Keep event handler or action method as clean as possible. Never hardcode a path or drive name in code. Get the application path programmatically and use relative path. Use input or output classes System.
IO to achieve this. Always do null check for objects and complex objects before accessing them. Error message to end use should be user friendly and self-explanatory but log the actual exception details using logger. Create constants for this and use them in application.
Avoid public methods and properties to expose, unless they really need to be accessed from outside the class. Use internal if they are accessed only within the same assembly and use private if used in same class.
Avoid passing many parameters to function. If you have more than parameters use class or structure to pass it. While working with collection be aware of the below points, While returning collection return empty collection instead of returning null when you have no data to return.
Always check Any operator instead of checking count i. The using statements should be sort by framework namespaces first and then application namespaces in ascending order.
If you are opening database connections, sockets, file stream etc, always close them in the finally block. This will ensure that even if an exception occurs after opening the connection, it will be safely closed in the finally block. Simplify your code by using the C using statement. If you have a try-finally statement in which the only code in the finally block is a call to the Dispose method, use a using statement instead.
Always catch only the specific exception instead of catching generic exception. Use StringBuilder class instead of String when you have to manipulate string objects in a loop.
This is needed in order to use the WebClient class without requiring a fully qualified namespace. The WebClient class itself is really easy to use. The very simplest example of downloading a file is as follows.
The DownloadFile method accepts a URL to download a file from and a local file path to download the file to. All of the above happens synchronously i. Unfortunately, the DownloadFile method does not provide a way of reporting progress, as it is a synchronous method. However, there is a built-in way of asynchronously downloading a file and reporting progress with the WebClient class, as demonstrated in the example below.
The above code is very similar to the synchronous example. The DownloadProgressChanged event is fired periodically as the download progresses and provides access to some useful properties such as BytesReceived and ProgressPercentage. As expected, the DownloadFileCompleted event is fired whenever the file download has completed. As it stands, the above code will continue past the DownloadFileAsync method call while the download is in progress, since it is an asynchronous method call.
In order to download the file asynchronously using the DownloadFileAsync method and wait until the download has completed before continuing program execution, we need to dip into the world of reset events.
The AutoResetEvent in the above code allows us to wait at the point where the WaitOne method is called. Viewed 8k times. Move tempfile, Path. Combine Environment. Combine Path. GetTempPath , Path. CurrentDirectory, Settings. DownloadFolder, Path. DownloadFolder, filename ; WriteData tempfile ; File. CurrentDirectory, filename ; Because some files are in use at the time I don't have the option of writing the file directly to where it ends up going.
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Connect and share knowledge within a single location that is structured and easy to search. Please let me know which is the best practice. Is it possible to cancel the ongoing download using the above mentioned terms, If so please provide me the snippets. The download manager is a system service that handles long-running HTTP downloads.
Clients may request that a URI be downloaded to a particular destination file. The download manager will conduct the download in the background, taking care of HTTP interactions and retrying downloads after failures or across connectivity changes and system reboots. So if you do not want to take headache of HTTP connection error handling, and just want to pass source and destination of a file, then use DownloadManager. And You can cancel downloads via DownloadManager by calling its remove long For this you need the ID of the download.
The keyword new in the method declaration context is supposedly a feature. You need this so your clone matches the derived type. Judging from that code, you might think C includes the return type in the method footprint the class method resolver is using. Method constraints are also ignored for method resolution. The code in Figure 3 shows how the ability to substitute might be broken. Consider your inheritors. One of them could modify the isMoonWalking field at random.
If that were to happen, the base class runs the risk of missing a critical cleanup section. The isMoonWalking field should be private. If inheritors need to know, there should be a protected getter property that provides access, but not modification. Wise and occasionally pedantic programmers will take this a step further.
The pattern of requiring a base call is admissible, but not ideal. Liskov Substitution also requires inheritors to not throw new exception types although inheritors of exceptions already thrown in the base class are fine. C has no way to enforce this. Each interface should have a specific purpose. By extrapolation, the larger the interface, the more likely it includes methods that not all implementers can achieve. Consider an old and common interface pair from the Microsoft.
NET Framework:. Oftentimes, whoever creates these data collections wants to prevent anyone from modifying the data. Many data stores would like to share a common, indexable non-writable interface.
Consider data analysis or data searching software. They typically read in a large log file or database table for analysis. Modifying the data was never part of the agenda. Admittedly, the IEnumerable interface was intended to be the minimal, read-only interface. With the addition of LINQ extension methods, it has started to fulfill that destiny. Microsoft has also recognized the gap in indexable collection interfaces.
The company has addressed this in the 4. In other words, before you can iterate the collection, you must first potentially lock on its SyncRoot.
A number of inheritors even implemented those particular items explicitly just to help hide their shame at having to implement them.
The expectation in multi-threaded scenarios became that you lock on the collection everywhere you use it rather than using the SyncRoot. Most of you want to encapsulate your collections so they can be accessed in a thread-safe fashion. Instead of using foreach, you must encapsulate the multi-threaded data store and only expose a ForEach method that takes a delegate instead. Fortunately, newer collection classes such as the concurrent collections in the.
NET Framework 4 or the immutable collections now available for the. NET Framework 4. NET Stream abstraction shares the same faults of being way too large, including both readable and writable elements and synchronization flags.
Compare if stream. CanWrite to if stream is IWritableStream.
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