.NET/Java PDF, Tiff, Barcode SDK Library

By setting the ServiceContract attribute s CallbackContract property, we ve declared that this is a duplex contract, and have identified the interface that defines the client side of the contract. Example 13-9 also makes a couple of other changes that turn out to be necessary for our service to work as intended: we ve set the SessionMode property of the ServiceContract attribute, and we ve added a couple of extra methods to enable clients to connect and disconnect. We ve also removed the string name argument from PostNote as you ll see, this will turn out to be redundant. All of these changes are related to sessions.

2d barcode excel 2013, free barcode font excel mac, free barcode macro excel 2007, excel 2010 barcode control, excel barcode add-in from tbarcode office, barcode generator for excel free download, barcode creator excel 2007, barcode generator excel download, barcode check digit excel formula, barcode plugin excel 2007,

Note The sv_SE part of the name is built from combining the language code according to ISO 639-1 and

The ServiceContract attribute s SessionMode property determines the nature of the relationship between the server and any particular client. By default, the relationship is presumed to be transient, not necessarily lasting any longer than a single operation. This reflects the fact that WCF is designed to support web services, and HTTP does not offer any idea of a connection between the client and the server that lasts longer than a single request.

None); Next set the line width to 2 pixels to make the chart stand out a little more clearly, and fill the background for the pane with a graded fill between white and antique white: priceCurveLineWidth = 20F; paneAxisFill = new Fill(ColorWhite, ColorAntiqueWhite); Finally, call the AxisChange event to render the graph: paneAxisChange(g); This will draw the graph to the web form Figure 11-17 shows this in action for the stock ticker SBUX with no date specified, thus showing the entire price history that Yahoo offers, going back to 1992..

It s true that HTTP allows a single TCP connection to be reused across multiple requests, but this is just a performance optimization, and nothing is allowed to depend on it. Either the client or the server is free to close the connection at the end of a request, forcing a new one to be established for the next operation, without changing the semantics of the operations. (And even if the client and server both want to keep the connection alive between requests, a proxy in the middle is free to overrule them.) Logically speaking, each HTTP request is completely disassociated from the ones that came before or after.

This connectionless behavior is very useful for scalability and robustness it means you can load-balance across large numbers of web servers, and it doesn t greatly matter whether all of a particular client s requests are handled by the same machine. It s often possible to take a single machine in a web farm out of service without disrupting any of the clients. However, the absence of connections is sometimes unhelpful some applications need some sort of session concept. For example, it would be annoying to have to type in your username and password every time you move from one page to another in a website once you ve logged in to a website, you want it to remember

the country code according to ISO 3166-1. The application name is just an informal name for the application. This naming convention is only by convention you can name your translations any way you like.

who you are Likewise, if our chat application is going to be able to call clients back to notify them that notes have arrived, that implies that the application needs to know which clients are currently connected Although HTTP has no standard way to represent a session, various ad hoc systems have been developed to add such a feature Websites typically use cookies (Cookies are not part of the HTTP specification, but they are supported by all popular web browsers Some users disable them, though, so they re not necessarily universally available) The web service standards supported by WCF prefer a slightly different solution it s similar to how cookies work, but it puts the relevant information in the messages being sent, rather than in the HTTP headers Since our contract is now duplex, it requires the ability to maintain a connection between each client and the server.