LINQ TO OBJECTS in .net C#

Creation barcode data matrix in .net C# LINQ TO OBJECTS

The signature is stored in a binary format, and there is no easy way to convert the binary signature into a readable format, as there is for the keys. Therefore, the RsaSignature.bin file is embedded as a binary resource into a .NET Micro Framework application. Listing 8-4 shows how to verify a signature with the .NET Micro Framework. Listing 8-4. Verifying an RSA Signature byte[] modulus = new byte[] { }; byte[] publicExponent = new byte[128]; publicExponent[0] = 0x01; publicExponent[2] = 0x01; byte[] signature = Resources.GetBytes(Resources.BinaryResources.RsaSignature); string messageText = "Hello World!"; byte[] messageBytes = Encoding.UTF8.GetBytes(messageText); //Verification of a signature Key_RSA rsa = new Key_RSA(modulus, publicExponent); bool valid = rsa.VerifySignature(messageBytes, 0, messageBytes.Length, signature, 0, signature.Length); if (valid) Debug.Print("Signature is valid.") else Debug.Print("Signature is NOT valid.");

Take the following into account before choosing ASP.NET MVC:

Mathematical functions are implemented in the .NET Micro Framework in the same way as in the full .NET Framework in the System.Math class. This class was substantially trimmed, however, for the .NET Micro Framework (see Listing 4-18). For example, for the methods Abs, Min, and Max, only the integer overloads are available. Floating point numbers such as float and double lack support, and trigonometric functions like the computation of sine and cosine were completely eliminated from the class. Listing 4-18. The System.Math Class namespace System { public static class Math { public const double E = 2.71828; public const double PI = 3.14159; public public public public public public public } } In addition to System.Math, there is a .NET Micro Framework specific Math class, located in the Microsoft.SPOT namespace (see Listing 4-19). The Microsoft.SPOT.Math class exposes methods for the calculation of sine and cosine as well as for generating random numbers. Listing 4-19. The Microsoft.SPOT.Math Class namespace Microsoft.SPOT { public static class Math { public static int Sin(int angle); public static int Cos(int angle); public static void Randomize(); public static int Random(int modulo); } } static static static static static static static int Abs(int val); int Min(int val1, int val2); int Max(int val1, int val2); double Round(double a); double Ceiling(double a); double Floor(double d); double Pow(double x, double y);

AddFirst(T)

Sometimes the Data Access layer can be as simple as a series of methods that use ADO.NET directly to retrieve or store data. In other circumstances, the Data Access layer is more complex, providing a more abstract or even metadata-driven way to get at data. In these cases, the Data Access layer can contain a lot of complex code to provide this more abstract data access scheme. The framework created in this book doesn t restrict how you implement your Data Access layer. The examples in the book use LINQ to SQL, but you could also use ADO.NET or use some other metadata-driven Data Access layer directly if you prefer. Another common role for the Data Access layer is to provide mapping between the object-oriented business logic and the relational data in a data store. A good object-oriented model is almost never the same as a good relational database model. Objects often contain data from multiple tables, or even from multiple databases; or conversely, multiple objects in the model can represent a single table. The process of taking the data from the tables in a relational model and getting it into the object-oriented model is called object-relational mapping (ORM), and I ll have more to say on the subject in 2.

Note The reason that we won t be using XAML is that the SharePoint Designer takes care of this for us.

When selling movie tickets, ticket sales constitute an important statistic, as they indicate the popularity and success of a movie. In a traditional programming approach, ticket sales are calculated by iterating a collection of Tickets. The total would be generated each time a ticket sales total is requested. Another approach would be to use a closure functor, as shown in the following source code for calculating the total sales of a movie: public class TicketsBuilder { private class StatisticsCounter { private double _runningTotal; public StatisticsCounter() { _runningTotal = 0.0; } public void ClosureMethod( Ticket ticket) { _runningTotal += ticket.Price; } } public static IList<Ticket> CreateCollection() { return new Devspace.Commons.Collections.ClosureAddProxy< Ticket>( new List< Ticket>(), new Devspace.Commons.Functors.DelegateClosure< Ticket>( new StatisticsCounter().ClosureMethod)); } } TicketsBuilder is a class that has a method, CreateCollection, that creates an IList<> instance. The method CreateCollection instantiates the type ClosureAddProxy<>, which implements the Proxy pattern for the closure functor. The parent collection for ClosureAddProxy<> is List<>. The delegate used for the closure functor is StatisticsCounter.ClosureMethod. Like in the comparer functor example, every time an element is added to the returned IList<> instance, DelegateAddClosure<> will call the closure delegate. Each time the closure delegate method StatisticsCounter.ClosureMethod is called, the input price is added to the total ticket sales. The class StatisticsCounter.ClosureMethod has a problem in that it isn t entirely accurate. Imagine the scenario where a person buys a ticket and then asks for his or her money back or decides to watch a different movie. The ticket would need to be removed from the collection, and the total sales variable, _runningTotal, would need to be decremented by the price of the removed ticket. Even if it s impossible to get money back, it isn t possible to use such logic for all applications. The problem of the corrupted data needs to be solved. The reason why ticket sales can only be incremented is because ClosureAddProxy overrides the methods that add elements to the collection. The solution is to use a closure delegate that overrides the remove element methods. As I mentioned earlier, even though it s tempting to merge add and remove closure proxies, I don t