Tales From Developer Desk

Parallel Programming in .NET 4.0

Samir — Sun, 13 Dec 2009 13:45:41 +0000

There is a nice article on Parallel Programming through samples in .NET 4.0 at

http://blogs.msdn.com/pfxteam/archive/2009/12/09/9934811.aspx?utm_medium=Twitter&utm_source=Shared

Happy Asynchronous Programming!!!

Nice Article About Garbage Collection

Samir — Wed, 02 Dec 2009 16:54:47 +0000

I am trying to exploring the .NET Memory Management, I have came across the nice article about .NET Garbage Collection http://msdn.microsoft.com/en-us/magazine/bb985010.aspx .
Something worth to read it!!

How to publish Metadata through Endpoints

Samir — Sun, 15 Nov 2009 02:07:34 +0000

WCF allows us to publish the metadata using HTTP Get Protocol. Client can access the metadata using HTTP Get Request followed with ?wsdl query string. I assume here you should know about Service Behaviors and Endpoint concept in WCF. If you don’t please read the article at http://msdn.microsoft.com/en-us/library/aa480210.aspx

Two steps are required to configure the service so it can publish the metadata. You can do it either programmatically or through a configuration file. I would recommend doing it through configuration file unless there is a need. Because Administrator can change the configuration without recompiling the application.

Add the ServiceMetaDataBehavior in Service Behaviors Collection. Reference this behavior while specifying the service.
Create Metadata exchange endpoint. This special endpoint can append the mex to the HTTP address that the service uses. This endpoint has following ABC (Address, Binding and Contract)

Address – service address followed by “mex”
Binding – it uses mexHttpBinding as the binding. You can also use mexTCPBinding and mexNamedPipeBinding
Contract – it uses “IMetaDataExchange” as a contract

Following configuration file shows the how PayrollService expose the metadata through HTTP-Get Enabled.

This can also be achieved programmatically as follows.

Commands in WPF

Samir — Sat, 14 Nov 2009 19:59:53 +0000

What is Command?

Command represents the high level task that is performed by application. For e.g. Save is task of persisting the document on File System. Similarly, Open is task of opening the document specified as an argument. Commands in WPF allow you to use a centralized architecture for tasks. Using commands we can associate any number of UI Controls or input gestures to command and bind that command to command handler that is executed when controls are activated or gestures are performed.

One of the advantage of Command is it keeps the track of whether it is available or not. If it is disabled, UI elements associated with that command are also disabled.

Command Architecture

It consists of following four parts.

Command which represents the high level task
Command Source is UI control or gesture which invokes the command
Command Handler is the method that is executed when the command is invoked
Command Binding which is glue between Command and Command Handler.

How to Implement a Command

Associate the command with any control in the user interface and add any gestures to the command
Create a method to handle it
Create CommandBinding that binds the command object with command handler and optionally to a method that handles Command.CanExecute
Add the commandbinding object to the commandbindings collection object associated with control or window where the command is invoked.

How to invoke a Command

There are three ways to invoke the command.

By associating the command with controls :- WPF controls such as Button, Menu Item implements ICommandSource interface which allows them to have command associated with them that is fired automatically when the control is invoked or pressed. For e.g., Button and MenuItem controls implement ICommandSource and thus expose a Command property. When this property is set to a Command that command is executed automatically when the control is clicked. Following code is sample xaml to associate a command with Button.
Invoking Commands with Mouse and Keyboard Gestures

WPF makes it easy to attach a command with any input gestures. For e.g. if we want to attach Copy command with keyboard input gesture Ctrl+c, we can do it as following code sample.
Invoking Commands from code: – it is also possible to invoke a command directly from code in response to event. To invoke a command, we can simple call the Command.Execute method as shown below where aParameter is required parameter data for the command. TargetConrol is the control where command Originates.

Command Handlers

Command Handlers have the following signature.

ExecutedRoutedEventArgs is derived from RoutedEventArgs and thus exposes all the members that RoutedEventArgs does.

Command Bindings

Command binding provides the glue between the Command and Command Handler. Following code shows how to create and register a Command Binding.

This post demonstrates powerful feature Command of WPF which is widely used to build WPF application. In the next post, I will go through how to create Custom Commands for the control step by step with an example.

Welcome to Samir’s thoughts

Samir — Tue, 06 Oct 2009 13:22:03 +0000

Hello Universe,

Welcome to Samir’s Blog!!!!

I decided to spread the Technology to solve the real world problem a long back. Finally the day is here. Today I am announcing the publishing my own blog where I will share the thoughts related to .NET Technologies.

I urge you to help me out to make this more community firendly and enjoyable!!!!!

Enjoy the Blog!!!