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  • Using jQuery to Insert a New Database Record

    - by Stephen Walther
    The goal of this blog entry is to explore the easiest way of inserting a new record into a database using jQuery and .NET. I’m going to explore two approaches: using Generic Handlers and using a WCF service (In a future blog entry I’ll take a look at OData and WCF Data Services). Create the ASP.NET Project I’ll start by creating a new empty ASP.NET application with Visual Studio 2010. Select the menu option File, New Project and select the ASP.NET Empty Web Application project template. Setup the Database and Data Model I’ll use my standard MoviesDB.mdf movies database. This database contains one table named Movies that looks like this: I’ll use the ADO.NET Entity Framework to represent my database data: Select the menu option Project, Add New Item and select the ADO.NET Entity Data Model project item. Name the data model MoviesDB.edmx and click the Add button. In the Choose Model Contents step, select Generate from database and click the Next button. In the Choose Your Data Connection step, leave all of the defaults and click the Next button. In the Choose Your Data Objects step, select the Movies table and click the Finish button. Unfortunately, Visual Studio 2010 cannot spell movie correctly :) You need to click on Movy and change the name of the class to Movie. In the Properties window, change the Entity Set Name to Movies. Using a Generic Handler In this section, we’ll use jQuery with an ASP.NET generic handler to insert a new record into the database. A generic handler is similar to an ASP.NET page, but it does not have any of the overhead. It consists of one method named ProcessRequest(). Select the menu option Project, Add New Item and select the Generic Handler project item. Name your new generic handler InsertMovie.ashx and click the Add button. Modify your handler so it looks like Listing 1: Listing 1 – InsertMovie.ashx using System.Web; namespace WebApplication1 { /// <summary> /// Inserts a new movie into the database /// </summary> public class InsertMovie : IHttpHandler { private MoviesDBEntities _dataContext = new MoviesDBEntities(); public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; // Extract form fields var title = context.Request["title"]; var director = context.Request["director"]; // Create movie to insert var movieToInsert = new Movie { Title = title, Director = director }; // Save new movie to DB _dataContext.AddToMovies(movieToInsert); _dataContext.SaveChanges(); // Return success context.Response.Write("success"); } public bool IsReusable { get { return true; } } } } In Listing 1, the ProcessRequest() method is used to retrieve a title and director from form parameters. Next, a new Movie is created with the form values. Finally, the new movie is saved to the database and the string “success” is returned. Using jQuery with the Generic Handler We can call the InsertMovie.ashx generic handler from jQuery by using the standard jQuery post() method. The following HTML page illustrates how you can retrieve form field values and post the values to the generic handler: Listing 2 – Default.htm <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Add Movie</title> <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js" type="text/javascript"></script> </head> <body> <form> <label>Title:</label> <input name="title" /> <br /> <label>Director:</label> <input name="director" /> </form> <button id="btnAdd">Add Movie</button> <script type="text/javascript"> $("#btnAdd").click(function () { $.post("InsertMovie.ashx", $("form").serialize(), insertCallback); }); function insertCallback(result) { if (result == "success") { alert("Movie added!"); } else { alert("Could not add movie!"); } } </script> </body> </html>     When you open the page in Listing 2 in a web browser, you get a simple HTML form: Notice that the page in Listing 2 includes the jQuery library. The jQuery library is included with the following SCRIPT tag: <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js" type="text/javascript"></script> The jQuery library is included on the Microsoft Ajax CDN so you can always easily include the jQuery library in your applications. You can learn more about the CDN at this website: http://www.asp.net/ajaxLibrary/cdn.ashx When you click the Add Movie button, the jQuery post() method is called to post the form data to the InsertMovie.ashx generic handler. Notice that the form values are serialized into a URL encoded string by calling the jQuery serialize() method. The serialize() method uses the name attribute of form fields and not the id attribute. Notes on this Approach This is a very low-level approach to interacting with .NET through jQuery – but it is simple and it works! And, you don’t need to use any JavaScript libraries in addition to the jQuery library to use this approach. The signature for the jQuery post() callback method looks like this: callback(data, textStatus, XmlHttpRequest) The second parameter, textStatus, returns the HTTP status code from the server. I tried returning different status codes from the generic handler with an eye towards implementing server validation by returning a status code such as 400 Bad Request when validation fails (see http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html ). I finally figured out that the callback is not invoked when the textStatus has any value other than “success”. Using a WCF Service As an alternative to posting to a generic handler, you can create a WCF service. You create a new WCF service by selecting the menu option Project, Add New Item and selecting the Ajax-enabled WCF Service project item. Name your WCF service InsertMovie.svc and click the Add button. Modify the WCF service so that it looks like Listing 3: Listing 3 – InsertMovie.svc using System.ServiceModel; using System.ServiceModel.Activation; namespace WebApplication1 { [ServiceBehavior(IncludeExceptionDetailInFaults=true)] [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class MovieService { private MoviesDBEntities _dataContext = new MoviesDBEntities(); [OperationContract] public bool Insert(string title, string director) { // Create movie to insert var movieToInsert = new Movie { Title = title, Director = director }; // Save new movie to DB _dataContext.AddToMovies(movieToInsert); _dataContext.SaveChanges(); // Return movie (with primary key) return true; } } }   The WCF service in Listing 3 uses the Entity Framework to insert a record into the Movies database table. The service always returns the value true. Notice that the service in Listing 3 includes the following attribute: [ServiceBehavior(IncludeExceptionDetailInFaults=true)] You need to include this attribute if you want to get detailed error information back to the client. When you are building an application, you should always include this attribute. When you are ready to release your application, you should remove this attribute for security reasons. Using jQuery with the WCF Service Calling a WCF service from jQuery requires a little more work than calling a generic handler from jQuery. Here are some good blog posts on some of the issues with using jQuery with WCF: http://encosia.com/2008/06/05/3-mistakes-to-avoid-when-using-jquery-with-aspnet-ajax/ http://encosia.com/2008/03/27/using-jquery-to-consume-aspnet-json-web-services/ http://weblogs.asp.net/scottgu/archive/2007/04/04/json-hijacking-and-how-asp-net-ajax-1-0-mitigates-these-attacks.aspx http://www.west-wind.com/Weblog/posts/896411.aspx http://www.west-wind.com/weblog/posts/324917.aspx http://professionalaspnet.com/archive/tags/WCF/default.aspx The primary requirement when calling WCF from jQuery is that the request use JSON: The request must include a content-type:application/json header. Any parameters included with the request must be JSON encoded. Unfortunately, jQuery does not include a method for serializing JSON (Although, oddly, jQuery does include a parseJSON() method for deserializing JSON). Therefore, we need to use an additional library to handle the JSON serialization. The page in Listing 4 illustrates how you can call a WCF service from jQuery. Listing 4 – Default2.aspx <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Add Movie</title> <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js" type="text/javascript"></script> <script src="Scripts/json2.js" type="text/javascript"></script> </head> <body> <form> <label>Title:</label> <input id="title" /> <br /> <label>Director:</label> <input id="director" /> </form> <button id="btnAdd">Add Movie</button> <script type="text/javascript"> $("#btnAdd").click(function () { // Convert the form into an object var data = { title: $("#title").val(), director: $("#director").val() }; // JSONify the data data = JSON.stringify(data); // Post it $.ajax({ type: "POST", contentType: "application/json; charset=utf-8", url: "MovieService.svc/Insert", data: data, dataType: "json", success: insertCallback }); }); function insertCallback(result) { // unwrap result result = result["d"]; if (result === true) { alert("Movie added!"); } else { alert("Could not add movie!"); } } </script> </body> </html> There are several things to notice about Listing 4. First, notice that the page includes both the jQuery library and Douglas Crockford’s JSON2 library: <script src="Scripts/json2.js" type="text/javascript"></script> You need to include the JSON2 library to serialize the form values into JSON. You can download the JSON2 library from the following location: http://www.json.org/js.html When you click the button to submit the form, the form data is converted into a JavaScript object: // Convert the form into an object var data = { title: $("#title").val(), director: $("#director").val() }; Next, the data is serialized into JSON using the JSON2 library: // JSONify the data var data = JSON.stringify(data); Finally, the form data is posted to the WCF service by calling the jQuery ajax() method: // Post it $.ajax({   type: "POST",   contentType: "application/json; charset=utf-8",   url: "MovieService.svc/Insert",   data: data,   dataType: "json",   success: insertCallback }); You can’t use the standard jQuery post() method because you must set the content-type of the request to be application/json. Otherwise, the WCF service will reject the request for security reasons. For details, see the Scott Guthrie blog post: http://weblogs.asp.net/scottgu/archive/2007/04/04/json-hijacking-and-how-asp-net-ajax-1-0-mitigates-these-attacks.aspx The insertCallback() method is called when the WCF service returns a response. This method looks like this: function insertCallback(result) {   // unwrap result   result = result["d"];   if (result === true) {       alert("Movie added!");   } else {     alert("Could not add movie!");   } } When we called the jQuery ajax() method, we set the dataType to JSON. That causes the jQuery ajax() method to deserialize the response from the WCF service from JSON into a JavaScript object automatically. The following value is passed to the insertCallback method: {"d":true} For security reasons, a WCF service always returns a response with a “d” wrapper. The following line of code removes the “d” wrapper: // unwrap result result = result["d"]; To learn more about the “d” wrapper, I recommend that you read the following blog posts: http://encosia.com/2009/02/10/a-breaking-change-between-versions-of-aspnet-ajax/ http://encosia.com/2009/06/29/never-worry-about-asp-net-ajaxs-d-again/ Summary In this blog entry, I explored two methods of inserting a database record using jQuery and .NET. First, we created a generic handler and called the handler from jQuery. This is a very low-level approach. However, it is a simple approach that works. Next, we looked at how you can call a WCF service using jQuery. This approach required a little more work because you need to serialize objects into JSON. We used the JSON2 library to perform the serialization. In the next blog post, I want to explore how you can use jQuery with OData and WCF Data Services.

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  • Design by Contract with Microsoft .Net Code Contract

    - by Fredrik N
    I have done some talks on different events and summits about Defensive Programming and Design by Contract, last time was at Cornerstone’s Developer Summit 2010. Next time will be at SweNug (Sweden .Net User Group). I decided to write a blog post about of some stuffs I was talking about. Users are a terrible thing! Protect your self from them ”Human users have a gift for doing the worst possible thing at the worst possible time.” – Michael T. Nygard, Release It! The kind of users Michael T. Nygard are talking about is the users of a system. We also have users that uses our code, the users I’m going to focus on is the users of our code. Me and you and another developers. “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” – Martin Fowler Good programmers also writes code that humans know how to use, good programmers also make sure software behave in a predictable manner despise inputs or user actions. Design by Contract   Design by Contract (DbC) is a way for us to make a contract between us (the code writer) and the users of our code. It’s about “If you give me this, I promise to give you this”. It’s not about business validations, that is something completely different that should be part of the domain model. DbC is to make sure the users of our code uses it in a correct way, and that we can rely on the contract and write code in a way where we know that the users will follow the contract. It will make it much easier for us to write code with a contract specified. Something like the following code is something we may see often: public void DoSomething(Object value) { value.DoIKnowThatICanDoThis(); } .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; } Where “value” can be uses directly or passed to other methods and later be used. What some of us can easily forget here is that the “value” can be “null”. We will probably not passing a null value, but someone else that uses our code maybe will do it. I think most of you (including me) have passed “null” into a method because you don’t know if the argument need to be specified to a valid value etc. I bet most of you also have got the “Null reference exception”. Sometimes this “Null reference exception” can be hard and take time to fix, because we need to search among our code to see where the “null” value was passed in etc. Wouldn’t it be much better if we can as early as possible specify that the value can’t not be null, so the users of our code also know it when the users starts to use our code, and before run time execution of the code? This is where DbC comes into the picture. We can use DbC to specify what we need, and by doing so we can rely on the contract when we write our code. So the code above can actually use the DoIKnowThatICanDoThis() method on the value object without being worried that the “value” can be null. The contract between the users of the code and us writing the code, says that the “value” can’t be null.   Pre- and Postconditions   When working with DbC we are specifying pre- and postconditions.  Precondition is a condition that should be met before a query or command is executed. An example of a precondition is: “The Value argument of the method can’t be null”, and we make sure the “value” isn’t null before the method is called. Postcondition is a condition that should be met when a command or query is completed, a postcondition will make sure the result is correct. An example of a postconditon is “The method will return a list with at least 1 item”. Commands an Quires When using DbC, we need to know what a Command and a Query is, because some principles that can be good to follow are based on commands and queries. A Command is something that will not return anything, like the SQL’s CREATE, UPDATE and DELETE. There are two kinds of Commands when using DbC, the Creation commands (for example a Constructor), and Others. Others can for example be a Command to add a value to a list, remove or update a value etc. //Creation commands public Stack(int size) //Other commands public void Push(object value); public void Remove(); .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; }   A Query, is something that will return something, for example an Attribute, Property or a Function, like the SQL’s SELECT.   There are two kinds of Queries, the Basic Queries  (Quires that aren’t based on another queries), and the Derived Queries, queries that is based on another queries. Here is an example of queries of a Stack: //Basic Queries public int Count; public object this[int index] { get; } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .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; } To understand about some principles that are good to follow when using DbC, we need to know about the Commands and different Queries. The 6 Principles When working with DbC, it’s advisable to follow some principles to make it easier to define and use contracts. The following DbC principles are: Separate commands and queries. Separate basic queries from derived queries. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries. For each command, write a postcondition that specifies the value of every basic query. For every query and command, decide on a suitable precondition. Write invariants to define unchanging properties of objects. Before I will write about each of them I want you to now that I’m going to use .Net 4.0 Code Contract. I will in the rest of the post uses a simple Stack (Yes I know, .Net already have a Stack class) to give you the basic understanding about using DbC. A Stack is a data structure where the first item in, will be the first item out. Here is a basic implementation of a Stack where not contract is specified yet: public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } //Is related to Count and this[] Query public object Top() { return this[Count]; } //Creation commands public Stack(uint size) { Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { this[++Count] = value; } public void Remove() { this[Count] = null; Count--; } } .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; }   Note: The Stack is implemented in a way to demonstrate the use of Code Contract in a simple way, the implementation may not look like how you would implement it, so don’t think this is the perfect Stack implementation, only used for demonstration.   Before I will go deeper into the principles I will simply mention how we can use the .Net Code Contract. I mention before about pre- and postcondition, is about “Require” something and to “Ensure” something. When using Code Contract, we will use a static class called “Contract” and is located in he “System.Diagnostics.Contracts” namespace. The contract must be specified at the top or our member statement block. To specify a precondition with Code Contract we uses the Contract.Requires method, and to specify a postcondition, we uses the Contract.Ensure method. Here is an example where both a pre- and postcondition are used: public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .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; }   The contract above requires that the Count is greater than 0, if not we can’t get the item at the Top of a Stack. We also Ensures that the results (By using the Contract.Result method, we can specify a postcondition that will check if the value returned from a method is correct) of the Top query is equal to this[Count].   1. Separate Commands and Queries   When working with DbC, it’s important to separate Command and Quires. A method should either be a command that performs an Action, or returning information to the caller, not both. By asking a question the answer shouldn’t be changed. The following is an example of a Command and a Query of a Stack: public void Push(object value) public object Top() .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; }   The Push is a command and will not return anything, just add a value to the Stack, the Top is a query to get the item at the top of the stack.   2. Separate basic queries from derived queries There are two different kinds of queries,  the basic queries that doesn’t rely on another queries, and derived queries that uses a basic query. The “Separate basic queries from derived queries” principle is about about that derived queries can be specified in terms of basic queries. So this principles is more about recognizing that a query is a derived query or a basic query. It will then make is much easier to follow the other principles. The following code shows a basic query and a derived query: //Basic Queries public uint Count; //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .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; }   We can see that IsEmpty will use the Count query, and that makes the IsEmpty a Derived query.   3. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries.   When the derived query is recognize we can follow the 3ed principle. For each derived query, we can create a postcondition that specifies what result our derived query will return in terms of one or more basic queries. Remember that DbC is about contracts between the users of the code and us writing the code. So we can’t use demand that the users will pass in a valid value, we must also ensure that we will give the users what the users wants, when the user is following our contract. The IsEmpty query of the Stack will use a Count query and that will make the IsEmpty a Derived query, so we should now write a postcondition that specified what results will be returned, in terms of using a basic query and in this case the Count query, //Basic Queries public uint Count; //Derived Queries public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } The Contract.Ensures is used to create a postcondition. The above code will make sure that the results of the IsEmpty (by using the Contract.Result to get the result of the IsEmpty method) is correct, that will say that the IsEmpty will be either true or false based on Count is equal to 0 or not. The postcondition are using a basic query, so the IsEmpty is now following the 3ed principle. We also have another Derived Query, the Top query, it will also need a postcondition and it uses all basic queries. The Result of the Top method must be the same value as the this[] query returns. //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count and this[] Query public object Top() { Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .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; }   4. For each command, write a postcondition that specifies the value of every basic query.   For each command we will create a postconditon that specifies the value of basic queries. If we look at the Stack implementation we will have three Commands, one Creation command, the Constructor, and two others commands, Push and Remove. Those commands need a postcondition and they should include basic query to follow the 4th principle. //Creation commands public Stack(uint size) { Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .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; }   As you can see the Create command will Ensures that Count will be 0 when the Stack is created, when a Stack is created there shouldn’t be any items in the stack. The Push command will take a value and put it into the Stack, when an item is pushed into the Stack, the Count need to be increased to know the number of items added to the Stack, and we must also make sure the item is really added to the Stack. The postconditon of the Push method will make sure the that old value of the Count (by using the Contract.OldValue we can get the value a Query has before the method is called)  plus 1 will be equal to the Count query, this is the way we can ensure that the Push will increase the Count with one. We also make sure the this[] query will now contain the item we pushed into the Stack. The Remove method must make sure the Count is decreased by one when the top item is removed from the Stack. The Commands is now following the 4th principle, where each command now have a postcondition that used the value of basic queries. Note: The principle says every basic Query, the Remove only used one Query the Count, it’s because this command can’t use the this[] query because an item is removed, so the only way to make sure an item is removed is to just use the Count query, so the Remove will still follow the principle.   5. For every query and command, decide on a suitable precondition.   We have now focused only on postcondition, now time for some preconditons. The 5th principle is about deciding a suitable preconditon for every query and command. If we starts to look at one of our basic queries (will not go through all Queries and commands here, just some of them) the this[] query, we can’t pass an index that is lower then 1 (.Net arrays and list are zero based, but not the stack in this blog post ;)) and the index can’t be lesser than the number of items in the stack. So here we will need a preconditon. public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } } .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; } Think about the Contract as an documentation about how to use the code in a correct way, so if the contract could be specified elsewhere (not part of the method body), we could simply write “return _array[index]” and there is no need to check if index is greater or lesser than Count, because that is specified in a “contract”. The implementation of Code Contract, requires that the contract is specified in the code. As a developer I would rather have this contract elsewhere (Like Spec#) or implemented in a way Eiffel uses it as part of the language. Now when we have looked at one Query, we can also look at one command, the Remove command (You can see the whole implementation of the Stack at the end of this blog post, where precondition is added to more queries and commands then what I’m going to show in this section). We can only Remove an item if the Count is greater than 0. So we can write a precondition that will require that Count must be greater than 0. public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .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; }   6. Write invariants to define unchanging properties of objects.   The last principle is about making sure the object are feeling great! This is done by using invariants. When using Code Contract we can specify invariants by adding a method with the attribute ContractInvariantMethod, the method must be private or public and can only contains calls to Contract.Invariant. To make sure the Stack feels great, the Stack must have 0 or more items, the Count can’t never be a negative value to make sure each command and queries can be used of the Stack. Here is our invariant for the Stack object: [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } .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; }   Note: The ObjectInvariant method will be called every time after a Query or Commands is called. Here is the full example using Code Contract:   public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } set { Contract.Requires(index >= 1); Contract.Requires(index <= Count); _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } //Is related to Count and this[] Query public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } //Creation commands public Stack(uint size) { Contract.Requires(size > 0); Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Requires(value != null); Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } } .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; } Summary By using Design By Contract we can make sure the users are using our code in a correct way, and we must also make sure the users will get the expected results when they uses our code. This can be done by specifying contracts. To make it easy to use Design By Contract, some principles may be good to follow like the separation of commands an queries. With .Net 4.0 we can use the Code Contract feature to specify contracts.

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  • What is a good method to use with multithreading to simulate this?

    - by user1504257
    I am writing a program in c++ in visual studio to be able to handle a line at a park. I have all of my customers in a line at the park and I want to be able to service them using multithreading with openmp. When I put the pragma and such in, I have multiple threads servicing the same customer at the same time for each and every customer I create, not what I want. I want for example, if I had two threads and four customers, that thread one to do customer one while thread 2 does customer 2. Then I would like thread 1 to do customer 3 and thread 2 customer 4 at the same time. I don't know if its possible or if there is a better way, but I need to use openmp. Thanks for your input.

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  • Codesample with bufferoverflow (gets method). Why does it not behave as expected?

    - by citronas
    This an extract from an c program that should demonstrate a bufferoverflow. void foo() { char arr[8]; printf(" enter bla bla bla"); gets(arr); printf(" you entered %s\n", arr); } The question was "How many input chars can a user maximal enter without a creating a buffer overflow" My initial answer was 8, because the char-array is 8 bytes long. Although I was pretty certain my answer was correct, I tried a higher amount of chars, and found that the limit of chars that I can enter, before I get a segmentation fault is 11. (Im running this on A VirtualBox Ubuntu) So my question is: Why is it possible to enter 11 chars into that 8 byte array?

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  • Which method should I use to give the perception the computer is thinking in programming?

    - by Roy
    I want to create a simple game like tic tac toe where the human user is playing against the computer. The computer function takes a couple of milliseconds to run but I would like to make the computer take 5 seconds to make a move. Which method should I use? 1) Create two memory threads. One for the computer and one for the human user. When the computer is taking 5 seconds to imitate thinking, the human user thread is paused for 5 seconds. 2) Disable input devices for 5 seconds using timer or dispatchertimer 3) Any better methods you can think of Thanks!

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  • What is the right method for parsing a blog post?

    - by Zedwal
    Hi guys, Need a guide line .... I am trying to write a personal blog. What is the standard structure for for input for the post. I am trying the format like: This is the simple text And I am [b] bold text[/b]. This is the code part: [code lang=java] public static void main (String args[]) { System.out.println("Hello World!"); } [/code] Is this the right way to store post in the database? And What is the right method to parse this kind of post? Shall I use regular expression to parse this or there is another standard for this. If the above mentioned format is not the right way for storage, then what it could be? Thanks

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  • How to find which method makes my iPhone app slow ?

    - by Stewart Hou
    Currently I am working on a production app. One function acts like the settings.app on iPhone. When the user click a cell of a tableView, as shown below http://www.penguintech.net/images/stackoverflow/1.png It will push another view, which includes a textfield to let user input something. However, on both simulator and device, after the app just loaded, the delay between clicking and showing the second view takes around 2 seconds. Then if user get back to previous view and click again, it will be no delay at all. To detect which method makes the delay, I put a NSLog() in every involved methods, but when I was inspecting the console while running the app, all NSLog() message showed in 0.1 seconds, and then still a delay on the app. Is there any other way to trace the performance footage of a app? The Instruments shows only CPU usage in Mac OS not in iPhone.

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  • Dependency Injection in ASP.NET MVC NerdDinner App using Ninject

    - by shiju
    In this post, I am applying Dependency Injection to the NerdDinner application using Ninject. The controllers of NerdDinner application have Dependency Injection enabled constructors. So we can apply Dependency Injection through constructor without change any existing code. A Dependency Injection framework injects the dependencies into a class when the dependencies are needed. Dependency Injection enables looser coupling between classes and their dependencies and provides better testability of an application and it removes the need for clients to know about their dependencies and how to create them. If you are not familiar with Dependency Injection and Inversion of Control (IoC), read Martin Fowler’s article Inversion of Control Containers and the Dependency Injection pattern. The Open Source Project NerDinner is a great resource for learning ASP.NET MVC.  A free eBook provides an end-to-end walkthrough of building NerdDinner.com application. The free eBook and the Open Source Nerddinner application are extremely useful if anyone is trying to lean ASP.NET MVC. The first release of  Nerddinner was as a sample for the first chapter of Professional ASP.NET MVC 1.0. Currently the application is updating to ASP.NET MVC 2 and you can get the latest source from the source code tab of Nerddinner at http://nerddinner.codeplex.com/SourceControl/list/changesets. I have taken the latest ASP.NET MVC 2 source code of the application and applied  Dependency Injection using Ninject and Ninject extension Ninject.Web.Mvc.Ninject &  Ninject.Web.MvcNinject is available at http://github.com/enkari/ninject and Ninject.Web.Mvc is available at http://github.com/enkari/ninject.web.mvcNinject is a lightweight and a great dependency injection framework for .NET.  Ninject is a great choice of dependency injection framework when building ASP.NET MVC applications. Ninject.Web.Mvc is an extension for ninject which providing integration with ASP.NET MVC.Controller constructors and dependencies of NerdDinner application Listing 1 – Constructor of DinnersController  public DinnersController(IDinnerRepository repository) {     dinnerRepository = repository; }  Listing 2 – Constrcutor of AccountControllerpublic AccountController(IFormsAuthentication formsAuth, IMembershipService service) {     FormsAuth = formsAuth ?? new FormsAuthenticationService();     MembershipService = service ?? new AccountMembershipService(); }  Listing 3 – Constructor of AccountMembership – Concrete class of IMembershipService public AccountMembershipService(MembershipProvider provider) {     _provider = provider ?? Membership.Provider; }    Dependencies of NerdDinnerDinnersController, RSVPController SearchController and ServicesController have a dependency with IDinnerRepositiry. The concrete implementation of IDinnerRepositiry is DinnerRepositiry. AccountController has dependencies with IFormsAuthentication and IMembershipService. The concrete implementation of IFormsAuthentication is FormsAuthenticationService and the concrete implementation of IMembershipService is AccountMembershipService. The AccountMembershipService has a dependency with ASP.NET Membership Provider. Dependency Injection in NerdDinner using NinjectThe below steps will configure Ninject to apply controller injection in NerdDinner application.Step 1 – Add reference for NinjectOpen the  NerdDinner application and add  reference to Ninject.dll and Ninject.Web.Mvc.dll. Both are available from http://github.com/enkari/ninject and http://github.com/enkari/ninject.web.mvcStep 2 – Extend HttpApplication with NinjectHttpApplication Ninject.Web.Mvc extension allows integration between the Ninject and ASP.NET MVC. For this, you have to extend your HttpApplication with NinjectHttpApplication. Open the Global.asax.cs and inherit your MVC application from  NinjectHttpApplication instead of HttpApplication.   public class MvcApplication : NinjectHttpApplication Then the Application_Start method should be replace with OnApplicationStarted method. Inside the OnApplicationStarted method, call the RegisterAllControllersIn() method.   protected override void OnApplicationStarted() {     AreaRegistration.RegisterAllAreas();     RegisterRoutes(RouteTable.Routes);     ViewEngines.Engines.Clear();     ViewEngines.Engines.Add(new MobileCapableWebFormViewEngine());     RegisterAllControllersIn(Assembly.GetExecutingAssembly()); }  The RegisterAllControllersIn method will enables to activating all controllers through Ninject in the assembly you have supplied .We are passing the current assembly as parameter for RegisterAllControllersIn() method. Now we can expose dependencies of controller constructors and properties to request injectionsStep 3 – Create Ninject ModulesWe can configure your dependency injection mapping information using Ninject Modules.Modules just need to implement the INinjectModule interface, but most should extend the NinjectModule class for simplicity. internal class ServiceModule : NinjectModule {     public override void Load()     {                    Bind<IFormsAuthentication>().To<FormsAuthenticationService>();         Bind<IMembershipService>().To<AccountMembershipService>();                  Bind<MembershipProvider>().ToConstant(Membership.Provider);         Bind<IDinnerRepository>().To<DinnerRepository>();     } } The above Binding inforamtion specified in the Load method tells the Ninject container that, to inject instance of DinnerRepositiry when there is a request for IDinnerRepositiry and  inject instance of FormsAuthenticationService when there is a request for IFormsAuthentication and inject instance of AccountMembershipService when there is a request for IMembershipService. The AccountMembershipService class has a dependency with ASP.NET Membership provider. So we configure that inject the instance of Membership Provider. When configuring the binding information, you can specify the object scope in you application.There are four built-in scopes available in Ninject:Transient  -  A new instance of the type will be created each time one is requested. (This is the default scope). Binding method is .InTransientScope()   Singleton - Only a single instance of the type will be created, and the same instance will be returned for each subsequent request. Binding method is .InSingletonScope()Thread -  One instance of the type will be created per thread. Binding method is .InThreadScope() Request -  One instance of the type will be created per web request, and will be destroyed when the request ends. Binding method is .InRequestScope() Step 4 – Configure the Ninject KernelOnce you create NinjectModule, you load them into a container called the kernel. To request an instance of a type from Ninject, you call the Get() extension method. We can configure the kernel, through the CreateKernel method in the Global.asax.cs. protected override IKernel CreateKernel() {     var modules = new INinjectModule[]     {         new ServiceModule()     };       return new StandardKernel(modules); } Here we are loading the Ninject Module (ServiceModule class created in the step 3)  onto the container called the kernel for performing dependency injection.Source CodeYou can download the source code from http://nerddinneraddons.codeplex.com. I just put the modified source code onto CodePlex repository. The repository will update with more add-ons for the NerdDinner application.

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  • Class-Level Model Validation with EF Code First and ASP.NET MVC 3

    - by ScottGu
    Earlier this week the data team released the CTP5 build of the new Entity Framework Code-First library.  In my blog post a few days ago I talked about a few of the improvements introduced with the new CTP5 build.  Automatic support for enforcing DataAnnotation validation attributes on models was one of the improvements I discussed.  It provides a pretty easy way to enable property-level validation logic within your model layer. You can apply validation attributes like [Required], [Range], and [RegularExpression] – all of which are built-into .NET 4 – to your model classes in order to enforce that the model properties are valid before they are persisted to a database.  You can also create your own custom validation attributes (like this cool [CreditCard] validator) and have them be automatically enforced by EF Code First as well.  This provides a really easy way to validate property values on your models.  I showed some code samples of this in action in my previous post. Class-Level Model Validation using IValidatableObject DataAnnotation attributes provides an easy way to validate individual property values on your model classes.  Several people have asked - “Does EF Code First also support a way to implement class-level validation methods on model objects, for validation rules than need to span multiple property values?”  It does – and one easy way you can enable this is by implementing the IValidatableObject interface on your model classes. IValidatableObject.Validate() Method Below is an example of using the IValidatableObject interface (which is built-into .NET 4 within the System.ComponentModel.DataAnnotations namespace) to implement two custom validation rules on a Product model class.  The two rules ensure that: New units can’t be ordered if the Product is in a discontinued state New units can’t be ordered if there are already more than 100 units in stock We will enforce these business rules by implementing the IValidatableObject interface on our Product class, and by implementing its Validate() method like so: The IValidatableObject.Validate() method can apply validation rules that span across multiple properties, and can yield back multiple validation errors. Each ValidationResult returned can supply both an error message as well as an optional list of property names that caused the violation (which is useful when displaying error messages within UI). Automatic Validation Enforcement EF Code-First (starting with CTP5) now automatically invokes the Validate() method when a model object that implements the IValidatableObject interface is saved.  You do not need to write any code to cause this to happen – this support is now enabled by default. This new support means that the below code – which violates one of our above business rules – will automatically throw an exception (and abort the transaction) when we call the “SaveChanges()” method on our Northwind DbContext: In addition to reactively handling validation exceptions, EF Code First also allows you to proactively check for validation errors.  Starting with CTP5, you can call the “GetValidationErrors()” method on the DbContext base class to retrieve a list of validation errors within the model objects you are working with.  GetValidationErrors() will return a list of all validation errors – regardless of whether they are generated via DataAnnotation attributes or by an IValidatableObject.Validate() implementation.  Below is an example of proactively using the GetValidationErrors() method to check (and handle) errors before trying to call SaveChanges(): ASP.NET MVC 3 and IValidatableObject ASP.NET MVC 2 included support for automatically honoring and enforcing DataAnnotation attributes on model objects that are used with ASP.NET MVC’s model binding infrastructure.  ASP.NET MVC 3 goes further and also honors the IValidatableObject interface.  This combined support for model validation makes it easy to display appropriate error messages within forms when validation errors occur.  To see this in action, let’s consider a simple Create form that allows users to create a new Product: We can implement the above Create functionality using a ProductsController class that has two “Create” action methods like below: The first Create() method implements a version of the /Products/Create URL that handles HTTP-GET requests - and displays the HTML form to fill-out.  The second Create() method implements a version of the /Products/Create URL that handles HTTP-POST requests - and which takes the posted form data, ensures that is is valid, and if it is valid saves it in the database.  If there are validation issues it redisplays the form with the posted values.  The razor view template of our “Create” view (which renders the form) looks like below: One of the nice things about the above Controller + View implementation is that we did not write any validation logic within it.  The validation logic and business rules are instead implemented entirely within our model layer, and the ProductsController simply checks whether it is valid (by calling the ModelState.IsValid helper method) to determine whether to try and save the changes or redisplay the form with errors. The Html.ValidationMessageFor() helper method calls within our view simply display the error messages our Product model’s DataAnnotations and IValidatableObject.Validate() method returned.  We can see the above scenario in action by filling out invalid data within the form and attempting to submit it: Notice above how when we hit the “Create” button we got an error message.  This was because we ticked the “Discontinued” checkbox while also entering a value for the UnitsOnOrder (and so violated one of our business rules).  You might ask – how did ASP.NET MVC know to highlight and display the error message next to the UnitsOnOrder textbox?  It did this because ASP.NET MVC 3 now honors the IValidatableObject interface when performing model binding, and will retrieve the error messages from validation failures with it. The business rule within our Product model class indicated that the “UnitsOnOrder” property should be highlighted when the business rule we hit was violated: Our Html.ValidationMessageFor() helper method knew to display the business rule error message (next to the UnitsOnOrder edit box) because of the above property name hint we supplied: Keeping things DRY ASP.NET MVC and EF Code First enables you to keep your validation and business rules in one place (within your model layer), and avoid having it creep into your Controllers and Views.  Keeping the validation logic in the model layer helps ensure that you do not duplicate validation/business logic as you add more Controllers and Views to your application.  It allows you to quickly change your business rules/validation logic in one single place (within your model layer) – and have all controllers/views across your application immediately reflect it.  This help keep your application code clean and easily maintainable, and makes it much easier to evolve and update your application in the future. Summary EF Code First (starting with CTP5) now has built-in support for both DataAnnotations and the IValidatableObject interface.  This allows you to easily add validation and business rules to your models, and have EF automatically ensure that they are enforced anytime someone tries to persist changes of them to a database.  ASP.NET MVC 3 also now supports both DataAnnotations and IValidatableObject as well, which makes it even easier to use them with your EF Code First model layer – and then have the controllers/views within your web layer automatically honor and support them as well.  This makes it easy to build clean and highly maintainable applications. You don’t have to use DataAnnotations or IValidatableObject to perform your validation/business logic.  You can always roll your own custom validation architecture and/or use other more advanced validation frameworks/patterns if you want.  But for a lot of applications this built-in support will probably be sufficient – and provide a highly productive way to build solutions. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • Handling HTTP 404 Error in ASP.NET Web API

    - by imran_ku07
            Introduction:                     Building modern HTTP/RESTful/RPC services has become very easy with the new ASP.NET Web API framework. Using ASP.NET Web API framework, you can create HTTP services which can be accessed from browsers, machines, mobile devices and other clients. Developing HTTP services is now become more easy for ASP.NET MVC developer becasue ASP.NET Web API is now included in ASP.NET MVC. In addition to developing HTTP services, it is also important to return meaningful response to client if a resource(uri) not found(HTTP 404) for a reason(for example, mistyped resource uri). It is also important to make this response centralized so you can configure all of 'HTTP 404 Not Found' resource at one place. In this article, I will show you how to handle 'HTTP 404 Not Found' at one place.         Description:                     Let's say that you are developing a HTTP RESTful application using ASP.NET Web API framework. In this application you need to handle HTTP 404 errors in a centralized location. From ASP.NET Web API point of you, you need to handle these situations, No route matched. Route is matched but no {controller} has been found on route. No type with {controller} name has been found. No matching action method found in the selected controller due to no action method start with the request HTTP method verb or no action method with IActionHttpMethodProviderRoute implemented attribute found or no method with {action} name found or no method with the matching {action} name found.                                          Now, let create a ErrorController with Handle404 action method. This action method will be used in all of the above cases for sending HTTP 404 response message to the client.  public class ErrorController : ApiController { [HttpGet, HttpPost, HttpPut, HttpDelete, HttpHead, HttpOptions, AcceptVerbs("PATCH")] public HttpResponseMessage Handle404() { var responseMessage = new HttpResponseMessage(HttpStatusCode.NotFound); responseMessage.ReasonPhrase = "The requested resource is not found"; return responseMessage; } }                     You can easily change the above action method to send some other specific HTTP 404 error response. If a client of your HTTP service send a request to a resource(uri) and no route matched with this uri on server then you can route the request to the above Handle404 method using a custom route. Put this route at the very bottom of route configuration,  routes.MapHttpRoute( name: "Error404", routeTemplate: "{*url}", defaults: new { controller = "Error", action = "Handle404" } );                     Now you need handle the case when there is no {controller} in the matching route or when there is no type with {controller} name found. You can easily handle this case and route the request to the above Handle404 method using a custom IHttpControllerSelector. Here is the definition of a custom IHttpControllerSelector, public class HttpNotFoundAwareDefaultHttpControllerSelector : DefaultHttpControllerSelector { public HttpNotFoundAwareDefaultHttpControllerSelector(HttpConfiguration configuration) : base(configuration) { } public override HttpControllerDescriptor SelectController(HttpRequestMessage request) { HttpControllerDescriptor decriptor = null; try { decriptor = base.SelectController(request); } catch (HttpResponseException ex) { var code = ex.Response.StatusCode; if (code != HttpStatusCode.NotFound) throw; var routeValues = request.GetRouteData().Values; routeValues["controller"] = "Error"; routeValues["action"] = "Handle404"; decriptor = base.SelectController(request); } return decriptor; } }                     Next, it is also required to pass the request to the above Handle404 method if no matching action method found in the selected controller due to the reason discussed above. This situation can also be easily handled through a custom IHttpActionSelector. Here is the source of custom IHttpActionSelector,  public class HttpNotFoundAwareControllerActionSelector : ApiControllerActionSelector { public HttpNotFoundAwareControllerActionSelector() { } public override HttpActionDescriptor SelectAction(HttpControllerContext controllerContext) { HttpActionDescriptor decriptor = null; try { decriptor = base.SelectAction(controllerContext); } catch (HttpResponseException ex) { var code = ex.Response.StatusCode; if (code != HttpStatusCode.NotFound && code != HttpStatusCode.MethodNotAllowed) throw; var routeData = controllerContext.RouteData; routeData.Values["action"] = "Handle404"; IHttpController httpController = new ErrorController(); controllerContext.Controller = httpController; controllerContext.ControllerDescriptor = new HttpControllerDescriptor(controllerContext.Configuration, "Error", httpController.GetType()); decriptor = base.SelectAction(controllerContext); } return decriptor; } }                     Finally, we need to register the custom IHttpControllerSelector and IHttpActionSelector. Open global.asax.cs file and add these lines,  configuration.Services.Replace(typeof(IHttpControllerSelector), new HttpNotFoundAwareDefaultHttpControllerSelector(configuration)); configuration.Services.Replace(typeof(IHttpActionSelector), new HttpNotFoundAwareControllerActionSelector());         Summary:                       In addition to building an application for HTTP services, it is also important to send meaningful centralized information in response when something goes wrong, for example 'HTTP 404 Not Found' error.  In this article, I showed you how to handle 'HTTP 404 Not Found' error in a centralized location. Hopefully you will enjoy this article too.

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  • C# Extension Methods - To Extend or Not To Extend...

    - by James Michael Hare
    I've been thinking a lot about extension methods lately, and I must admit I both love them and hate them. They are a lot like sugar, they taste so nice and sweet, but they'll rot your teeth if you eat them too much.   I can't deny that they aren't useful and very handy. One of the major components of the Shared Component library where I work is a set of useful extension methods. But, I also can't deny that they tend to be overused and abused to willy-nilly extend every living type.   So what constitutes a good extension method? Obviously, you can write an extension method for nearly anything whether it is a good idea or not. Many times, in fact, an idea seems like a good extension method but in retrospect really doesn't fit.   So what's the litmus test? To me, an extension method should be like in the movies when a person runs into their twin, separated at birth. You just know you're related. Obviously, that's hard to quantify, so let's try to put a few rules-of-thumb around them.   A good extension method should:     Apply to any possible instance of the type it extends.     Simplify logic and improve readability/maintainability.     Apply to the most specific type or interface applicable.     Be isolated in a namespace so that it does not pollute IntelliSense.     So let's look at a few examples in relation to these rules.   The first rule, to me, is the most important of all. Once again, it bears repeating, a good extension method should apply to all possible instances of the type it extends. It should feel like the long lost relative that should have been included in the original class but somehow was missing from the family tree.    Take this nifty little int extension, I saw this once in a blog and at first I really thought it was pretty cool, but then I started noticing a code smell I couldn't quite put my finger on. So let's look:       public static class IntExtensinos     {         public static int Seconds(int num)         {             return num * 1000;         }           public static int Minutes(int num)         {             return num * 60000;         }     }     This is so you could do things like:       ...     Thread.Sleep(5.Seconds());     ...     proxy.Timeout = 1.Minutes();     ...     Awww, you say, that's cute! Well, that's the problem, it's kitschy and it doesn't always apply (and incidentally you could achieve the same thing with TimeStamp.FromSeconds(5)). It's syntactical candy that looks cool, but tends to rot and pollute the code. It would allow things like:       total += numberOfTodaysOrders.Seconds();     which makes no sense and should never be allowed. The problem is you're applying an extension method to a logical domain, not a type domain. That is, the extension method Seconds() doesn't really apply to ALL ints, it applies to ints that are representative of time that you want to convert to milliseconds.    Do you see what I mean? The two problems, in a nutshell, are that a) Seconds() called off a non-time value makes no sense and b) calling Seconds() off something to pass to something that does not take milliseconds will be off by a factor of 1000 or worse.   Thus, in my mind, you should only ever have an extension method that applies to the whole domain of that type.   For example, this is one of my personal favorites:       public static bool IsBetween<T>(this T value, T low, T high)         where T : IComparable<T>     {         return value.CompareTo(low) >= 0 && value.CompareTo(high) <= 0;     }   This allows you to check if any IComparable<T> is within an upper and lower bound. Think of how many times you type something like:       if (response.Employee.Address.YearsAt >= 2         && response.Employee.Address.YearsAt <= 10)     {     ...     }     Now, you can instead type:       if(response.Employee.Address.YearsAt.IsBetween(2, 10))     {     ...     }     Note that this applies to all IComparable<T> -- that's ints, chars, strings, DateTime, etc -- and does not depend on any logical domain. In addition, it satisfies the second point and actually makes the code more readable and maintainable.   Let's look at the third point. In it we said that an extension method should fit the most specific interface or type possible. Now, I'm not saying if you have something that applies to enumerables, you create an extension for List, Array, Dictionary, etc (though you may have reasons for doing so), but that you should beware of making things TOO general.   For example, let's say we had an extension method like this:       public static T ConvertTo<T>(this object value)     {         return (T)Convert.ChangeType(value, typeof(T));     }         This lets you do more fluent conversions like:       double d = "5.0".ConvertTo<double>();     However, if you dig into Reflector (LOVE that tool) you will see that if the type you are calling on does not implement IConvertible, what you convert to MUST be the exact type or it will throw an InvalidCastException. Now this may or may not be what you want in this situation, and I leave that up to you. Things like this would fail:       object value = new Employee();     ...     // class cast exception because typeof(IEmployee) != typeof(Employee)     IEmployee emp = value.ConvertTo<IEmployee>();       Yes, that's a downfall of working with Convertible in general, but if you wanted your fluent interface to be more type-safe so that ConvertTo were only callable on IConvertibles (and let casting be a manual task), you could easily make it:         public static T ConvertTo<T>(this IConvertible value)     {         return (T)Convert.ChangeType(value, typeof(T));     }         This is what I mean by choosing the best type to extend. Consider that if we used the previous (object) version, every time we typed a dot ('.') on an instance we'd pull up ConvertTo() whether it was applicable or not. By filtering our extension method down to only valid types (those that implement IConvertible) we greatly reduce our IntelliSense pollution and apply a good level of compile-time correctness.   Now my fourth rule is just my general rule-of-thumb. Obviously, you can make extension methods as in-your-face as you want. I included all mine in my work libraries in its own sub-namespace, something akin to:       namespace Shared.Core.Extensions { ... }     This is in a library called Shared.Core, so just referencing the Core library doesn't pollute your IntelliSense, you have to actually do a using on Shared.Core.Extensions to bring the methods in. This is very similar to the way Microsoft puts its extension methods in System.Linq. This way, if you want 'em, you use the appropriate namespace. If you don't want 'em, they won't pollute your namespace.   To really make this work, however, that namespace should only include extension methods and subordinate types those extensions themselves may use. If you plant other useful classes in those namespaces, once a user includes it, they get all the extensions too.   Also, just as a personal preference, extension methods that aren't simply syntactical shortcuts, I like to put in a static utility class and then have extension methods for syntactical candy. For instance, I think it imaginable that any object could be converted to XML:       namespace Shared.Core     {         // A collection of XML Utility classes         public static class XmlUtility         {             ...             // Serialize an object into an xml string             public static string ToXml(object input)             {                 var xs = new XmlSerializer(input.GetType());                   // use new UTF8Encoding here, not Encoding.UTF8. The later includes                 // the BOM which screws up subsequent reads, the former does not.                 using (var memoryStream = new MemoryStream())                 using (var xmlTextWriter = new XmlTextWriter(memoryStream, new UTF8Encoding()))                 {                     xs.Serialize(xmlTextWriter, input);                     return Encoding.UTF8.GetString(memoryStream.ToArray());                 }             }             ...         }     }   I also wanted to be able to call this from an object like:       value.ToXml();     But here's the problem, if i made this an extension method from the start with that one little keyword "this", it would pop into IntelliSense for all objects which could be very polluting. Instead, I put the logic into a utility class so that users have the choice of whether or not they want to use it as just a class and not pollute IntelliSense, then in my extensions namespace, I add the syntactical candy:       namespace Shared.Core.Extensions     {         public static class XmlExtensions         {             public static string ToXml(this object value)             {                 return XmlUtility.ToXml(value);             }         }     }   So now it's the best of both worlds. On one hand, they can use the utility class if they don't want to pollute IntelliSense, and on the other hand they can include the Extensions namespace and use as an extension if they want. The neat thing is it also adheres to the Single Responsibility Principle. The XmlUtility is responsible for converting objects to XML, and the XmlExtensions is responsible for extending object's interface for ToXml().

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  • Using Sitecore RenderingContext Parameters as MVC controller action arguments

    - by Kyle Burns
    I have been working with the Technical Preview of Sitecore 6.6 on a project and have been for the most part happy with the way that Sitecore (which truly is an MVC implementation unto itself) has been expanded to support ASP.NET MVC. That said, getting up to speed with the combined platform has not been entirely without stumbles and today I want to share one area where Sitecore could have really made things shine from the "it just works" perspective. A couple days ago I was asked by a colleague about the usage of the "Parameters" field that is defined on Sitecore's Controller Rendering data template. Based on the standard way that Sitecore handles a field named Parameters, I was able to deduce that the field expected key/value pairs separated by the "&" character, but beyond that I wasn't sure and didn't see anything from a documentation perspective to guide me, so it was time to dig and find out where the data in the field was made available. My first thought was that it would be really nice if Sitecore handled the parameters in this field consistently with the way that ASP.NET MVC handles the various parameter collections on the HttpRequest object and automatically maps them to parameters of the action method executing. Being the hopeful sort, I configured a name/value pair on one of my renderings, added a parameter with matching name to the controller action and fired up the bugger to see... that the parameter was not populated. Having established that the field's value was not going to be presented to me the way that I had hoped it would, the next assumption that I would work on was that Sitecore would handle this field similar to how they handle other similar data and would plug it into some ambient object that I could reference from within the controller method. After a considerable amount of guessing, testing, and cracking code open with Redgate's Reflector (a must-have companion to Sitecore documentation), I found that the most direct way to access the parameter was through the ambient RenderingContext object using code similar to: string myArgument = string.Empty; var rc = Sitecore.Mvc.Presentation.RenderingContext.CurrentOrNull; if (rc != null) {     var parms = rc.Rendering.Parameters;     myArgument = parms["myArgument"]; } At this point, we know how this field is used out of the box from Sitecore and can provide information from Sitecore's Content Editor that will be available when the controller action is executing, but it feels a little dirty. In order to properly test the action method I would have to do a lot of setup work and possible use an isolation framework such as Pex and Moles to get at a value that my action method is dependent upon. Notice I said that my method is dependent upon the value but in order to meet that dependency I've accepted another dependency upon Sitecore's RenderingContext.  I'm a big believer in, when possible, ensuring that any piece of code explicitly advertises dependencies using the method signature, so I found myself still wanting this to work the same as if the parameters were in the request route, querystring, or form by being able to add a myArgument parameter to the action method and have this parameter populated by the framework. Lucky for us, the ASP.NET MVC framework is extremely flexible and provides some easy to grok and use extensibility points. ASP.NET MVC is able to provide information from the request as input parameters to controller actions because it uses objects which implement an interface called IValueProvider and have been registered to service the application. The most basic statement of responsibility for an IValueProvider implementation is "I know about some data which is indexed by key. If you hand me the key for a piece of data that I know about I give you that data". When preparing to invoke a controller action, the framework queries registered IValueProvider implementations with the name of each method argument to see if the ValueProvider can supply a value for the parameter. (the rest of this post will assume you're working along and make a lot more sense if you do) Let's pull Sitecore out of the equation for a second to simplify things and create an extremely simple IValueProvider implementation. For this example, I first create a new ASP.NET MVC3 project in Visual Studio, selecting "Internet Application" and otherwise taking defaults (I'm assuming that anyone reading this far in the post either already knows how to do this or will need to take a quick run through one of the many available basic MVC tutorials such as the MVC Music Store). Once the new project is created, go to the Index action of HomeController.  This action sets a Message property on the ViewBag to "Welcome to ASP.NET MVC!" and invokes the View, which has been coded to display the Message. For our example, we will remove the hard coded message from this controller (although we'll leave it just as hard coded somewhere else - this is sample code). For the first step in our exercise, add a string parameter to the Index action method called welcomeMessage and use the value of this argument to set the ViewBag.Message property. The updated Index action should look like: public ActionResult Index(string welcomeMessage) {     ViewBag.Message = welcomeMessage;     return View(); } This represents the entirety of the change that you will make to either the controller or view.  If you run the application now, the home page will display and no message will be presented to the user because no value was supplied to the Action method. Let's now write a ValueProvider to ensure this parameter gets populated. We'll start by creating a new class called StaticValueProvider. When the class is created, we'll update the using statements to ensure that they include the following: using System.Collections.Specialized; using System.Globalization; using System.Web.Mvc; With the appropriate using statements in place, we'll update the StaticValueProvider class to implement the IValueProvider interface. The System.Web.Mvc library already contains a pretty flexible dictionary-like implementation called NameValueCollectionValueProvider, so we'll just wrap that and let it do most of the real work for us. The completed class looks like: public class StaticValueProvider : IValueProvider {     private NameValueCollectionValueProvider _wrappedProvider;     public StaticValueProvider(ControllerContext controllerContext)     {         var parameters = new NameValueCollection();         parameters.Add("welcomeMessage", "Hello from the value provider!");         _wrappedProvider = new NameValueCollectionValueProvider(parameters, CultureInfo.InvariantCulture);     }     public bool ContainsPrefix(string prefix)     {         return _wrappedProvider.ContainsPrefix(prefix);     }     public ValueProviderResult GetValue(string key)     {         return _wrappedProvider.GetValue(key);     } } Notice that the only entry in the collection matches the name of the argument to our HomeController's Index action.  This is the important "secret sauce" that will make things work. We've got our new value provider now, but that's not quite enough to be finished. Mvc obtains IValueProvider instances using factories that are registered when the application starts up. These factories extend the abstract ValueProviderFactory class by initializing and returning the appropriate implementation of IValueProvider from the GetValueProvider method. While I wouldn't do so in production code, for the sake of this example, I'm going to add the following class definition within the StaticValueProvider.cs source file: public class StaticValueProviderFactory : ValueProviderFactory {     public override IValueProvider GetValueProvider(ControllerContext controllerContext)     {         return new StaticValueProvider(controllerContext);     } } Now that we have a factory, we can register it by adding the following line to the end of the Application_Start method in Global.asax.cs: ValueProviderFactories.Factories.Add(new StaticValueProviderFactory()); If you've done everything right to this point, you should be able to run the application and be presented with the home page reading "Hello from the value provider!". Now that you have the basics of the IValueProvider down, you have everything you need to enhance your Sitecore MVC implementation by adding an IValueProvider that exposes values from the ambient RenderingContext's Parameters property. I'll provide the code for the IValueProvider implementation (which should look VERY familiar) and you can use the work we've already done as a reference to create and register the factory: public class RenderingContextValueProvider : IValueProvider {     private NameValueCollectionValueProvider _wrappedProvider = null;     public RenderingContextValueProvider(ControllerContext controllerContext)     {         var collection = new NameValueCollection();         var rc = RenderingContext.CurrentOrNull;         if (rc != null && rc.Rendering != null)         {             foreach(var parameter in rc.Rendering.Parameters)             {                 collection.Add(parameter.Key, parameter.Value);             }         }         _wrappedProvider = new NameValueCollectionValueProvider(collection, CultureInfo.InvariantCulture);         }     public bool ContainsPrefix(string prefix)     {         return _wrappedProvider.ContainsPrefix(prefix);     }     public ValueProviderResult GetValue(string key)     {         return _wrappedProvider.GetValue(key);     } } In this post I've discussed the MVC IValueProvider used to map data to controller action method arguments and how this can be integrated into your Sitecore 6.6 MVC solution.

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  • We've completed the first iteration

    - by CliveT
    There are a lot of features in C# that are implemented by the compiler and not by the underlying platform. One such feature is a lambda expression. Since local variables cannot be accessed once the current method activation finishes, the compiler has to go out of its way to generate a new class which acts as a home for any variable whose lifetime needs to be extended past the activation of the procedure. Take the following example:     Random generator = new Random();     Func func = () = generator.Next(10); In this case, the compiler generates a new class called c_DisplayClass1 which is marked with the CompilerGenerated attribute. [CompilerGenerated] private sealed class c__DisplayClass1 {     // Fields     public Random generator;     // Methods     public int b__0()     {         return this.generator.Next(10);     } } Two quick comments on this: (i)    A display was the means that compilers for languages like Algol recorded the various lexical contours of the nested procedure activations on the stack. I imagine that this is what has led to the name. (ii)    It is a shame that the same attribute is used to mark all compiler generated classes as it makes it hard to figure out what they are being used for. Indeed, you could imagine optimisations that the runtime could perform if it knew that classes corresponded to certain high level concepts. We can see that the local variable generator has been turned into a field in the class, and the body of the lambda expression has been turned into a method of the new class. The code that builds the Func object simply constructs an instance of this class and initialises the fields to their initial values.     c__DisplayClass1 class2 = new c__DisplayClass1();     class2.generator = new Random();     Func func = new Func(class2.b__0); Reflector already contains code to spot this pattern of code and reproduce the form containing the lambda expression, so this is example is correctly decompiled. The use of compiler generated code is even more spectacular in the case of iterators. C# introduced the idea of a method that could automatically store its state between calls, so that it can pick up where it left off. The code can express the logical flow with yield return and yield break denoting places where the method should return a particular value and be prepared to resume.         {             yield return 1;             yield return 2;             yield return 3;         } Of course, there was already a .NET pattern for expressing the idea of returning a sequence of values with the computation proceeding lazily (in the sense that the work for the next value is executed on demand). This is expressed by the IEnumerable interface with its Current property for fetching the current value and the MoveNext method for forcing the computation of the next value. The sequence is terminated when this method returns false. The C# compiler links these two ideas together so that an IEnumerator returning method using the yield keyword causes the compiler to produce the implementation of an Iterator. Take the following piece of code.         IEnumerable GetItems()         {             yield return 1;             yield return 2;             yield return 3;         } The compiler implements this by defining a new class that implements a state machine. This has an integer state that records which yield point we should go to if we are resumed. It also has a field that records the Current value of the enumerator and a field for recording the thread. This latter value is used for optimising the creation of iterator instances. [CompilerGenerated] private sealed class d__0 : IEnumerable, IEnumerable, IEnumerator, IEnumerator, IDisposable {     // Fields     private int 1__state;     private int 2__current;     public Program 4__this;     private int l__initialThreadId; The body gets converted into the code to construct and initialize this new class. private IEnumerable GetItems() {     d__0 d__ = new d__0(-2);     d__.4__this = this;     return d__; } When the class is constructed we set the state, which was passed through as -2 and the current thread. public d__0(int 1__state) {     this.1__state = 1__state;     this.l__initialThreadId = Thread.CurrentThread.ManagedThreadId; } The state needs to be set to 0 to represent a valid enumerator and this is done in the GetEnumerator method which optimises for the usual case where the returned enumerator is only used once. IEnumerator IEnumerable.GetEnumerator() {     if ((Thread.CurrentThread.ManagedThreadId == this.l__initialThreadId)               && (this.1__state == -2))     {         this.1__state = 0;         return this;     } The state machine itself is implemented inside the MoveNext method. private bool MoveNext() {     switch (this.1__state)     {         case 0:             this.1__state = -1;             this.2__current = 1;             this.1__state = 1;             return true;         case 1:             this.1__state = -1;             this.2__current = 2;             this.1__state = 2;             return true;         case 2:             this.1__state = -1;             this.2__current = 3;             this.1__state = 3;             return true;         case 3:             this.1__state = -1;             break;     }     return false; } At each stage, the current value of the state is used to determine how far we got, and then we generate the next value which we return after recording the next state. Finally we return false from the MoveNext to signify the end of the sequence. Of course, that example was really simple. The original method body didn't have any local variables. Any local variables need to live between the calls to MoveNext and so they need to be transformed into fields in much the same way that we did in the case of the lambda expression. More complicated MoveNext methods are required to deal with resources that need to be disposed when the iterator finishes, and sometimes the compiler uses a temporary variable to hold the return value. Why all of this explanation? We've implemented the de-compilation of iterators in the current EAP version of Reflector (7). This contrasts with previous version where all you could do was look at the MoveNext method and try to figure out the control flow. There's a fair amount of things we have to do. We have to spot the use of a CompilerGenerated class which implements the Enumerator pattern. We need to go to the class and figure out the fields corresponding to the local variables. We then need to go to the MoveNext method and try to break it into the various possible states and spot the state transitions. We can then take these pieces and put them back together into an object model that uses yield return to show the transition points. After that Reflector can carry on optimising using its usual optimisations. The pattern matching is currently a little too sensitive to changes in the code generation, and we only do a limited analysis of the MoveNext method to determine use of the compiler generated fields. In some ways, it is a pity that iterators are compiled away and there is no metadata that reflects the original intent. Without it, we are always going to dependent on our knowledge of the compiler's implementation. For example, we have noticed that the Async CTP changes the way that iterators are code generated, so we'll have to do some more work to support that. However, with that warning in place, we seem to do a reasonable job of decompiling the iterators that are built into the framework. Hopefully, the EAP will give us a chance to find examples where we don't spot the pattern correctly or regenerate the wrong code, and we can improve things. Please give it a go, and report any problems.

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  • An Introduction to jQuery Templates

    - by Stephen Walther
    The goal of this blog entry is to provide you with enough information to start working with jQuery Templates. jQuery Templates enable you to display and manipulate data in the browser. For example, you can use jQuery Templates to format and display a set of database records that you have retrieved with an Ajax call. jQuery Templates supports a number of powerful features such as template tags, template composition, and wrapped templates. I’ll concentrate on the features that I think that you will find most useful. In order to focus on the jQuery Templates feature itself, this blog entry is server technology agnostic. All the samples use HTML pages instead of ASP.NET pages. In a future blog entry, I’ll focus on using jQuery Templates with ASP.NET Web Forms and ASP.NET MVC (You can do some pretty powerful things when jQuery Templates are used on the client and ASP.NET is used on the server). Introduction to jQuery Templates The jQuery Templates plugin was developed by the Microsoft ASP.NET team in collaboration with the open-source jQuery team. While working at Microsoft, I wrote the original proposal for jQuery Templates, Dave Reed wrote the original code, and Boris Moore wrote the final code. The jQuery team – especially John Resig – was very involved in each step of the process. Both the jQuery community and ASP.NET communities were very active in providing feedback. jQuery Templates will be included in the jQuery core library (the jQuery.js library) when jQuery 1.5 is released. Until jQuery 1.5 is released, you can download the jQuery Templates plugin from the jQuery Source Code Repository or you can use jQuery Templates directly from the ASP.NET CDN. The documentation for jQuery Templates is already included with the official jQuery documentation at http://api.jQuery.com. The main entry for jQuery templates is located under the topic plugins/templates. A Basic Sample of jQuery Templates Let’s start with a really simple sample of using jQuery Templates. We’ll use the plugin to display a list of books stored in a JavaScript array. Here’s the complete code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html > <head> <title>Intro</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg" }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg" }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg" }, ]; // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html> When you open this page in a browser, a list of books is displayed: There are several things going on in this page which require explanation. First, notice that the page uses both the jQuery 1.4.4 and jQuery Templates libraries. Both libraries are retrieved from the ASP.NET CDN: <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> You can use the ASP.NET CDN for free (even for production websites). You can learn more about the files included on the ASP.NET CDN by visiting the ASP.NET CDN documentation page. Second, you should notice that the actual template is included in a script tag with a special MIME type: <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> This template is displayed for each of the books rendered by the template. The template displays a book picture, title, and price. Notice that the SCRIPT tag which wraps the template has a MIME type of text/x-jQuery-tmpl. Why is the template wrapped in a SCRIPT tag and why the strange MIME type? When a browser encounters a SCRIPT tag with an unknown MIME type, it ignores the content of the tag. This is the behavior that you want with a template. You don’t want a browser to attempt to parse the contents of a template because this might cause side effects. For example, the template above includes an <img> tag with a src attribute that points at “BookPictures/${picture}”. You don’t want the browser to attempt to load an image at the URL “BookPictures/${picture}”. Instead, you want to prevent the browser from processing the IMG tag until the ${picture} expression is replaced by with the actual name of an image by the jQuery Templates plugin. If you are not worried about browser side-effects then you can wrap a template inside any HTML tag that you please. For example, the following DIV tag would also work with the jQuery Templates plugin: <div id="bookTemplate" style="display:none"> <div> <h2>${title}</h2> price: ${formatPrice(price)} </div> </div> Notice that the DIV tag includes a style=”display:none” attribute to prevent the template from being displayed until the template is parsed by the jQuery Templates plugin. Third, notice that the expression ${…} is used to display the value of a JavaScript expression within a template. For example, the expression ${title} is used to display the value of the book title property. You can use any JavaScript function that you please within the ${…} expression. For example, in the template above, the book price is formatted with the help of the custom JavaScript formatPrice() function which is defined lower in the page. Fourth, and finally, the template is rendered with the help of the tmpl() method. The following statement selects the bookTemplate and renders an array of books using the bookTemplate. The results are appended to a DIV element named bookContainer by using the standard jQuery appendTo() method. $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); Using Template Tags Within a template, you can use any of the following template tags. {{tmpl}} – Used for template composition. See the section below. {{wrap}} – Used for wrapped templates. See the section below. {{each}} – Used to iterate through a collection. {{if}} – Used to conditionally display template content. {{else}} – Used with {{if}} to conditionally display template content. {{html}} – Used to display the value of an HTML expression without encoding the value. Using ${…} or {{= }} performs HTML encoding automatically. {{= }}-- Used in exactly the same way as ${…}. {{! }} – Used for displaying comments. The contents of a {{!...}} tag are ignored. For example, imagine that you want to display a list of blog entries. Each blog entry could, possibly, have an associated list of categories. The following page illustrates how you can use the { if}} and {{each}} template tags to conditionally display categories for each blog entry:   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>each</title> <link href="1_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="blogPostContainer"></div> <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> var blogPosts = [ { postTitle: "How to fix a sink plunger in 5 minutes", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna.", categories: ["HowTo", "Sinks", "Plumbing"] }, { postTitle: "How to remove a broken lightbulb", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna.", categories: ["HowTo", "Lightbulbs", "Electricity"] }, { postTitle: "New associate website", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna." } ]; // Render the blog posts $("#blogPostTemplate").tmpl(blogPosts).appendTo("#blogPostContainer"); </script> </body> </html> When this page is opened in a web browser, the following list of blog posts and categories is displayed: Notice that the first and second blog entries have associated categories but the third blog entry does not. The third blog entry is “Uncategorized”. The template used to render the blog entries and categories looks like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script> Notice the special expression $value used within the {{each}} template tag. You can use $value to display the value of the current template item. In this case, $value is used to display the value of each category in the collection of categories. Template Composition When building a fancy page, you might want to build a template out of multiple templates. In other words, you might want to take advantage of template composition. For example, imagine that you want to display a list of products. Some of the products are being sold at their normal price and some of the products are on sale. In that case, you might want to use two different templates for displaying a product: a productTemplate and a productOnSaleTemplate. The following page illustrates how you can use the {{tmpl}} tag to build a template from multiple templates:   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Composition</title> <link href="2_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContainer"> <h1>Products</h1> <div id="productListContainer"></div> <!-- Show list of products using composition --> <script id="productListTemplate" type="text/x-jQuery-tmpl"> <div> {{if onSale}} {{tmpl "#productOnSaleTemplate"}} {{else}} {{tmpl "#productTemplate"}} {{/if}} </div> </script> <!-- Show product --> <script id="productTemplate" type="text/x-jQuery-tmpl"> ${name} </script> <!-- Show product on sale --> <script id="productOnSaleTemplate" type="text/x-jQuery-tmpl"> <b>${name}</b> <img src="images/on_sale.png" alt="On Sale" /> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> var products = [ { name: "Laptop", onSale: false }, { name: "Apples", onSale: true }, { name: "Comb", onSale: false } ]; $("#productListTemplate").tmpl(products).appendTo("#productListContainer"); </script> </div> </body> </html>   In the page above, the main template used to display the list of products looks like this: <script id="productListTemplate" type="text/x-jQuery-tmpl"> <div> {{if onSale}} {{tmpl "#productOnSaleTemplate"}} {{else}} {{tmpl "#productTemplate"}} {{/if}} </div> </script>   If a product is on sale then the product is displayed with the productOnSaleTemplate (which includes an on sale image): <script id="productOnSaleTemplate" type="text/x-jQuery-tmpl"> <b>${name}</b> <img src="images/on_sale.png" alt="On Sale" /> </script>   Otherwise, the product is displayed with the normal productTemplate (which does not include the on sale image): <script id="productTemplate" type="text/x-jQuery-tmpl"> ${name} </script>   You can pass a parameter to the {{tmpl}} tag. The parameter becomes the data passed to the template rendered by the {{tmpl}} tag. For example, in the previous section, we used the {{each}} template tag to display a list of categories for each blog entry like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script>   Another way to create this template is to use template composition like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{tmpl(categories) "#categoryTemplate"}} {{else}} Uncategorized {{/if}} </script> <script id="categoryTemplate" type="text/x-jQuery-tmpl"> <i>${$data}</i> &nbsp; </script>   Using the {{each}} tag or {{tmpl}} tag is largely a matter of personal preference. Wrapped Templates The {{wrap}} template tag enables you to take a chunk of HTML and transform the HTML into another chunk of HTML (think easy XSLT). When you use the {{wrap}} tag, you work with two templates. The first template contains the HTML being transformed and the second template includes the filter expressions for transforming the HTML. For example, you can use the {{wrap}} template tag to transform a chunk of HTML into an interactive tab strip: When you click any of the tabs, you see the corresponding content. This tab strip was created with the following page: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Wrapped Templates</title> <style type="text/css"> body { font-family: Arial; background-color:black; } .tabs div { display:inline-block; border-bottom: 1px solid black; padding:4px; background-color:gray; cursor:pointer; } .tabs div.tabState_true { background-color:white; border-bottom:1px solid white; } .tabBody { border-top:1px solid white; padding:10px; background-color:white; min-height:400px; width:400px; } </style> </head> <body> <div id="tabsView"></div> <script id="tabsContent" type="text/x-jquery-tmpl"> {{wrap "#tabsWrap"}} <h3>Tab 1</h3> <div> Content of tab 1. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 2</h3> <div> Content of tab 2. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 3</h3> <div> Content of tab 3. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> {{/wrap}} </script> <script id="tabsWrap" type="text/x-jquery-tmpl"> <div class="tabs"> {{each $item.html("h3", true)}} <div class="tabState_${$index === selectedTabIndex}"> ${$value} </div> {{/each}} </div> <div class="tabBody"> {{html $item.html("div")[selectedTabIndex]}} </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Global for tracking selected tab var selectedTabIndex = 0; // Render the tab strip $("#tabsContent").tmpl().appendTo("#tabsView"); // When a tab is clicked, update the tab strip $("#tabsView") .delegate(".tabState_false", "click", function () { var templateItem = $.tmplItem(this); selectedTabIndex = $(this).index(); templateItem.update(); }); </script> </body> </html>   The “source” for the tab strip is contained in the following template: <script id="tabsContent" type="text/x-jquery-tmpl"> {{wrap "#tabsWrap"}} <h3>Tab 1</h3> <div> Content of tab 1. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 2</h3> <div> Content of tab 2. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 3</h3> <div> Content of tab 3. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> {{/wrap}} </script>   The tab strip is created with a list of H3 elements (which represent each tab) and DIV elements (which represent the body of each tab). Notice that the HTML content is wrapped in the {{wrap}} template tag. This template tag points at the following tabsWrap template: <script id="tabsWrap" type="text/x-jquery-tmpl"> <div class="tabs"> {{each $item.html("h3", true)}} <div class="tabState_${$index === selectedTabIndex}"> ${$value} </div> {{/each}} </div> <div class="tabBody"> {{html $item.html("div")[selectedTabIndex]}} </div> </script> The tabs DIV contains all of the tabs. The {{each}} template tag is used to loop through each of the H3 elements from the source template and render a DIV tag that represents a particular tab. The template item html() method is used to filter content from the “source” HTML template. The html() method accepts a jQuery selector for its first parameter. The tabs are retrieved from the source template by using an h3 filter. The second parameter passed to the html() method – the textOnly parameter -- causes the filter to return the inner text of each h3 element. You can learn more about the html() method at the jQuery website (see the section on $item.html()). The tabBody DIV renders the body of the selected tab. Notice that the {{html}} template tag is used to display the tab body so that HTML content in the body won’t be HTML encoded. The html() method is used, once again, to grab all of the DIV elements from the source HTML template. The selectedTabIndex global variable is used to display the contents of the selected tab. Remote Templates A common feature request for jQuery templates is support for remote templates. Developers want to be able to separate templates into different files. Adding support for remote templates requires only a few lines of extra code (Dave Ward has a nice blog entry on this). For example, the following page uses a remote template from a file named BookTemplate.htm: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Remote Templates</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg" }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg" }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg" }, ]; // Get the remote template $.get("BookTemplate.htm", null, function (bookTemplate) { // Render the books using the remote template $.tmpl(bookTemplate, books).appendTo("#bookContainer"); }); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   The remote template is retrieved (and rendered) with the following code: // Get the remote template $.get("BookTemplate.htm", null, function (bookTemplate) { // Render the books using the remote template $.tmpl(bookTemplate, books).appendTo("#bookContainer"); });   This code uses the standard jQuery $.get() method to get the BookTemplate.htm file from the server with an Ajax request. After the BookTemplate.htm file is successfully retrieved, the $.tmpl() method is used to render an array of books with the template. Here’s what the BookTemplate.htm file looks like: <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> Notice that the template in the BooksTemplate.htm file is not wrapped by a SCRIPT element. There is no need to wrap the template in this case because there is no possibility that the template will get interpreted before you want it to be interpreted. If you plan to use the bookTemplate multiple times – for example, you are paging or sorting the books -- then you should compile the template into a function and cache the compiled template function. For example, the following page can be used to page through a list of 100 products (using iPhone style More paging). <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Template Caching</title> <link href="6_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <h1>Products</h1> <div id="productContainer"></div> <button id="more">More</button> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Globals var pageIndex = 0; // Create an array of products var products = []; for (var i = 0; i < 100; i++) { products.push({ name: "Product " + (i + 1) }); } // Get the remote template $.get("ProductTemplate.htm", null, function (productTemplate) { // Compile and cache the template $.template("productTemplate", productTemplate); // Render the products renderProducts(0); }); $("#more").click(function () { pageIndex++; renderProducts(); }); function renderProducts() { // Get page of products var pageOfProducts = products.slice(pageIndex * 5, pageIndex * 5 + 5); // Used cached productTemplate to render products $.tmpl("productTemplate", pageOfProducts).appendTo("#productContainer"); } function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   The ProductTemplate is retrieved from an external file named ProductTemplate.htm. This template is retrieved only once. Furthermore, it is compiled and cached with the help of the $.template() method: // Get the remote template $.get("ProductTemplate.htm", null, function (productTemplate) { // Compile and cache the template $.template("productTemplate", productTemplate); // Render the products renderProducts(0); });   The $.template() method compiles the HTML representation of the template into a JavaScript function and caches the template function with the name productTemplate. The cached template can be used by calling the $.tmp() method. The productTemplate is used in the renderProducts() method: function renderProducts() { // Get page of products var pageOfProducts = products.slice(pageIndex * 5, pageIndex * 5 + 5); // Used cached productTemplate to render products $.tmpl("productTemplate", pageOfProducts).appendTo("#productContainer"); } In the code above, the first parameter passed to the $.tmpl() method is the name of a cached template. Working with Template Items In this final section, I want to devote some space to discussing Template Items. A new Template Item is created for each rendered instance of a template. For example, if you are displaying a list of 100 products with a template, then 100 Template Items are created. A Template Item has the following properties and methods: data – The data associated with the Template Instance. For example, a product. tmpl – The template associated with the Template Instance. parent – The parent template item if the template is nested. nodes – The HTML content of the template. calls – Used by {{wrap}} template tag. nest – Used by {{tmpl}} template tag. wrap – Used to imperatively enable wrapped templates. html – Used to filter content from a wrapped template. See the above section on wrapped templates. update – Used to re-render a template item. The last method – the update() method -- is especially interesting because it enables you to re-render a template item with new data or even a new template. For example, the following page displays a list of books. When you hover your mouse over any of the books, additional book details are displayed. In the following screenshot, details for ASP.NET Kick Start are displayed. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Template Item</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div class="bookItem"> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> <script id="bookDetailsTemplate" type="text/x-jQuery-tmpl"> <div class="bookItem"> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} <p> ${description} </p> </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg", description: "The most comprehensive book on Microsoft’s new ASP.NET 4.. " }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg", description: "Writing for professional programmers, Walther explains the crucial concepts that make the Model-View-Controller (MVC) development paradigm work…" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg", description: "Visual Studio .NET is the premier development environment for creating .NET applications…." }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg", description: "ASP.NET MVC Unleashed for the iPhone…" }, ]; // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); // Get compiled details template var bookDetailsTemplate = $("#bookDetailsTemplate").template(); // Add hover handler $(".bookItem").mouseenter(function () { // Get template item associated with DIV var templateItem = $(this).tmplItem(); // Change template to compiled template templateItem.tmpl = bookDetailsTemplate; // Re-render template templateItem.update(); }); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   There are two templates used to display a book: bookTemplate and bookDetailsTemplate. When you hover your mouse over a template item, the standard bookTemplate is swapped out for the bookDetailsTemplate. The bookDetailsTemplate displays a book description. The books are rendered with the bookTemplate with the following line of code: // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer");   The following code is used to swap the bookTemplate and the bookDetailsTemplate to show details for a book: // Get compiled details template var bookDetailsTemplate = $("#bookDetailsTemplate").template(); // Add hover handler $(".bookItem").mouseenter(function () { // Get template item associated with DIV var templateItem = $(this).tmplItem(); // Change template to compiled template templateItem.tmpl = bookDetailsTemplate; // Re-render template templateItem.update(); });   When you hover your mouse over a DIV element rendered by the bookTemplate, the mouseenter handler executes. First, this handler retrieves the Template Item associated with the DIV element by calling the tmplItem() method. The tmplItem() method returns a Template Item. Next, a new template is assigned to the Template Item. Notice that a compiled version of the bookDetailsTemplate is assigned to the Template Item’s tmpl property. The template is compiled earlier in the code by calling the template() method. Finally, the Template Item update() method is called to re-render the Template Item with the bookDetailsTemplate instead of the original bookTemplate. Summary This is a long blog entry and I still have not managed to cover all of the features of jQuery Templates J However, I’ve tried to cover the most important features of jQuery Templates such as template composition, template wrapping, and template items. To learn more about jQuery Templates, I recommend that you look at the documentation for jQuery Templates at the official jQuery website. Another great way to learn more about jQuery Templates is to look at the (unminified) source code.

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  • VBA WinHTTPRequest and submitting forms

    - by Hazerider
    Hi. I spent all day yesterday trying to figure out how to submit a form using WinHTTPRequest. I can do it pretty easily with an InternetExplorer object, but the problem is that I need to save a PDF file that gets returned, and I am not sure how to do this with the IE object. Here is the relevant HTML code snippet: <div class="loginHome-left"> <fieldset> <h3>Log in Using</h3> <form> <label for="standardLogin" accesskey="s"> <input name="useLogin" id="standardLogin" value="standard" type="radio" checked="true">Standard Login</label> &nbsp; <label for="rsaSecurID" accesskey="r"> <input name="useLogin" value="rsaSecur" type="radio" id="rsaSecurID" onclick="redirectLogin('ct_logon_securid');return false;">RSA SecurID</label> &nbsp; <label for="employeeNTXP" accesskey="e"> <input name="useLogin" id="employeeNTXP" value="employee" type="radio" onclick="redirectLogin('ct_logon_external_nt');return false; "> Employee Windows Login<br></label> </form> <br> <div class="error">Error: ...</div><br> <form onSubmit="if(validate(this)) {formSubmit();} return false;" name="passwdForm" method="post" action="/UAB/ct_logon"> <input value="custom" name="pageId" type="hidden"> <input value="custom" name="auth_mode" type="hidden"> <input value="/UAB/ct_logon" name="ct_orig_uri" type="hidden"> <INPUT VALUE="" NAME="orig_url" TYPE="hidden"> <input value="" name="lpSp" type="hidden"> <label for="user"> <strong>Username</strong> </label> <input autocomplete="off" name="user" type="text" value="" class="txtFld" onkeypress="return handleEnter(this, event);"> <br> <label for="EnterPassword"> <strong>Password</strong>&nbsp;&nbsp;(<a tabindex="-1" href="/UAB/BCResetWithSecrets">Forgot Your Password?</a>) </label> <input autocomplete="off" name="password" type="password" class="txtFld" onkeypress="return handleEnter(this, event);"> <INPUT id="rememberLogin" name="lpCookie" type="checkbox"> <label for="rememberLogin">Remember My Login Information</label><br> </form> <div class="right"> <br> <input type="image" src="/BC_S/images/bclogin/btn_login.gif" name="" value="Submit" onClick="if(validate(document.forms['passwdForm'])){formSubmit();}return false;"> </div> <div class="clearfix"></div> </fieldset> </div> In order to log in through InternetExplorer, I do the following: Sub TestLogin() Dim ie As InternetExplorer, doc As HTMLDocument, form As HTMLFormElement, inp As Variant Set ie = New InternetExplorer ie.Visible = True ie.navigate "https://URL of the login page" Do Until ie.readyState = READYSTATE_COMPLETE Loop Set doc = ie.document For Each form In doc.forms If InStr(form.innerText, "Password") <> 0 Then form.elements("user").Value = "my_name" form.elements("password").Value = "my_password" Exit For Else End If Next 'This is the unnamed input with an image that is used to submit the form' doc.all(78).Click ie.navigate "https://url of the PDF" Do Until ie.readyState = READYSTATE_COMPLETE Loop Dim filename As String, filenum As Integer filename = "somefile.pdf" filenum = FreeFile Open filename For Binary Access Write As #filenum Write #filenum, doc.DocumentElement.innerText Close #filenum ie.Quit Debug.Print Set ie = Nothing End Sub What I really would like to do is something along the lines of the following: Sub TestLogin3() Dim whr As New WinHttpRequest, postData As String whr.Open "POST", "https://live.barcap.com/UAB/ct_logon", False whr.setRequestHeader "User-Agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" whr.setRequestHeader "Connection", "Keep-Alive" whr.Send whr.WaitForResponse postData = "user=paschom1&password=change01" 'Or the following?' postData = "user=paschom1&password=change01&orig_url=&pageId=custom&auth_mode=custom&ct_orig_uri=/BC/dispatcher&lpSp=&lpCookie=off" whr.Send postData whr.WaitForResponse Debug.Print whr.responseText End Sub It just refuses to work though. Not sure if I need to use more setRequestHeader with Content-Form or something similar, and if I do, not sure what exactly I am supposed to pass it. If anyone has any advice regarding this, it would be hugely appreciated. I could probably use a perl module to do it, but I would rather keep it all in VBA if possible. Thanks, Marc.

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  • Using Lambdas for return values in Rhino.Mocks

    - by PSteele
    In a recent StackOverflow question, someone showed some sample code they’d like to be able to use.  The particular syntax they used isn’t supported by Rhino.Mocks, but it was an interesting idea that I thought could be easily implemented with an extension method. Background When stubbing a method return value, Rhino.Mocks supports the following syntax: dependency.Stub(s => s.GetSomething()).Return(new Order()); The method signature is generic and therefore you get compile-time type checking that the object you’re returning matches the return value defined by the “GetSomething” method. You could also have Rhino.Mocks execute arbitrary code using the “Do” method: dependency.Stub(s => s.GetSomething()).Do((Func<Order>) (() => new Order())); This requires the cast though.  It works, but isn’t as clean as the original poster wanted.  They showed a simple example of something they’d like to see: dependency.Stub(s => s.GetSomething()).Return(() => new Order()); Very clean, simple and no casting required.  While Rhino.Mocks doesn’t support this syntax, it’s easy to add it via an extension method. The Rhino.Mocks “Stub” method returns an IMethodOptions<T>.  We just need to accept a Func<T> and use that as the return value.  At first, this would seem straightforward: public static IMethodOptions<T> Return<T>(this IMethodOptions<T> opts, Func<T> factory) { opts.Return(factory()); return opts; } And this would work and would provide the syntax the user was looking for.  But the problem with this is that you loose the late-bound semantics of a lambda.  The Func<T> is executed immediately and stored as the return value.  At the point you’re setting up your mocks and stubs (the “Arrange” part of “Arrange, Act, Assert”), you may not want the lambda executing – you probably want it delayed until the method is actually executed and Rhino.Mocks plugs in your return value. So let’s make a few small tweaks: public static IMethodOptions<T> Return<T>(this IMethodOptions<T> opts, Func<T> factory) { opts.Return(default(T)); // required for Rhino.Mocks on non-void methods opts.WhenCalled(mi => mi.ReturnValue = factory()); return opts; } As you can see, we still need to set up some kind of return value or Rhino.Mocks will complain as soon as it intercepts a call to our stubbed method.  We use the “WhenCalled” method to set the return value equal to the execution of our lambda.  This gives us the delayed execution we’re looking for and a nice syntax for lambda-based return values in Rhino.Mocks. Technorati Tags: .NET,Rhino.Mocks,Mocking,Extension Methods

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  • Need help modifying my Custom Replace code based on string passed to it

    - by fraXis
    Hello, I have a C# program that will open a text file, parse it for certain criteria using a RegEx statement, and then write a new text file with the changed criteria. For example: I have a text file with a bunch of machine codes in it such as: X0.109Y0Z1.G0H2E1 My C# program will take this and turn it into: X0.109Y0G54G0T3 G43Z1.H2M08 (Note: the T3 value is really the H value (H2 in this case) + 1). T = H + 1 It works great, because the line usually always starts with X so the RegEx statement always matches. My RegEx that works with my first example is as follows: //Regex pattern for: //- X(value)Y(value)Z(value)G(value)H(value)E(value) //- X(value)Y(value)Z(value)G(value)H(value)E(value)M(value) //- X(value)Y(value)Z(value)G(value)H(value)E(value)A(value) //- X(value)Y(value)Z(value)G(value)H(value)E(value)M(value)A(value) //value can be positive or negative, integer or floating point number with multiple decimal places or without any private Regex regReal = new Regex("^(X([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(Y([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(Z([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(G([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(H([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(E([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(M([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*)?(A([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*)?$"); This RegEx works great because sometimes the line of code could also have an M or A at the end such as: X0.109Y0Z1.G0H2E1A2 My problem is now I have run into some lines of code that have this: G90G0X1.5Y-0.036E1Z3.H1 and I need to turn it into this: G90G0X1.5Y-0.036G54T2 G43Z3.H1M08 Can someone please modify my RegEx and code to turn this: G90G0X1.5Y-0.036E1Z3.H1 into: G90G0X1.5Y-0.036G54T2 G43Z3.H1M08 But sometimes the values could be a little different such as: G(value)G(value)X(value)Y(value)E(value)Z(value)H(value) G(value)G(value)X(value)Y(value)E(value)Z(value)H(value)A(value) G(value)G(value)X(value)Y(value)E(value)Z(value)H(value)A(value)(M)value G(value)G(value)X(value)Y(value)E(value)Z(value)H(value)M(value)(A)value But also (this is where Z is moved to a different spot) G(value)G(value)X(value)Y(value)Z(value)E(value)H(value) G(value)G(value)X(value)Y(value)Z(value)E(value)H(value)A(value) G(value)G(value)X(value)Y(value)Z(value)E(value)H(value)A(value)(M)value G(value)G(value)X(value)Y(value)Z(value)E(value)H(value)M(value)(A)value Here is my code that needs to be changed (I did not include the open and saving of the text file since that is pretty standard stuff). //Regex pattern for: //- X(value)Y(value)Z(value)G(value)H(value)E(value) //- X(value)Y(value)Z(value)G(value)H(value)E(value)M(value) //- X(value)Y(value)Z(value)G(value)H(value)E(value)A(value) //- X(value)Y(value)Z(value)G(value)H(value)E(value)M(value)A(value) //value can be pozitive or negative, integer or floating point number with multiple decimal places or without any private Regex regReal = new Regex("^(X([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(Y([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(Z([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(G([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(H([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(E([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*){1}(M([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*)?(A([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]*)?$"); private string CheckAndModifyLine(string line) { if (regReal.IsMatch(line)) //Check the first Regex with line string { return CustomReplace(line); } else { return line; } } private string CustomReplace(string input) { string returnValue = String.Empty; int zPos = input.IndexOf("Z"); int gPos = input.IndexOf("G"); int hPos = input.IndexOf("H"); int ePos = input.IndexOf("E"); int aPos = input.IndexOf("A"); int hValue = Int32.Parse(input.Substring(hPos + 1, ePos - hPos - 1)) + 1; //get H number //remove A value returnValue = ((aPos == -1) ? input : input.Substring(0, aPos)); //replace Z value returnValue = Regex.Replace(returnValue, "Z[-]?\\d*\\.*\\d*", "G54"); //replace H value returnValue = Regex.Replace(returnValue, "H\\d*\\.*\\d*", "T" + hValue.ToString() + ((aPos == -1) ? String.Empty : input.Substring(aPos, input.Length - aPos))); //replace E, or E and M value returnValue = Regex.Replace(returnValue, "E\\d*\\.*\\d(M\\d*\\.*\\d)?", Environment.NewLine + "G43" + input.Substring(zPos, gPos - zPos) + input.Substring(hPos, ePos - hPos) + "M08"); return returnValue; } I tried to modify the above code to match the new line of text I am encountering (and split into two lines like my first example) but I am failing miserably. Thanks so much.

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  • Page output caching for dynamic web applications

    - by Mike Ellis
    I am currently working on a web application where the user steps (forward or back) through a series of pages with "Next" and "Previous" buttons, entering data until they reach a page with the "Finish" button. Until finished, all data is stored in Session state, then sent to the mainframe database via web services at the end of the process. Some of the pages display data from previous pages in order to collect additional information. These pages can never be cached because they are different for every user. For pages that don't display this dynamic data, they can be cached, but only the first time they load. After that, the data that was previously entered needs to be displayed. This requires Page_Load to fire, which means the page can't be cached at that point. A couple of weeks ago, I knew almost nothing about implementing page caching. Now I still don't know much, but I know a little bit, and here is the solution that I developed with the help of others on my team and a lot of reading and trial-and-error. We have a base page class defined from which all pages inherit. In this class I have defined a method that sets the caching settings programmatically. For pages that can be cached, they call this base page method in their Page_Load event within a if(!IsPostBack) block, which ensures that only the page itself gets cached, not the data on the page. if(!IsPostBack) {     ...     SetCacheSettings();     ... } protected void SetCacheSettings() {     Response.Cache.AddValidationCallback(new HttpCacheValidateHandler(Validate), null);     Response.Cache.SetExpires(DateTime.Now.AddHours(1));     Response.Cache.SetSlidingExpiration(true);     Response.Cache.SetValidUntilExpires(true);     Response.Cache.SetCacheability(HttpCacheability.ServerAndNoCache); } The AddValidationCallback sets up an HttpCacheValidateHandler method called Validate which runs logic when a cached page is requested. The Validate method signature is standard for this method type. public static void Validate(HttpContext context, Object data, ref HttpValidationStatus status) {     string visited = context.Request.QueryString["v"];     if (visited != null && "1".Equals(visited))     {         status = HttpValidationStatus.IgnoreThisRequest; //force a page load     }     else     {         status = HttpValidationStatus.Valid; //load from cache     } } I am using the HttpValidationStatus values IgnoreThisRequest or Valid which forces the Page_Load event method to run or allows the page to load from cache, respectively. Which one is set depends on the value in the querystring. The value in the querystring is set up on each page in the "Next" and "Previous" button click event methods based on whether the page that the button click is taking the user to has any data on it or not. bool hasData = HasPageBeenVisited(url); if (hasData) {     url += VISITED; } Response.Redirect(url); The HasPageBeenVisited method determines whether the destination page has any data on it by checking one of its required data fields. (I won't include it here because it is very system-dependent.) VISITED is a string constant containing "?v=1" and gets appended to the url if the destination page has been visited. The reason this logic is within the "Next" and "Previous" button click event methods is because 1) the Validate method is static which doesn't allow it to access non-static data such as the data fields for a particular page, and 2) at the time at which the Validate method runs, either the data has not yet been deserialized from Session state or is not available (different AppDomain?) because anytime I accessed the Session state information from the Validate method, it was always empty.

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  • JQuery text display problem?

    - by SLAPme
    Kind of new to JQuery and I was wondering how can I state that the users submitted info was saved when they click the submit button by displaying the message Changes saved at the top of the form and then have it disappear when the user leaves the web page and return back to it? Right now my code only displays that changes were saved at the bottom of the form outside of the lists and will not disappear when the users leave the web page and return back to it. Here is the JQuery code. $(function() { $(".save-button").click(function() { $.post($("#contact-form").attr("action"), $("#contact-form").serialize(), function(html) { $("div.contact-info-form").html(html); $('#contact-form').append('<li>Changes saved!</li>'); }); return false; // prevent normal submit }); }); Here is the html code. <div id="contact-info-form" class="form-content"> <h2>Contact Information</h2> <form method="post" action="index.php" id="contact-form"> <fieldset> <ul> <li><label for="address">Address 1: </label><input type="text" name="address" id="address" size="25" class="input-size" value="<?php if (isset($_POST['address'])) { echo $_POST['address']; } else if(!empty($address)) { echo $address; } ?>" /></li> <li><label for="address_two">Address 2: </label><input type="text" name="address_two" id="address_two" size="25" class="input-size" value="<?php if (isset($_POST['address_two'])) { echo $_POST['address_two']; } else if(!empty($address_two)) { echo $address_two; } ?>" /></li> <li><label for="city_town">City/Town: </label><input type="text" name="city_town" id="city_town" size="25" class="input-size" value="<?php if (isset($_POST['city_town'])) { echo $_POST['city_town']; } else if(!empty($city_town)) { echo $city_town; } ?>" /></li> <li><label for="state_province">State/Province: </label> <?php echo '<select name="state_province" id="state_province">' . "\n"; foreach($state_options as $option) { if ($option == $state_province) { echo '<option value="' . $option . '" selected="selected">' . $option . '</option>' . "\n"; } else { echo '<option value="'. $option . '">' . $option . '</option>'."\n"; } } echo '</select>'; ?> </li> <li><label for="zipcode">Zip/Post Code: </label><input type="text" name="zipcode" id="zipcode" size="5" class="input-size" value="<?php if (isset($_POST['zipcode'])) { echo $_POST['zipcode']; } else if(!empty($zipcode)) { echo $zipcode; } ?>" /></li> <li><label for="country">Country: </label> <?php echo '<select name="country" id="country">' . "\n"; foreach($countries as $option) { if ($option == $country) { echo '<option value="' . $option . '" selected="selected">' . $option . '</option>' . "\n"; } else if($option == "-------------") { echo '<option value="' . $option . '" disabled="disabled">' . $option . '</option>'; } else { echo '<option value="'. $option . '">' . $option . '</option>'."\n"; } } echo '</select>'; ?> </li> <li><label for="email">Email Address: </label><input type="text" name="email" id="email" size="25" class="input-size" value="<?php if (isset($_POST['email'])) { echo $_POST['email']; } else if(!empty($email)) { echo $email; } ?>" /><br /><span>We don't spam or share your email with third parties. We respect your privacy.</span></li> <li><input type="submit" name="submit" value="Save Changes" class="save-button" /> <input type="hidden" name="contact_info_submitted" value="true" /> <input type="submit" name="submit" value="Preview Changes" class="preview-changes-button" /></li> </ul> </fieldset> </form> </div>

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  • Subterranean IL: Custom modifiers

    - by Simon Cooper
    In IL, volatile is an instruction prefix used to set a memory barrier at that instruction. However, in C#, volatile is applied to a field to indicate that all accesses on that field should be prefixed with volatile. As I mentioned in my previous post, this means that the field definition needs to store this information somehow, as such a field could be accessed from another assembly. However, IL does not have a concept of a 'volatile field'. How is this information stored? Attributes The standard way of solving this is to apply a VolatileAttribute or similar to the field; this extra metadata notifies the C# compiler that all loads and stores to that field should use the volatile prefix. However, there is a problem with this approach, namely, the .NET C++ compiler. C++ allows methods to be overloaded using properties, like volatile or const, on the parameters; this is perfectly legal C++: public ref class VolatileMethods { void Method(int *i) {} void Method(volatile int *i) {} } If volatile was specified using a custom attribute, then the VolatileMethods class wouldn't be compilable to IL, as there is nothing to differentiate the two methods from each other. This is where custom modifiers come in. Custom modifiers Custom modifiers are similar to custom attributes, but instead of being applied to an IL element separately to its declaration, they are embedded within the field or parameter's type signature itself. The VolatileMethods class would be compiled to the following IL: .class public VolatileMethods { .method public instance void Method(int32* i) {} .method public instance void Method( int32 modreq( [mscorlib]System.Runtime.CompilerServices.IsVolatile)* i) {} } The modreq([mscorlib]System.Runtime.CompilerServices.IsVolatile) is the custom modifier. This adds a TypeDef or TypeRef token to the signature of the field or parameter, and even though they are mostly ignored by the CLR when it's executing the program, this allows methods and fields to be overloaded in ways that wouldn't be allowed using attributes. Because the modifiers are part of the signature, they need to be fully specified when calling such a method in IL: call instance void Method( int32 modreq([mscorlib]System.Runtime.CompilerServices.IsVolatile)*) There are two ways of applying modifiers; modreq specifies required modifiers (like IsVolatile), and modopt specifies optional modifiers that can be ignored by compilers (like IsLong or IsConst). The type specified as the modifier argument are simple placeholders; if you have a look at the definitions of IsVolatile and IsLong they are completely empty. They exist solely to be referenced by a modifier. Custom modifiers are used extensively by the C++ compiler to specify concepts that aren't expressible in IL, but still need to be taken into account when calling method overloads. C++ and C# That's all very well and good, but how does this affect C#? Well, the C++ compiler uses modreq(IsVolatile) to specify volatility on both method parameters and fields, as it would be slightly odd to have the same concept represented using a modifier or attribute depending on what it was applied to. Once you've compiled your C++ project, it can then be referenced and used from C#, so the C# compiler has to recognise the modreq(IsVolatile) custom modifier applied to fields, and vice versa. So, even though you can't overload fields or parameters with volatile using C#, volatile needs to be expressed using a custom modifier rather than an attribute to guarentee correct interoperability and behaviour with any C++ dlls that happen to come along. Next up: a closer look at attributes, and how certain attributes compile in unexpected ways.

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  • How do I get FEATURE_LEVEL_9_3 to work with shaders in Direct3D11?

    - by Dominic
    Currently I'm going through some tutorials and learning DX11 on a DX10 machine (though I just ordered a new DX11 compatible computer) by means of setting the D3D_FEATURE_LEVEL_ setting to 10_0 and switching the vertex and pixel shader versions in D3DX11CompileFromFile to "vs_4_0" and "ps_4_0" respectively. This works fine as I'm not using any DX11-only features yet. I'd like to make it compatible with DX9.0c, which naively I thought I could do by changing the feature level setting to 9_3 or something and taking the vertex/pixel shader versions down to 3 or 2. However, no matter what I change the vertex/pixel shader versions to, it always fails when I try to call D3DX11CompileFromFile to compile the vertex/pixel shader files when I have D3D_FEATURE_LEVEL_9_3 enabled. Maybe this is due to the the vertex/pixel shader files themselves being incompatible for the lower vertex/pixel shader versions, but I'm not expert enough to say. My shader files are listed below: Vertex shader: cbuffer MatrixBuffer { matrix worldMatrix; matrix viewMatrix; matrix projectionMatrix; }; struct VertexInputType { float4 position : POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; struct PixelInputType { float4 position : SV_POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; PixelInputType LightVertexShader(VertexInputType input) { PixelInputType output; // Change the position vector to be 4 units for proper matrix calculations. input.position.w = 1.0f; // Calculate the position of the vertex against the world, view, and projection matrices. output.position = mul(input.position, worldMatrix); output.position = mul(output.position, viewMatrix); output.position = mul(output.position, projectionMatrix); // Store the texture coordinates for the pixel shader. output.tex = input.tex; // Calculate the normal vector against the world matrix only. output.normal = mul(input.normal, (float3x3)worldMatrix); // Normalize the normal vector. output.normal = normalize(output.normal); return output; } Pixel Shader: Texture2D shaderTexture; SamplerState SampleType; cbuffer LightBuffer { float4 ambientColor; float4 diffuseColor; float3 lightDirection; float padding; }; struct PixelInputType { float4 position : SV_POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; float4 LightPixelShader(PixelInputType input) : SV_TARGET { float4 textureColor; float3 lightDir; float lightIntensity; float4 color; // Sample the pixel color from the texture using the sampler at this texture coordinate location. textureColor = shaderTexture.Sample(SampleType, input.tex); // Set the default output color to the ambient light value for all pixels. color = ambientColor; // Invert the light direction for calculations. lightDir = -lightDirection; // Calculate the amount of light on this pixel. lightIntensity = saturate(dot(input.normal, lightDir)); if(lightIntensity > 0.0f) { // Determine the final diffuse color based on the diffuse color and the amount of light intensity. color += (diffuseColor * lightIntensity); } // Saturate the final light color. color = saturate(color); // Multiply the texture pixel and the final diffuse color to get the final pixel color result. color = color * textureColor; return color; }

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  • JQuery form submit Question?

    - by SLAPme
    I'm kind of new to JQuery and was wondering how can I have the following text appear when the user submits there changes <p>Your changes have been saved.</p>? How do I fix my code so it displays this message? JQuery script. $(function() { $(".save-button").click(function() { $.post($("#contact-form").attr("action"), $("#contact-form").serialize(), function(html) { $("div.contact-info-form").html(html); }); return false; // prevent normal submit }); }); Here is the html. <div id="contact-info-form" class="form-content"> <h2>Contact Information</h2> <form method="post" action="index.php" id="contact-form"> <fieldset> <ul> <li><label for="address">Address 1: </label><input type="text" name="address" id="address" size="25" class="input-size" value="<?php if (isset($_POST['address'])) { echo $_POST['address']; } else if(!empty($address)) { echo $address; } ?>" /></li> <li><label for="address_two">Address 2: </label><input type="text" name="address_two" id="address_two" size="25" class="input-size" value="<?php if (isset($_POST['address_two'])) { echo $_POST['address_two']; } else if(!empty($address_two)) { echo $address_two; } ?>" /></li> <li><label for="city_town">City/Town: </label><input type="text" name="city_town" id="city_town" size="25" class="input-size" value="<?php if (isset($_POST['city_town'])) { echo $_POST['city_town']; } else if(!empty($city_town)) { echo $city_town; } ?>" /></li> <li><label for="state_province">State/Province: </label> <?php echo '<select name="state_province" id="state_province">' . "\n"; foreach($state_options as $option) { if ($option == $state_province) { echo '<option value="' . $option . '" selected="selected">' . $option . '</option>' . "\n"; } else { echo '<option value="'. $option . '">' . $option . '</option>'."\n"; } } echo '</select>'; ?> </li> <li><label for="zipcode">Zip/Post Code: </label><input type="text" name="zipcode" id="zipcode" size="5" class="input-size" value="<?php if (isset($_POST['zipcode'])) { echo $_POST['zipcode']; } else if(!empty($zipcode)) { echo $zipcode; } ?>" /></li> <li><label for="country">Country: </label> <?php echo '<select name="country" id="country">' . "\n"; foreach($countries as $option) { if ($option == $country) { echo '<option value="' . $option . '" selected="selected">' . $option . '</option>' . "\n"; } else if($option == "-------------") { echo '<option value="' . $option . '" disabled="disabled">' . $option . '</option>'; } else { echo '<option value="'. $option . '">' . $option . '</option>'."\n"; } } echo '</select>'; ?> </li> <li><label for="email">Email Address: </label><input type="text" name="email" id="email" size="25" class="input-size" value="<?php if (isset($_POST['email'])) { echo $_POST['email']; } else if(!empty($email)) { echo $email; } ?>" /><br /><span>We don't spam or share your email with third parties. We respect your privacy.</span></li> <li><p>Changes have been saved</p><input type="submit" name="submit" value="Save Changes" class="save-button" /> <input type="hidden" name="contact_info_submitted" value="true" /> <input type="submit" name="submit" value="Preview Changes" class="preview-changes-button" /></li> </ul> </fieldset> </form> </div>

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  • i have made a from and want to connect it to a oracle 10g data base using php.can you please assume

    - by nachiket-panse
    http://www.freecsstemplates.org Released for free under a Creative Commons Attribution 2.5 License -- Sitename.com by Free Css Templates MANAGEMEINT INFORMATION SYSTEM   <p class="style2">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;REGISTRY ENTRY FORM </p> <form id="form2" method="post" action=""> <p align="center">&nbsp;</p> <p align="center"><span class="style3">JOB DESCRIPTION :</span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <textarea name="textarea"></textarea> </p> <p align="center"><span class="style3">QUANTITY :</span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name="textfield5" /> </p> <p align="center">&nbsp;<span class="style3">CONTACT PERSON </span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name="textfield3" /> </p> <p align="center">&nbsp;</p> <p align="center"><span class="style3">DIVISION CODE: <textarea name="textarea3"></textarea> </span></p> <p align="center"><span class="style3">ACCEPTANCE DATE </span>: <input type="text" name="textfield4" /> </p> <p align="center"><span class="style3">REFERENCE NUMBER :</span> <input type="text" name="textfield2" /> </p> <p align="center"><span class="style3">CLASSIFICATION :</span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name="textfield" /></p> <p align="center">&nbsp;</p> <p align="center"><span class="style3">CUMULATIVE COST: </span> <select name="select"> </select> </p> <p align="center"><span class="style3">PLANNING ENGR: </span> <textarea name="textarea2"></textarea> </p> <p align="center"><span class="style3">PLANNING: </span> <input type="text" name="textfield6" /> </p> <p align="center"> <span class="style3">FILL THE COMPLETION DATE: </span> <input type="text" name="textfield7" /> </p> <p align="center"><span class="style3">REMARKS: </span> <input type="text" name="textfield8" /> </p> <p align="center">&nbsp;</p> <p align="center"> <input type="submit" name="SAVE" value="SAVE" /> <input type="submit" name="Submit2" value="LIST" /> <input type="submit" name="Submit" value="ADD" /> <input type="submit" name="Submit3" value="CANCEL" /> <input type="submit" name="BACK" value="BACK" /></p> <p align="center">&nbsp;</p> <p align="center">&nbsp;</p> <p align="center">&nbsp;</p> <p align="center">&nbsp;</p> <p align="center">&nbsp;</p> </form> <p align="center" class="style2">&nbsp;</p>

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  • Copying one form's values to another form using JQuery

    - by rsturim
    I have a "shipping" form that I want to offer users the ability to copy their input values over to their "billing" form by simply checking a checkbox. I've coded up a solution that works -- but, I'm sort of new to jQuery and wanted some criticism on how I went about achieving this. Is this well done -- any refactorings you'd recommend? Any advice would be much appreciated! The Script <script type="text/javascript"> $(function() { $("#copy").click(function() { if($(this).is(":checked")){ var $allShippingInputs = $(":input:not(input[type=submit])", "form#shipping"); $allShippingInputs.each(function() { var billingInput = "#" + this.name.replace("ship", "bill"); $(billingInput).val($(this).val()); }) //console.log("checked"); } else { $(':input','#billing') .not(':button, :submit, :reset, :hidden') .val('') .removeAttr('checked') .removeAttr('selected'); //console.log("not checked") } }); }); </script> The Form <div> <form action="" method="get" name="shipping" id="shipping"> <fieldset> <legend>Shipping</legend> <ul> <li> <label for="ship_first_name">First Name:</label> <input type="text" name="ship_first_name" id="ship_first_name" value="John" size="" /> </li> <li> <label for="ship_last_name">Last Name:</label> <input type="text" name="ship_last_name" id="ship_last_name" value="Smith" size="" /> </li> <li> <label for="ship_state">State:</label> <select name="ship_state" id="ship_state"> <option value="RI">Rhode Island</option> <option value="VT" selected="selected">Vermont</option> <option value="CT">Connecticut</option> </select> </li> <li> <label for="ship_zip_code">Zip Code</label> <input type="text" name="ship_zip_code" id="ship_zip_code" value="05401" size="8" /> </li> <li> <input type="submit" name="" /> </li> </ul> </fieldset> </form> </div> <div> <form action="" method="get" name="billing" id="billing"> <fieldset> <legend>Billing</legend> <ul> <li> <input type="checkbox" name="copy" id="copy" /> <label for="copy">Same of my shipping</label> </li> <li> <label for="bill_first_name">First Name:</label> <input type="text" name="bill_first_name" id="bill_first_name" value="" size="" /> </li> <li> <label for="bill_last_name">Last Name:</label> <input type="text" name="bill_last_name" id="bill_last_name" value="" size="" /> </li> <li> <label for="bill_state">State:</label> <select name="bill_state" id="bill_state"> <option>-- Choose State --</option> <option value="RI">Rhode Island</option> <option value="VT">Vermont</option> <option value="CT">Connecticut</option> </select> </li> <li> <label for="bill_zip_code">Zip Code</label> <input type="text" name="bill_zip_code" id="bill_zip_code" value="" size="8" /> </li> <li> <input type="submit" name="" /> </li> </ul> </fieldset> </form> </div>

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  • Oracle Fusion Supply Chain Management (SCM) Designs May Improve End User Productivity

    - by Applications User Experience
    By Applications User Experience on March 10, 2011 Michele Molnar, Senior Usability Engineer, Applications User Experience The Challenge: The SCM User Experience team, in close collaboration with product management and strategy, completely redesigned the user experience for Oracle Fusion applications. One of the goals of this redesign was to increase end user productivity by applying design patterns and guidelines and incorporating findings from extensive usability research. But a question remained: How do we know that the Oracle Fusion designs will actually increase end user productivity? The Test: To answer this question, the SCM Usability Engineers compared Oracle Fusion designs to their corresponding existing Oracle applications using the workflow time analysis method. The workflow time analysis method breaks tasks into a sequence of operators. By applying standard time estimates for all of the operators in the task, an estimate of the overall task time can be calculated. The workflow time analysis method has been recently adopted by the Applications User Experience group for use in predicting end user productivity. Using this method, a design can be tested and refined as needed to improve productivity even before the design is coded. For the study, we selected some of our recent designs for Oracle Fusion Product Information Management (PIM). The designs encompassed tasks performed by Product Managers to create, manage, and define products for their organization. (See Figure 1 for an example.) In applying this method, the SCM Usability Engineers collaborated with Product Management to compare the new Oracle Fusion Applications designs against Oracle’s existing applications. Together, we performed the following activities: Identified the five most frequently performed tasks Created detailed task scenarios that provided the context for each task Conducted task walkthroughs Analyzed and documented the steps and flow required to complete each task Applied standard time estimates to the operators in each task to estimate the overall task completion time Figure 1. The interactions on each Oracle Fusion Product Information Management screen were documented, as indicated by the red highlighting. The task scenario and script provided the context for each task.  The Results: The workflow time analysis method predicted that the Oracle Fusion Applications designs would result in productivity gains in each task, ranging from 8% to 62%, with an overall productivity gain of 43%. All other factors being equal, the new designs should enable these tasks to be completed in about half the time it takes with existing Oracle Applications. Further analysis revealed that these performance gains would be achieved by reducing the number of clicks and screens needed to complete the tasks. Conclusions: Using the workflow time analysis method, we can expect the Oracle Fusion Applications redesign to succeed in improving end user productivity. The workflow time analysis method appears to be an effective and efficient tool for testing, refining, and retesting designs to optimize productivity. The workflow time analysis method does not replace usability testing with end users, but it can be used as an early predictor of design productivity even before designs are coded. We are planning to conduct usability tests later in the development cycle to compare actual end user data with the workflow time analysis results. Such results can potentially be used to validate the productivity improvement predictions. Used together, the workflow time analysis method and usability testing will enable us to continue creating, evaluating, and delivering Oracle Fusion designs that exceed the expectations of our end users, both in the quality of the user experience and in productivity. (For more information about studying productivity, refer to the Measuring User Productivity blog.)

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