test cases with and without transactional support across services. In this post we will build contracts, services, data access layer, unit tests to verify end to end communication etc, nothing big stuff here and we dig into other features of the WCF in subsequent posts with incremental changes. In any distributed architecture we have two pieces i.e. services and clients. Services as the name implies provide functionality to execute various pieces of business logic on the server, and clients providing interaction to the end user. Services can be built with Web Services or with WCF. Service built on WCF have the advantage of binding independent, i.e. can run against TCP and HTTP protocol without any significant changes to the code. Solution Services Profile: For creating a new bank customer, getting details about existing customer ProfileContract ProfileService Checking Account: To get checking account balance, deposit or withdraw amount CheckingAccountContract CheckingAccountService Savings Account: To get savings account balance, deposit or withdraw amount SavingsAccountContract SavingsAccountService ServiceHost: To host services, i.e. running the services at particular address, binding and contract where client can connect to Client: Helps end user to use services like creating account and amount transfer between the accounts BankDAL: Data access layer to work with database BankDAL It’s no brainer not to use an ORM as many matured products are available currently in market including Linq2Sql, Entity Framework (EF), LLblGenPro etc. For this exercise I am going to use Entity Framework 4.0, CTP 5 with code first approach. There are two approaches when working with data, data driven and code driven. In data driven we start by designing tables and their constrains in database and generate entities in code while in code driven (code first) approach entities are defined in code and the metadata generated from the entities is used by the EF to create tables and table constrains. In previous versions the entity classes had to derive from EF specific base classes. In EF 4 it is not required to derive from any EF classes, the entities are not only persistence ignorant but also enable full test driven development using mock frameworks. Application consists of 3 entities, Customer entity which contains Customer details; CheckingAccount and SavingsAccount to hold the respective account balance. We could have introduced an Account base class for CheckingAccount and SavingsAccount which is certainly possible with EF mappings but to keep it simple we are just going to follow 1 –1 mapping between entity and table mappings. Lets start out by defining a class called Customer which will be mapped to Customer table, observe that the class is simply a plain old clr object (POCO) and has no reference to EF at all. using System; namespace BankDAL.Model { public class Customer { public int Id { get; set; } public string FullName { get; set; } public string Address { get; set; } public DateTime DateOfBirth { get; set; } } } In order to inform EF about the Customer entity we have to define a database context with properties of type DbSet<> for every POCO which needs to be mapped to a table in database. EF uses convention over configuration to generate the metadata resulting in much less configuration. using System.Data.Entity; namespace BankDAL.Model { public class BankDbContext: DbContext { public DbSet<Customer> Customers { get; set; } } } Entity constrains can be defined through attributes on Customer class or using fluent syntax (no need to muscle with xml files), CustomerConfiguration class. By defining constrains in a separate class we can maintain clean POCOs without corrupting entity classes with database specific information. using System; using System.Data.Entity.ModelConfiguration; namespace BankDAL.Model { public class CustomerConfiguration: EntityTypeConfiguration<Customer> { public CustomerConfiguration() { Initialize(); } private void Initialize() { //Setting the Primary Key this.HasKey(e => e.Id); //Setting required fields this.HasRequired(e => e.FullName); this.HasRequired(e => e.Address); //Todo: Can't create required constraint as DateOfBirth is not reference type, research it //this.HasRequired(e => e.DateOfBirth); } } } Any queries executed against Customers property in BankDbContext are executed against Cusomers table. By convention EF looks for connection string with key of BankDbContext when working with the context. We are going to define a helper class to work with Customer entity with methods for querying, adding new entity etc and these are known as repository classes, i.e., CustomerRepository using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CustomerRepository { private readonly IDbSet<Customer> _customers; public CustomerRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _customers = bankDbContext.Customers; } public IQueryable<Customer> Query() { return _customers; } public void Add(Customer customer) { _customers.Add(customer); } } } From the above code it is observable that the Query methods returns customers as IQueryable i.e. customers are retrieved only when actually used i.e. iterated. Returning as IQueryable also allows to execute filtering and joining statements from business logic using lamba expressions without cluttering the data access layer with tens of methods. Our CheckingAccountRepository and SavingsAccountRepository look very similar to each other using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CheckingAccountRepository { private readonly IDbSet<CheckingAccount> _checkingAccounts; public CheckingAccountRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _checkingAccounts = bankDbContext.CheckingAccounts; } public IQueryable<CheckingAccount> Query() { return _checkingAccounts; } public void Add(CheckingAccount account) { _checkingAccounts.Add(account); } public IQueryable<CheckingAccount> GetAccount(int customerId) { return (from act in _checkingAccounts where act.CustomerId == customerId select act); } } } The repository classes look very similar to each other for Query and Add methods, with the help of C# generics and implementing repository pattern (Martin Fowler) we can reduce the repeated code. Jarod from ElegantCode has posted an article on how to use repository pattern with EF which we will implement in the subsequent articles along with WCF Unity life time managers by Drew Contracts It is very easy to follow contract first approach with WCF, define the interface and append ServiceContract, OperationContract attributes. IProfile contract exposes functionality for creating customer and getting customer details. using System; using System.ServiceModel; using BankDAL.Model; namespace ProfileContract { [ServiceContract] public interface IProfile { [OperationContract] Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth); [OperationContract] Customer GetCustomer(int id); } } ICheckingAccount contract exposes functionality for working with checking account, i.e., getting balance, deposit and withdraw of amount. ISavingsAccount contract looks the same as checking account. using System.ServiceModel; namespace CheckingAccountContract { [ServiceContract] public interface ICheckingAccount { [OperationContract] decimal? GetCheckingAccountBalance(int customerId); [OperationContract] void DepositAmount(int customerId,decimal amount); [OperationContract] void WithdrawAmount(int customerId, decimal amount); } } Services Having covered the data access layer and contracts so far and here comes the core of the business logic, i.e. services. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } ProfileService implements the IProfile contract for creating customer and getting customer detail using CustomerRepository. using System; using System.Linq; using System.ServiceModel; using BankDAL; using BankDAL.Model; using BankDAL.Repositories; using ProfileContract; namespace ProfileService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Profile: IProfile { public Customer CreateAccount( string customerName, string address, DateTime dateOfBirth) { Customer cust = new Customer { FullName = customerName, Address = address, DateOfBirth = dateOfBirth }; using (var bankDbContext = new BankDbContext()) { new CustomerRepository(bankDbContext).Add(cust); bankDbContext.SaveChanges(); } return cust; } public Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth) { return CreateAccount(customerName, address, dateOfBirth); } public Customer GetCustomer(int id) { return new CustomerRepository(new BankDbContext()).Query() .Where(i => i.Id == id).FirstOrDefault(); } } } From the above code you shall observe that we are calling bankDBContext’s SaveChanges method and there is no save method specific to customer entity because EF manages all the changes centralized at the context level and all the pending changes so far are submitted in a batch and it is represented as Unit of Work. Similarly Checking service implements ICheckingAccount contract using CheckingAccountRepository, notice that we are throwing overdraft exception if the balance falls by zero. WCF has it’s own way of raising exceptions using fault contracts which will be explained in the subsequent articles. SavingsAccountService is similar to CheckingAccountService. using System; using System.Linq; using System.ServiceModel; using BankDAL.Model; using BankDAL.Repositories; using CheckingAccountContract; namespace CheckingAccountService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Checking:ICheckingAccount { public decimal? GetCheckingAccountBalance(int customerId) { using (var bankDbContext = new BankDbContext()) { CheckingAccount account = (new CheckingAccountRepository(bankDbContext) .GetAccount(customerId)).FirstOrDefault(); if (account != null) return account.Balance; return null; } } public void DepositAmount(int customerId, decimal amount) { using(var bankDbContext = new BankDbContext()) { var checkingAccountRepository = new CheckingAccountRepository(bankDbContext); CheckingAccount account = (checkingAccountRepository.GetAccount(customerId)) .FirstOrDefault(); if (account == null) { account = new CheckingAccount() { CustomerId = customerId }; checkingAccountRepository.Add(account); } account.Balance = account.Balance + amount; if (account.Balance < 0) throw new ApplicationException("Overdraft not accepted"); bankDbContext.SaveChanges(); } } public void WithdrawAmount(int customerId, decimal amount) { DepositAmount(customerId, -1*amount); } } } BankServiceHost The host acts as a glue binding contracts with it’s services, exposing the endpoints. The services can be exposed either through the code or configuration file, configuration file is preferred as it allows run time changes to service behavior even after deployment. We have 3 services and for each of the service you need to define name (the class that implements the service with fully qualified namespace) and endpoint known as ABC, i.e. address, binding and contract. We are using netTcpBinding and have defined the base address with for each of the contracts .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } <system.serviceModel> <services> <service name="ProfileService.Profile"> <endpoint binding="netTcpBinding" contract="ProfileContract.IProfile"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Profile"/> </baseAddresses> </host> </service> <service name="CheckingAccountService.Checking"> <endpoint binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Checking"/> </baseAddresses> </host> </service> <service name="SavingsAccountService.Savings"> <endpoint binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Savings"/> </baseAddresses> </host> </service> </services> </system.serviceModel> Have to open the services by creating service host which will handle the incoming requests from clients. using System; namespace ServiceHost { class Program { static void Main(string[] args) { CreateHosts(); Console.ReadLine(); } private static void CreateHosts() { CreateHost(typeof(ProfileService.Profile),"Profile Service"); CreateHost(typeof(SavingsAccountService.Savings), "Savings Account Service"); CreateHost(typeof(CheckingAccountService.Checking), "Checking Account Service"); } private static void CreateHost(Type type, string hostDescription) { System.ServiceModel.ServiceHost host = new System.ServiceModel.ServiceHost(type); host.Open(); if (host.ChannelDispatchers != null && host.ChannelDispatchers.Count != 0 && host.ChannelDispatchers[0].Listener != null) Console.WriteLine("Started: " + host.ChannelDispatchers[0].Listener.Uri); else Console.WriteLine("Failed to start:" + hostDescription); } } } BankClient The client has no knowledge about service business logic other than the functionality it exposes through the contract, end points and a proxy to work against. The endpoint data and server proxy can be generated by right clicking on the project reference and choosing ‘Add Service Reference’ and entering the service end point address. Or if you have access to source, you can manually reference contract dlls and update clients configuration file to point to the service end point if the server and client happens to be being built using .Net framework. One of the pros with the manual approach is you don’t have to work against messy code generated files. <system.serviceModel> <client> <endpoint name="tcpProfile" address="net.tcp://localhost:1000/Profile" binding="netTcpBinding" contract="ProfileContract.IProfile"/> <endpoint name="tcpCheckingAccount" address="net.tcp://localhost:1000/Checking" binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <endpoint name="tcpSavingsAccount" address="net.tcp://localhost:1000/Savings" binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> </client> </system.serviceModel> The client uses a façade to connect to the services using System.ServiceModel; using CheckingAccountContract; using ProfileContract; using SavingsAccountContract; namespace Client { public class ProxyFacade { public static IProfile ProfileProxy() { return (new ChannelFactory<IProfile>("tcpProfile")).CreateChannel(); } public static ICheckingAccount CheckingAccountProxy() { return (new ChannelFactory<ICheckingAccount>("tcpCheckingAccount")) .CreateChannel(); } public static ISavingsAccount SavingsAccountProxy() { return (new ChannelFactory<ISavingsAccount>("tcpSavingsAccount")) .CreateChannel(); } } } With that in place, lets get our unit tests going using System; using System.Diagnostics; using BankDAL.Model; using NUnit.Framework; using ProfileContract; namespace Client { [TestFixture] public class Tests { private void TransferFundsFromSavingsToCheckingAccount(int customerId, decimal amount) { ProxyFacade.CheckingAccountProxy().DepositAmount(customerId, amount); ProxyFacade.SavingsAccountProxy().WithdrawAmount(customerId, amount); } private void TransferFundsFromCheckingToSavingsAccount(int customerId, decimal amount) { ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, amount); ProxyFacade.CheckingAccountProxy().WithdrawAmount(customerId, amount); } [Test] public void CreateAndGetProfileTest() { IProfile profile = ProxyFacade.ProfileProxy(); const string customerName = "Tom"; int customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)).Id; Customer customer = profile.GetCustomer(customerId); Assert.AreEqual(customerName,customer.FullName); } [Test] public void DepositWithDrawAndTransferAmountTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Smith" + DateTime.Now.ToString("HH:mm:ss"); var customer = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)); // Deposit to Savings ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 100); ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 25); Assert.AreEqual(125, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Withdraw ProxyFacade.SavingsAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(95, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Deposit to Checking ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 60); ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 40); Assert.AreEqual(100, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Withdraw ProxyFacade.CheckingAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(70, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Savings to Checking TransferFundsFromSavingsToCheckingAccount(customer.Id,10); Assert.AreEqual(85, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Checking to Savings TransferFundsFromCheckingToSavingsAccount(customer.Id, 50); Assert.AreEqual(135, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(30, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); } [Test] public void FundTransfersWithOverDraftTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Angelina" + DateTime.Now.ToString("HH:mm:ss"); var customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1972, 1, 1)).Id; ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, 100); TransferFundsFromSavingsToCheckingAccount(customerId,80); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); try { TransferFundsFromSavingsToCheckingAccount(customerId,30); } catch (Exception e) { Debug.WriteLine(e.Message); } Assert.AreEqual(110, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); } } } We are creating a new instance of the channel for every operation, we will look into instance management and how creating a new instance of channel affects it in subsequent articles. The first two test cases deals with creation of Customer, deposit and withdraw of month between accounts. The last case, FundTransferWithOverDraftTest() is interesting. Customer starts with depositing $100 in SavingsAccount followed by transfer of $80 in to checking account resulting in $20 in savings account. Customer then initiates $30 transfer from Savings to Checking resulting in overdraft exception on Savings with $30 being deposited to Checking. As we are not running both the requests in transactions the customer ends up with more amount than what he started with $100. In subsequent posts we will look into transactions handling. Make sure the ServiceHost project is set as start up project and start the solution. Run the test cases either from NUnit client or TestDriven.Net/Resharper which ever is your favorite tool. Make sure you have updated the data base connection string in the ServiceHost config file to point to your local database

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Nested property binding

- by EtherealMonkey

Recently, I have been trying to wrap my mind around the BindingList<T> and INotifyPropertChanged. More specifically - How do I make a collection of objects (having objects as properties) which will allow me to subscribe to events throughout the tree? To that end, I have examined the code offered as examples by others. One such project that I downloaded was Nested Property Binding - CodeProject by "seesharper". Now, the article explains the implementation, but there was a question by "Someone@AnotherWorld" about "INotifyPropertyChanged in nested objects". His question was: Hi, nice stuff! But after a couple of time using your solution I realize the ObjectBindingSource ignores the PropertyChanged event of nested objects. E.g. I've got a class 'Foo' with two properties named 'Name' and 'Bar'. 'Name' is a string an 'Bar' reference an instance of class 'Bar', which has a 'Name' property of type string too and both classes implements INotifyPropertyChanged. With your binding source reading and writing with both properties ('Name' and 'Bar_Name') works fine but the PropertyChanged event works only for the 'Name' property, because the binding source listen only for events of 'Foo'. One workaround is to retrigger the PropertyChanged event in the appropriate class (here 'Foo'). What's very unclean! The other approach would be to extend ObjectBindingSource so that all owner of nested property which implements INotifyPropertyChanged get used for receive changes, but how? Thanks! I had asked about BindingList<T> yesterday and received a good answer from Aaronaught. In my question, I had a similar point as "Someone@AnotherWorld": if Keywords were to implement INotifyPropertyChanged, would changes be accessible to the BindingList through the ScannedImage object? To which Aaronaught's response was: No, they will not. BindingList only looks at the specific object in the list, it has no ability to scan all dependencies and monitor everything in the graph (nor would that always be a good idea, if it were possible). I understand Aaronaught's comment regarding this behavior not necessarily being a good idea. Additionally, his suggestion to have my bound object "relay" events on behalf of it's member objects works fine and is perfectly acceptable. For me, "re-triggering" the PropertyChanged event does not seem so unclean as "Someone@AnotherWorld" laments. I do understand why he protests - in the interest of loosely coupled objects. However, I believe that coupling between objects that are part of a composition is logical and not so undesirable as this may be in other scenarios. (I am a newb, so I could be waaayyy off base.) Anyway, in the interest of exploring an answer to the question by "Someone@AnotherWorld", I altered the MainForm.cs file of the example project from Nested Property Binding - CodeProject by "seesharper" to the following: using System; using System.Collections.Generic; using System.ComponentModel; using System.Core.ComponentModel; using System.Windows.Forms; namespace ObjectBindingSourceDemo { public partial class MainForm : Form { private readonly List<Customer> _customers = new List<Customer>(); private readonly List<Product> _products = new List<Product>(); private List<Order> orders; public MainForm() { InitializeComponent(); dataGridView1.AutoGenerateColumns = false; dataGridView2.AutoGenerateColumns = false; CreateData(); } private void CreateData() { _customers.Add( new Customer(1, "Jane Wilson", new Address("98104", "6657 Sand Pointe Lane", "Seattle", "USA"))); _customers.Add( new Customer(1, "Bill Smith", new Address("94109", "5725 Glaze Drive", "San Francisco", "USA"))); _customers.Add( new Customer(1, "Samantha Brown", null)); _products.Add(new Product(1, "Keyboard", 49.99)); _products.Add(new Product(2, "Mouse", 10.99)); _products.Add(new Product(3, "PC", 599.99)); _products.Add(new Product(4, "Monitor", 299.99)); _products.Add(new Product(5, "LapTop", 799.99)); _products.Add(new Product(6, "Harddisc", 89.99)); customerBindingSource.DataSource = _customers; productBindingSource.DataSource = _products; orders = new List<Order>(); orders.Add(new Order(1, DateTime.Now, _customers[0])); orders.Add(new Order(2, DateTime.Now, _customers[1])); orders.Add(new Order(3, DateTime.Now, _customers[2])); #region Added by me OrderLine orderLine1 = new OrderLine(_products[0], 1); OrderLine orderLine2 = new OrderLine(_products[1], 3); orderLine1.PropertyChanged += new PropertyChangedEventHandler(OrderLineChanged); orderLine2.PropertyChanged += new PropertyChangedEventHandler(OrderLineChanged); orders[0].OrderLines.Add(orderLine1); orders[0].OrderLines.Add(orderLine2); #endregion // Removed by me in lieu of region above. //orders[0].OrderLines.Add(new OrderLine(_products[0], 1)); //orders[0].OrderLines.Add(new OrderLine(_products[1], 3)); ordersBindingSource.DataSource = orders; } #region Added by me // Have to wait until the form is Shown to wire up the events // for orderDetailsBindingSource. Otherwise, they are triggered // during MainForm().InitializeComponent(). private void MainForm_Shown(object sender, EventArgs e) { orderDetailsBindingSource.AddingNew += new AddingNewEventHandler(orderDetailsBindSrc_AddingNew); orderDetailsBindingSource.CurrentItemChanged += new EventHandler(orderDetailsBindSrc_CurrentItemChanged); orderDetailsBindingSource.ListChanged += new ListChangedEventHandler(orderDetailsBindSrc_ListChanged); } private void orderDetailsBindSrc_AddingNew( object sender, AddingNewEventArgs e) { } private void orderDetailsBindSrc_CurrentItemChanged( object sender, EventArgs e) { } private void orderDetailsBindSrc_ListChanged( object sender, ListChangedEventArgs e) { ObjectBindingSource bindingSource = (ObjectBindingSource)sender; if (!(bindingSource.Current == null)) { // Unsure if GetType().ToString() is required b/c ToString() // *seems* // to return the same value. if (bindingSource.Current.GetType().ToString() == "ObjectBindingSourceDemo.OrderLine") { if (e.ListChangedType == ListChangedType.ItemAdded) { // I wish that I knew of a way to determine // if the 'PropertyChanged' delegate assignment is null. // I don't like the current test, but it seems to work. if (orders[ ordersBindingSource.Position].OrderLines[ e.NewIndex].Product == null) { orders[ ordersBindingSource.Position].OrderLines[ e.NewIndex].PropertyChanged += new PropertyChangedEventHandler( OrderLineChanged); } } if (e.ListChangedType == ListChangedType.ItemDeleted) { // Will throw exception when leaving // an OrderLine row with unitialized properties. // // I presume this is because the item // has already been 'disposed' of at this point. // *but* // Will it be actually be released from memory // if the delegate assignment for PropertyChanged // was never removed??? if (orders[ ordersBindingSource.Position].OrderLines[ e.NewIndex].Product != null) { orders[ ordersBindingSource.Position].OrderLines[ e.NewIndex].PropertyChanged -= new PropertyChangedEventHandler( OrderLineChanged); } } } } } private void OrderLineChanged(object sender, PropertyChangedEventArgs e) { MessageBox.Show(e.PropertyName, "Property Changed:"); } #endregion } } In the method private void orderDetailsBindSrc_ListChanged(object sender, ListChangedEventArgs e) I am able to hook up the PropertyChangedEventHandler to the OrderLine object as it is being created. However, I cannot seem to find a way to unhook the PropertyChangedEventHandler from the OrderLine object before it is being removed from the orders[i].OrderLines list. So, my questions are: Am I simply trying to do something that is very, very wrong here? Will the OrderLines object that I add the delegate assignments to ever be released from memory if the assignment is not removed? Is there a "sane" method of achieving this scenario? Also, note that this question is not specifically related to my prior. I have actually solved the issue which had prompted me to inquire before. However, I have reached a point with this particular topic of discovery where my curiosity has exceeded my patience - hopefully someone here can shed some light on this?

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Please help me understand why my XSL Transform is not transforming

- by Damovisa

I'm trying to transform one XML format to another using XSL. Try as I might, I can't seem to get a result. I've hacked away at this for a while now and I've had no success. I'm not even getting any exceptions. I'm going to post the entire code and hopefully someone can help me work out what I've done wrong. I'm aware there are likely to be problems in the xsl I have in terms of selects and matches, but I'm not fussed about that at the moment. The output I'm getting is the input XML without any XML tags. The transformation is simply not occurring. Here's my XML Document: <?xml version="1.0"?> <Transactions> <Account> <PersonalAccount> <AccountNumber>066645621</AccountNumber> <AccountName>A Smith</AccountName> <CurrentBalance>-200125.96</CurrentBalance> <AvailableBalance>0</AvailableBalance> <AccountType>LOAN</AccountType> </PersonalAccount> </Account> <StartDate>2010-03-01T00:00:00</StartDate> <EndDate>2010-03-23T00:00:00</EndDate> <Items> <Transaction> <ErrorNumber>-1</ErrorNumber> <Amount>12000</Amount> <Reference>Transaction 1</Reference> <CreatedDate>0001-01-01T00:00:00</CreatedDate> <EffectiveDate>2010-03-15T00:00:00</EffectiveDate> <IsCredit>true</IsCredit> <Balance>-324000</Balance> </Transaction> <Transaction> <ErrorNumber>-1</ErrorNumber> <Amount>11000</Amount> <Reference>Transaction 2</Reference> <CreatedDate>0001-01-01T00:00:00</CreatedDate> <EffectiveDate>2010-03-14T00:00:00</EffectiveDate> <IsCredit>true</IsCredit> <Balance>-324000</Balance> </Transaction> </Items> </Transactions> Here's my XSLT: <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml" /> <xsl:param name="currentdate"></xsl:param> <xsl:template match="Transactions"> <xsl:element name="OFX"> <xsl:element name="SIGNONMSGSRSV1"> <xsl:element name="SONRS"> <xsl:element name="STATUS"> <xsl:element name="CODE">0</xsl:element> <xsl:element name="SEVERITY">INFO</xsl:element> </xsl:element> <xsl:element name="DTSERVER"><xsl:value-of select="$currentdate" /></xsl:element> <xsl:element name="LANGUAGE">ENG</xsl:element> </xsl:element> </xsl:element> <xsl:element name="BANKMSGSRSV1"> <xsl:element name="STMTTRNRS"> <xsl:element name="TRNUID">1</xsl:element> <xsl:element name="STATUS"> <xsl:element name="CODE">0</xsl:element> <xsl:element name="SEVERITY">INFO</xsl:element> </xsl:element> <xsl:element name="STMTRS"> <xsl:element name="CURDEF">AUD</xsl:element> <xsl:element name="BANKACCTFROM"> <xsl:element name="BANKID">RAMS</xsl:element> <xsl:element name="ACCTID"><xsl:value-of select="Account/PersonalAccount/AccountNumber" /></xsl:element> <xsl:element name="ACCTTYPE"><xsl:value-of select="Account/PersonalAccount/AccountType" /></xsl:element> </xsl:element> <xsl:element name="BANKTRANLIST"> <xsl:element name="DTSTART"><xsl:value-of select="StartDate" /></xsl:element> <xsl:element name="DTEND"><xsl:value-of select="EndDate" /></xsl:element> <xsl:for-each select="Items/Transaction"> <xsl:element name="STMTTRN"> <xsl:element name="TRNTYPE"><xsl:choose><xsl:when test="IsCredit">CREDIT</xsl:when><xsl:otherwise>DEBIT</xsl:otherwise></xsl:choose></xsl:element> <xsl:element name="DTPOSTED"><xsl:value-of select="EffectiveDate" /></xsl:element> <xsl:element name="DTUSER"><xsl:value-of select="CreatedDate" /></xsl:element> <xsl:element name="TRNAMT"><xsl:value-of select="Amount" /></xsl:element> <xsl:element name="FITID" /> <xsl:element name="NAME"><xsl:value-of select="Reference" /></xsl:element> <xsl:element name="MEMO"><xsl:value-of select="Reference" /></xsl:element> </xsl:element> </xsl:for-each> </xsl:element> <xsl:element name="LEDGERBAL"> <xsl:element name="BALAMT"><xsl:value-of select="Account/PersonalAccount/CurrentBalance" /></xsl:element> <xsl:element name="DTASOF"><xsl:value-of select="EndDate" /></xsl:element> </xsl:element> </xsl:element> </xsl:element> </xsl:element> </xsl:element> </xsl:template> </xsl:stylesheet> Here's my method to transform my XML: public string TransformToXml(XmlElement xmlElement, Dictionary<string, object> parameters) { string strReturn = ""; // Load the XSLT Document XslCompiledTransform xslt = new XslCompiledTransform(); xslt.Load(xsltFileName); // arguments XsltArgumentList args = new XsltArgumentList(); if (parameters != null && parameters.Count > 0) { foreach (string key in parameters.Keys) { args.AddParam(key, "", parameters[key]); } } //Create a memory stream to write to Stream objStream = new MemoryStream(); // Apply the transform xslt.Transform(xmlElement, args, objStream); objStream.Seek(0, SeekOrigin.Begin); // Read the contents of the stream StreamReader objSR = new StreamReader(objStream); strReturn = objSR.ReadToEnd(); return strReturn; } The contents of strReturn is an XML tag (<?xml version="1.0" encoding="utf-8"?>) followed by a raw dump of the contents of the original XML document, stripped of XML tags. What am I doing wrong here?

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How can I add headers to DualList control wpf

- by devnet247

Hi all I am trying to write a Dual List usercontrol in wpf. I am new to wpf and I am finding it quite difficult. This is something I have put together in a couple of hours.It's not that good but a start. I would be extremely grateful if somebody with wpf experience could improve it. The aim is to simplify the usage as much as possible I am kind of stuck. I would like the user of the DualList Control to be able to set up headers how do you do that. Do I need to expose some dependency properties in my control? At the moment when loading the user has to pass a ObservableCollection is there a better way? Could you have a look and possibly make any suggestions with some code? Thanks a lot!!!!! xaml <Grid ShowGridLines="False"> <Grid.ColumnDefinitions> <ColumnDefinition Width="*"/> <ColumnDefinition Width="25px"></ColumnDefinition> <ColumnDefinition Width="*"/> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="*"></RowDefinition> </Grid.RowDefinitions> <StackPanel Orientation="Vertical" Grid.Column="0" Grid.Row="0"> <Label Name="lblLeftTitle" Content="Available"></Label> <ListView Name="lvwLeft"> </ListView> </StackPanel> <WrapPanel Grid.Column="1" Grid.Row="0"> <Button Name="btnMoveRight" Content=">" Width="25" Margin="0,35,0,0" Click="btnMoveRight_Click" /> <Button Name="btnMoveAllRight" Content=">>" Width="25" Margin="0,05,0,0" Click="btnMoveAllRight_Click" /> <Button Name="btnMoveLeft" Content="<" Width="25" Margin="0,25,0,0" Click="btnMoveLeft_Click" /> <Button Name="btnMoveAllLeft" Content="<<" Width="25" Margin="0,05,0,0" Click="btnMoveAllLeft_Click" /> </WrapPanel> <StackPanel Orientation="Vertical" Grid.Column="2" Grid.Row="0"> <Label Name="lblRightTitle" Content="Selected"></Label> <ListView Name="lvwRight"> </ListView> </StackPanel> </Grid> Client public partial class DualListTest { public ObservableCollection<ListViewItem> LeftList { get; set; } public ObservableCollection<ListViewItem> RightList { get; set; } public DualListTest() { InitializeComponent(); LoadCustomers(); LoadDualList(); } private void LoadDualList() { dualList1.Load(LeftList, RightList); } private void LoadCustomers() { //Pretend we are getting a list of Customers from a repository. //Some go in the left List(Good Customers) some go in the Right List(Bad Customers). LeftList = new ObservableCollection<ListViewItem>(); RightList = new ObservableCollection<ListViewItem>(); var customers = GetCustomers(); foreach (var customer in customers) { if (customer.Status == CustomerStatus.Good) { LeftList.Add(new ListViewItem { Content = customer }); } else { RightList.Add(new ListViewItem{Content=customer }); } } } private static IEnumerable<Customer> GetCustomers() { return new List<Customer> { new Customer {Name = "Jo Blogg", Status = CustomerStatus.Good}, new Customer {Name = "Rob Smith", Status = CustomerStatus.Good}, new Customer {Name = "Michel Platini", Status = CustomerStatus.Good}, new Customer {Name = "Roberto Baggio", Status = CustomerStatus.Good}, new Customer {Name = "Gio Surname", Status = CustomerStatus.Bad}, new Customer {Name = "Diego Maradona", Status = CustomerStatus.Bad} }; } } UserControl public partial class DualList:UserControl { public ObservableCollection<ListViewItem> LeftListCollection { get; set; } public ObservableCollection<ListViewItem> RightListCollection { get; set; } public DualList() { InitializeComponent(); } public void Load(ObservableCollection<ListViewItem> leftListCollection, ObservableCollection<ListViewItem> rightListCollection) { LeftListCollection = leftListCollection; RightListCollection = rightListCollection; lvwLeft.ItemsSource = leftListCollection; lvwRight.ItemsSource = rightListCollection; EnableButtons(); } public static DependencyProperty LeftTitleProperty = DependencyProperty.Register("LeftTitle", typeof(string), typeof(Label)); public static DependencyProperty RightTitleProperty = DependencyProperty.Register("RightTitle", typeof(string), typeof(Label)); public static DependencyProperty LeftListProperty = DependencyProperty.Register("LeftList", typeof(ListView), typeof(DualList)); public static DependencyProperty RightListProperty = DependencyProperty.Register("RightList", typeof(ListView), typeof(DualList)); public string LeftTitle { get { return (string)lblLeftTitle.Content; } set { lblLeftTitle.Content = value; } } public string RightTitle { get { return (string)lblRightTitle.Content; } set { lblRightTitle.Content = value; } } public ListView LeftList { get { return lvwLeft; } set { lvwLeft = value; } } public ListView RightList { get { return lvwRight; } set { lvwRight = value; } } private void EnableButtons() { if (lvwLeft.Items.Count > 0) { btnMoveRight.IsEnabled = true; btnMoveAllRight.IsEnabled = true; } else { btnMoveRight.IsEnabled = false; btnMoveAllRight.IsEnabled = false; } if (lvwRight.Items.Count > 0) { btnMoveLeft.IsEnabled = true; btnMoveAllLeft.IsEnabled = true; } else { btnMoveLeft.IsEnabled = false; btnMoveAllLeft.IsEnabled = false; } if (lvwLeft.Items.Count != 0 || lvwRight.Items.Count != 0) return; btnMoveLeft.IsEnabled = false; btnMoveAllLeft.IsEnabled = false; btnMoveRight.IsEnabled = false; btnMoveAllRight.IsEnabled = false; } private void MoveRight() { while (lvwLeft.SelectedItems.Count > 0) { var selectedItem = (ListViewItem)lvwLeft.SelectedItem; LeftListCollection.Remove(selectedItem); RightListCollection.Add(selectedItem); } lvwRight.ItemsSource = RightListCollection; lvwLeft.ItemsSource = LeftListCollection; EnableButtons(); } private void MoveAllRight() { while (lvwLeft.Items.Count > 0) { var item = (ListViewItem)lvwLeft.Items[lvwLeft.Items.Count - 1]; LeftListCollection.Remove(item); RightListCollection.Add(item); } lvwRight.ItemsSource = RightListCollection; lvwLeft.ItemsSource = LeftListCollection; EnableButtons(); } private void MoveAllLeft() { while (lvwRight.Items.Count > 0) { var item = (ListViewItem)lvwRight.Items[lvwRight.Items.Count - 1]; RightListCollection.Remove(item); LeftListCollection.Add(item); } lvwRight.ItemsSource = RightListCollection; lvwLeft.ItemsSource = LeftListCollection; EnableButtons(); } private void MoveLeft() { while (lvwRight.SelectedItems.Count > 0) { var selectedCustomer = (ListViewItem)lvwRight.SelectedItem; LeftListCollection.Add(selectedCustomer); RightListCollection.Remove(selectedCustomer); } lvwRight.ItemsSource = RightListCollection; lvwLeft.ItemsSource = LeftListCollection; EnableButtons(); } private void btnMoveLeft_Click(object sender, RoutedEventArgs e) { MoveLeft(); } private void btnMoveAllLeft_Click(object sender, RoutedEventArgs e) { MoveAllLeft(); } private void btnMoveRight_Click(object sender, RoutedEventArgs e) { MoveRight(); } private void btnMoveAllRight_Click(object sender, RoutedEventArgs e) { MoveAllRight(); } }

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Array help Index out of range exeption was unhandled

- by Michael Quiles

I am trying to populate combo boxes from a text file using comma as a delimiter everything was working fine, but now when I debug I get the "Index out of range exeption was unhandled" warning. I guess I need a fresh pair of eyes to see where I went wrong, I commented on the line that gets the error //Fname = fields[1]; using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Drawing.Printing; using System.Linq; using System.Text; using System.Windows.Forms; using System.IO; namespace Sullivan_Payroll { public partial class xEmpForm : Form { bool complete = false; public xEmpForm() { InitializeComponent(); } private void xEmpForm_Resize(object sender, EventArgs e) { this.xCenterPanel.Left = Convert.ToInt16((this.Width - this.xCenterPanel.Width) / 2); this.xCenterPanel.Top = Convert.ToInt16((this.Height - this.xCenterPanel.Height) / 2); Refresh(); } private void exitToolStripMenuItem_Click(object sender, EventArgs e) { //Exits the application this.Close(); } private void xEmpForm_FormClosing(object sender, FormClosingEventArgs e) //use this on xtrip calculator { DialogResult Response; if (complete == true) { Application.Exit(); } else { Response = MessageBox.Show("Are you sure you want to Exit?", "Exit", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2); if (Response == DialogResult.No) { complete = false; e.Cancel = true; } else { complete = true; Application.Exit(); } } } private void xEmpForm_Load(object sender, EventArgs e) { //file sources string fileDept = "source\\Department.txt"; string fileSex = "source\\Sex.txt"; string fileStatus = "source\\Status.txt"; if (File.Exists(fileDept)) { using (System.IO.StreamReader sr = System.IO.File.OpenText(fileDept)) { string dept = ""; while ((dept = sr.ReadLine()) != null) { this.xDeptComboBox.Items.Add(dept); } } } else { MessageBox.Show("The Department file can not be found.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } if (File.Exists(fileSex)) { using (System.IO.StreamReader sr = System.IO.File.OpenText(fileSex)) { string sex = ""; while ((sex = sr.ReadLine()) != null) { this.xSexComboBox.Items.Add(sex); } } } else { MessageBox.Show("The Sex file can not be found.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } if (File.Exists(fileStatus)) { using (System.IO.StreamReader sr = System.IO.File.OpenText(fileStatus)) { string status = ""; while ((status = sr.ReadLine()) != null) { this.xStatusComboBox.Items.Add(status); } } } else { MessageBox.Show("The Status file can not be found.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } } private void xFileSaveMenuItem_Click(object sender, EventArgs e) { { const string fileNew = "source\\New Staff.txt"; string recordIn; FileStream outFile = new FileStream(fileNew, FileMode.Create, FileAccess.Write); StreamWriter writer = new StreamWriter(outFile); for (int count = 0; count <= this.xEmployeeListBox.Items.Count - 1; count++) { this.xEmployeeListBox.SelectedIndex = count; recordIn = this.xEmployeeListBox.SelectedItem.ToString(); writer.WriteLine(recordIn); } writer.Close(); outFile.Close(); this.xDeptComboBox.SelectedIndex = -1; this.xStatusComboBox.SelectedIndex = -1; this.xSexComboBox.SelectedIndex = -1; MessageBox.Show("your file is saved"); } } private void xViewFacultyMenuItem_Click(object sender, EventArgs e) { const string fileStaff = "source\\Staff.txt"; const char DELIM = ','; string Lname, Fname, Depart, Stat, Sex, Salary, cDept, cStat, cSex; double Gtotal; string recordIn; string[] fields; cDept = this.xDeptComboBox.SelectedItem.ToString(); cStat = this.xStatusComboBox.SelectedItem.ToString(); cSex = this.xSexComboBox.SelectedItem.ToString(); FileStream inFile = new FileStream(fileStaff, FileMode.Open, FileAccess.Read); StreamReader reader = new StreamReader(inFile); recordIn = reader.ReadLine(); while (recordIn != null) { fields = recordIn.Split(DELIM); Lname = fields[0]; Fname = fields[1]; // this is where the error appears Depart = fields[2]; Stat = fields[3]; Sex = fields[4]; Salary = fields[5]; Fname = fields[1].TrimStart(null); Depart = fields[2].TrimStart(null); Stat = fields[3].TrimStart(null); Sex = fields[4].TrimStart(null); Salary = fields[5].TrimStart(null); Gtotal = double.Parse(Salary); if (Depart == cDept && cStat == Stat && cSex == Sex) { this.xEmployeeListBox.Items.Add(recordIn); } recordIn = reader.ReadLine(); } reader.Close(); inFile.Close(); if (this.xEmployeeListBox.Items.Count >= 1) { this.xFileSaveMenuItem.Enabled = true; this.xFilePrintMenuItem.Enabled = true; this.xEditClearMenuItem.Enabled = true; } else { this.xFileSaveMenuItem.Enabled = false; this.xFilePrintMenuItem.Enabled = false; this.xEditClearMenuItem.Enabled = false; MessageBox.Show("Records not found"); } } private void xEditClearMenuItem_Click(object sender, EventArgs e) { this.xEmployeeListBox.Items.Clear(); this.xDeptComboBox.SelectedIndex = -1; this.xStatusComboBox.SelectedIndex = -1; this.xSexComboBox.SelectedIndex = -1; this.xFileSaveMenuItem.Enabled = false; this.xFilePrintMenuItem.Enabled = false; this.xEditClearMenuItem.Enabled = false; } } } Source file -- Anderson, Kristen, Accounting, Assistant, Female, 43155 Ball, Robin, Accounting, Instructor, Female, 42723 Chin, Roger, Accounting, Full, Male,59281 Coats, William, Accounting, Assistant, Male, 45371 Doepke, Cheryl, Accounting, Full, Female, 52105 Downs, Clifton, Accounting, Associate, Male, 46887 Garafano, Karen, Finance, Associate, Female, 49000 Hill, Trevor, Management, Instructor, Male, 38590 Jackson, Carole, Accounting, Instructor, Female, 38781 Jacobson, Andrew, Management, Full, Male, 56281 Lewis, Karl, Management, Associate, Male, 48387 Mack, Kevin, Management, Assistant, Male, 45000 McKaye, Susan, Management, Instructor, Female, 43979 Nelsen, Beth, Finance, Full, Female, 52339 Nelson, Dale, Accounting, Full, Male, 54578 Palermo, Sheryl, Accounting, Associate, Female, 45617 Rais, Mary, Finance, Instructor, Female, 27000 Scheib, Earl, Management, Instructor, Male, 37389 Smith, Tom, Finance, Full, Male, 57167 Smythe, Janice, Management, Associate, Female, 46887 True, David, Accounting, Full, Male, 53181 Young, Jeff, Management, Assistant, Male, 43513

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In Flex, how to drag a component into a column of DataGrid (not the whole DataGrid)?

- by Yousui

Hi guys, I have a custom component: <?xml version="1.0" encoding="utf-8"?> <s:Group xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx"> <fx:Declarations> </fx:Declarations> <fx:Script> <![CDATA[ [Bindable] public var label:String = "don't know"; [Bindable] public var imageName:String = "x.gif"; ]]> </fx:Script> <s:HGroup paddingLeft="8" paddingTop="8" paddingRight="8" paddingBottom="8"> <mx:Image id="img" source="assets/{imageName}" /> <s:Label text="{label}"/> </s:HGroup> </s:Group> and a custom render, which will be used in my DataGrid: <?xml version="1.0" encoding="utf-8"?> <s:MXDataGridItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" focusEnabled="true" xmlns:components="components.*"> <s:VGroup> <components:Person label="{dataGridListData.label}"> </components:Person> </s:VGroup> </s:MXDataGridItemRenderer> This is my application: <?xml version="1.0" encoding="utf-8"?> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" xmlns:services="services.*"> <s:layout> <s:VerticalLayout/> </s:layout> <fx:Script> <![CDATA[ import mx.collections.ArrayCollection; import mx.controls.Alert; import mx.controls.Image; import mx.rpc.events.ResultEvent; import mx.utils.ArrayUtil; ]]> </fx:Script> <fx:Declarations> <fx:XMLList id="employees"> <employee> <name>Christina Coenraets</name> <phone>555-219-2270</phone> <email>[email protected]</email> <active>true</active> <image>assets/001.png</image> </employee> <employee> <name>Joanne Wall</name> <phone>555-219-2012</phone> <email>[email protected]</email> <active>true</active> <image>assets/002.png</image> </employee> <employee> <name>Maurice Smith</name> <phone>555-219-2012</phone> <email>[email protected]</email> <active>false</active> <image>assets/003.png</image> </employee> <employee> <name>Mary Jones</name> <phone>555-219-2000</phone> <email>[email protected]</email> <active>true</active> <image>assets/004.png</image> </employee> </fx:XMLList> </fx:Declarations> <s:HGroup> <mx:DataGrid dataProvider="{employees}" width="100%" dropEnabled="true"> <mx:columns> <mx:DataGridColumn headerText="Employee Name" dataField="name"/> <mx:DataGridColumn headerText="Email" dataField="email"/> <mx:DataGridColumn headerText="Image" dataField="image" itemRenderer="renderers.render1"/> </mx:columns> </mx:DataGrid> <s:List dragEnabled="true" dragMoveEnabled="false"> <s:dataProvider> <s:ArrayCollection> <fx:String>aaa</fx:String> <fx:String>bbb</fx:String> <fx:String>ccc</fx:String> <fx:String>ddd</fx:String> </s:ArrayCollection> </s:dataProvider> </s:List> </s:HGroup> </s:Application> Now what I want to do is let the user drag an one or more item from the left List component and drop at the third column of the DataGrid, then using the dragged data to create another <components:Person /> object. So in the final result, maybe the first line contains just one <components:Person /> object at the third column, the second line contains two <components:Person /> object at the third column and so on. Can this be implemented in Flex? How? Great thanks.

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I would like to filter XSL output based on a Radio button selection

- by Phil Speth

Here is my example I am trying to filter by year based on user selection: I assume some js or jQuery code would be needed: XML file: <?xml version="1.0" encoding="ISO-8859-1"?> <catalog> <cd> <title>Empire Burlesque3</title> <artist>Bob Dylan</artist> <country>USA</country> <company>Columbia</company> <price>10.90</price> <year>1985</year> </cd> <cd> <title>Hide your heart</title> <artist>Bonnie Tyler</artist> <country>UK</country> <company>CBS Records</company> <price>9.90</price> <year>1988</year> </cd> <cd> <title>Greatest Hits</title> <artist>Dolly Parton</artist> <country>USA</country> <company>RCA</company> <price>9.90</price> <year>1982</year> </cd> <cd> <title>Still got the blues</title> <artist>Gary Moore</artist> <country>UK</country> <company>Virgin records</company> <price>10.20</price> <year>1990</year> </cd> <cd> <title>Eros</title> <artist>Eros Ramazzotti</artist> <country>EU</country> <company>BMG</company> <price>9.90</price> <year>1997</year> </cd> <cd> <title>One night only</title> <artist>Bee Gees</artist> <country>UK</country> <company>Polydor</company> <price>10.90</price> <year>1998</year> </cd> <cd> <title>Sylvias Mother</title> <artist>Dr.Hook</artist> <country>UK</country> <company>CBS</company> <price>8.10</price> <year>1973</year> </cd> <cd> <title>Maggie May</title> <artist>Rod Stewart</artist> <country>UK</country> <company>Pickwick</company> <price>8.50</price> <year>1990</year> </cd> <cd> <title>Romanza</title> <artist>Andrea Bocelli</artist> <country>EU</country> <company>Polydor</company> <price>10.80</price> <year>1996</year> </cd> <cd> <title>When a man loves a woman</title> <artist>Percy Sledge</artist> <country>USA</country> <company>Atlantic</company> <price>8.70</price> <year>1987</year> </cd> <cd> <title>Black angel</title> <artist>Savage Rose</artist> <country>EU</country> <company>Mega</company> <price>10.90</price> <year>1995</year> </cd> <cd> <title>1999 Grammy Nominees</title> <artist>Many</artist> <country>USA</country> <company>Grammy</company> <price>10.20</price> <year>1999</year> </cd> <cd> <title>For the good times</title> <artist>Kenny Rogers</artist> <country>UK</country> <company>Mucik Master</company> <price>8.70</price> <year>1995</year> </cd> <cd> <title>Big Willie style</title> <artist>Will Smith</artist> <country>USA</country> <company>Columbia</company> <price>9.90</price> <year>1997</year> </cd> <cd> <title>Tupelo Honey</title> <artist>Van Morrison</artist> <country>UK</country> <company>Polydor</company> <price>8.20</price> <year>1971</year> </cd> <cd> <title>Soulsville</title> <artist>Jorn Hoel</artist> <country>Norway</country> <company>WEA</company> <price>7.90</price> <year>1996</year> </cd> <cd> <title>The very best of</title> <artist>Cat Stevens</artist> <country>UK</country> <company>Island</company> <price>8.90</price> <year>1990</year> </cd> <cd> <title>Stop</title> <artist>Sam Brown</artist> <country>UK</country> <company>A and M</company> <price>8.90</price> <year>1988</year> </cd> <cd> <title>Bridge of Spies</title> <artist>T`Pau</artist> <country>UK</country> <company>Siren</company> <price>7.90</price> <year>1987</year> </cd> <cd> <title>Private Dancer</title> <artist>Tina Turner</artist> <country>UK</country> <company>Capitol</company> <price>8.90</price> <year>1983</year> </cd> <cd> <title>Midt om natten</title> <artist>Kim Larsen</artist> <country>EU</country> <company>Medley</company> <price>7.80</price> <year>1983</year> </cd> <cd> <title>Pavarotti Gala Concert</title> <artist>Luciano Pavarotti</artist> <country>UK</country> <company>DECCA</company> <price>9.90</price> <year>1991</year> </cd> <cd> <title>The dock of the bay</title> <artist>Otis Redding</artist> <country>USA</country> <company>Atlantic</company> <price>7.90</price> <year>1987</year> </cd> <cd> <title>Picture book</title> <artist>Simply Red</artist> <country>EU</country> <company>Elektra</company> <price>7.20</price> <year>1985</year> </cd> <cd> <title>Red</title> <artist>The Communards</artist> <country>UK</country> <company>London</company> <price>7.80</price> <year>1987</year> </cd> <cd> <title>Unchain my heart</title> <artist>Joe Cocker</artist> <country>USA</country> <company>EMI</company> <price>8.20</price> <year>1987</year> </cd> </catalog> XSL File: <?xml version="1.0" encoding="ISO-8859-1"?>  <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="/"> <html> <body> <input type="radio" name="Cost" value="1980" checked="checked" /> 1980 <input type="radio" name="Cost" value="1990" /> 1990 <h2>My CD Collection</h2> <table border="1"> <tr bgcolor="#9acd32"> <th>Title</th> <th>Artist</th> </tr> <xsl:for-each select="catalog/cd"> <xsl:if test="year>1990"> <tr> <td><xsl:value-of select="title"/></td> <td><xsl:value-of select="artist"/></td> <td><xsl:value-of select="year"/></td> </tr> </xsl:if> </xsl:for-each> </table> </body> </html> </xsl:template> </xsl:stylesheet>

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