There are occasions however when we want to take care of these details ourselves, and in this tutorial we learn how to access the database connection- and command-level settings in the TableAdapter.
A more powerful signaling construct is provided by the Monitor class, via the static methods Wait and Pulse and PulseAll. The principle is that you write the signaling logic yourself using custom flags and fields enclosed in lock statementsand then introduce Wait and Pulse commands to prevent spinning.
Furthermore, Wait and Pulse can be amenable in situations where all of the wait handles are parsimoniously challenged. Wait and Pulse signaling, however, has some disadvantages over event wait handles: You must remember to protect all variables related to the signaling logic with locks. Wait and Pulse also have a peculiar aversion to dabblers: Fortunately, there is a simple pattern of use that tames Wait and Pulse.
In terms of performance, calling Pulse takes around a hundred nanoseconds on a era desktop — about a third of the time it takes to call Set on a wait handle. The overhead for waiting on uncontended signal is entirely up to you — because you implement the logic yourself using ordinary fields and variables.
In practice, this is very simple and amounts purely to the cost of taking a lock. Define a single field for use as the synchronization object, such as: This pattern allows any thread to wait at any time for any condition. Wait method does the following, in order: If the lock is contended, then it blocks until the lock is available.
This means that despite appearances, no lock is held on the synchronization object while Monitor. Wait awaits a pulse: Wait is designed for use within a lock statement; it throws an exception if called otherwise. The same goes for Monitor. As soon as we release the lock, the worker resumes execution, reiterating its while loop.
The Pulse and PulseAll methods release threads blocked on a Wait statement. Pulse releases a maximum of one thread; PulseAll releases them all.
In our example, just one thread is blocked, so their effects are identical. If more than one thread is waiting, calling PulseAll is usually safest with our suggested pattern of use.
In our pattern, pulsing indicates that something might have changed, and that waiting threads should recheck their blocking conditions.
In the Work method, this check is accomplished via the while loop. The waiter then decides whether to continue, not the notifier.
If pulsing by itself is taken as instruction to continue, the Wait construct is stripped of any real value; you end up with an inferior version of an AutoResetEvent. A race ensues between the main thread and the worker.
If Wait executes first, the signal works. If Pulse executes first, the pulse is lost and the worker remains forever stuck.Note: and older issues are only available regardbouddhiste.com files. On most versions of windows you must first save these files to your local machine, and then unblock the file in order to read it.
To unblock a file, right click on it, and select properties, and then select the ‘unblock’ button. Beginners guide to accessing SQL Server through C#. Matt Newman, 22 Aug ( votes) Introduction.
In this article I plan to demonstrate how to insert and read data from a SQL Server or MSDE database. This code should work on both SQL Server, I am using , and MSDE. As you can see the SqlDataReader does not access the.
Sep 13, · Building Windows Store apps with C# or VB I need to read/write data to an Microsoft Access database within my metro app, but if I am correct that is not possible? I want my service to be local, thats the point! All I need is to read data from a simple access database locally without any internet connection what so ever, I don.
You can read from (or write to) a text file using the Open statement, Close statement and various other statements for actually reading/writing. The Open statement has clauses for what type of access you want to the file, so you can specify if you want to read it as text, write to it as binary, and so on.
You can also set locking options, to stop other programs from opening the file. Note. A connection string is a string that specifies database connection information, such as the provider to use, the location of the database, authentication credentials, and other database-related settings.
For a list of connection string patterns used by a variety of data stores and providers, see regardbouddhiste.com A novel approach to developing and applying databases withVisual C#.NET. Practical Database Programming with Visual C#.NET clearlyexplains the considerations and applications in databaseprogramming with Visual C#.NET and in developing relationaldatabases such as Microsoft Access, SQL Server, and OracleDatabase.
Sidestepping the traditional approach of using .