} #endregion in C#.net

Implement Data Matrix barcode in C#.net } #endregion

To better understand the concept of custom dependencies, think of the following example. You need to cache the return value of a Web service method say, the currently reported temperature in a particular city. You can define a custom dependency class that caches the current value upon instantiation and polls the Web service to detect changes. When a change is detected, the cached key is invalidated. A good way to poll a local or remote resource is through a timer callback. Let s break the procedure into a few steps: 1. The custom WeatherCacheDependency class gets ready for the overall functionality. It initializes some internal properties and caches at least the polling rate and the current temperature. After initialization, the dependency object sets up a timer callback to poll the Web service for up-to-date information. Polling the Web service means calling a particular Web method at regular intervals. In the callback, the result of the Web method the current temperature in the city is compared to the previously stored temperature. If the two temperatures differ, the linked cache key is promptly emptied.

BeginInvoke takes the same parameters as the original method, plus two. The extra two parameters are the delegate to call back when the asynchronous operation is complete and state information is passed to the delegate. BeginInvoke returns an IAsyncResult needed to obtain the return values from the method call later. BeginInvoke starts the asynchronous operation and returns. At some point in the code, however, you must synchronize your primary thread and the secondary thread on which the asynchronous request is working. You can do this in a few ways. For example, you can block the primary thread waiting for the other to terminate:

For this task, complete at least Practices 1 and 2. If you want experience publishing to a public hosting provider, complete Practice 3 as well.

The Good, the Bad, and the . . . Unknown!

By default, when you set up a wireless connection on your computer, it s available to all users of your computer. You can optionally make a connection available only to the user who s currently logged on. To make that option available, you must make a setting before you set up the wireless network connection, as follows: 1. In Network And Sharing Center, click Manage Wireless Networks. 2. In the Command bar of the Manage Wireless Networks window, click Profile Types.

Interface Declaration Context Member of Namespace Accessibility public protected private internal protected internal Inheritance new abstract

public static void Main() { SomeValueType v = new SomeValueType(0); Object o = new Object(); Int32 n = v.CompareTo(v); // Undesired boxing n = v.CompareTo(o); // InvalidCastException }

C# public interface IRegionNavigationService : INavigateAsync { IRegion Region {get; set;} IRegionNavigationJournal Journal {get;} event EventHandler<RegionNavigationEventArgs> Navigating; event EventHandler<RegionNavigationEventArgs> Navigated; event EventHandler<RegionNavigationFailedEventArgs> NavigationFailed; }

namespace SimpleSPActionQueries {

Use all the data available to make your hypothesis When creating a hypothesis about the source of a defect, account for as much of the data as you can in your hypothesis. In the example, you might have noticed that Fruit-Loop, Frita was out of order and created a hypothesis that names beginning with an F are sorted incorrectly. That s a poor hypothesis because it doesn t account for the fact that Modula, Mildred was out of order or that names are sorted correctly the second time around. If the data doesn t fit the hypothesis, don t discard the data ask why it doesn t fit, and create a new hypothesis.

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Page 59 channels on your computer is to connect the cable or satellite TV feed to a VCR and use the tuner on your VCR to change channels. Connecting a satellite or cable TV feed to your computer so you can record video from it is discussed later in this chapter. Another method is to have a TV tuner card attached to your computer. With a TV tuner card, you can change channels on your computer without using an external piece of hardware, such as a VCR. Connecting a TV tuner card to your computer and your satellite or cable TV feed is also shown later in this chapter. Broadcasting Standards Around the world, there are different standards used for TV broadcasts. These standards also affect the recording and playback of different video sources, such as video cameras and VCRs. These different standards can directly affect your work, especially if you have coworkers in other parts of the world who may need to play back your recorded tapes. The following section gives you a brief overview of the different broadcasting standards and the countries or regions in which they are used. This distinction is important because if you are in a country or region that uses one standard and you try to send tapes to coworkers in a country or region that uses another standard, there is a good chance that they will not be able to play back your tape on their video cameras or VCRs. Today, there are a few video sources that play back all the dominant standards. However, these video devices are usually quite expensive. In Microsoft Producer, you can record from a device that uses any of the three different broadcasting and recording standards described in this section. Because the video is converted when it is recorded to your computer, anyone around the world who has a computer and has access to your presentation can watch it. Not only can you share your presentations with audiences around the world, but you also eliminate the playback problems that arise when sharing video with people in countries or regions that use a different broadcasting standard. National Television System Committee (NTSC) The National Television System Committee (NTSC) standard is the broadcasting standard that is used in the United States, Mexico, Japan, and Canada. Because NTSC is the standard for broadcasting in these countries, most video cameras and VCRs record and play back video using the NTSC standard. The NTSC standard has a resolution of 525 lines per frame. The NTSC standard plays back at 30 frames per second. Phase Alternate Lines (PAL) The Phase Alternate Lines (PAL) standard is the broadcasting standard that is used in much of Western Europe, including the United Kingdom. A few other countries and regions, including China and Australia, also use the PAL standard. A vast majority of video