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barcode printing vb.net Part V in Visual C#
Part V PDF417 Printer In C#.NET Using Barcode encoder for .NET framework Control to generate, create PDF417 image in .NET framework applications. www.OnBarcode.comPDF417 Reader In C# Using Barcode scanner for .NET framework Control to read, scan read, scan image in VS .NET applications. www.OnBarcode.comThreading
Barcode Printer In Visual C#.NET Using Barcode encoder for .NET framework Control to generate, create bar code image in .NET framework applications. www.OnBarcode.comRecognize Barcode In C#.NET Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET applications. www.OnBarcode.com[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] private static extern Boolean SetThreadPriority( SafeWaitHandle hthread, ThreadBackgroundgMode mode); // http://msdn.microsoft.com/en-us/library/aa480216.aspx [DllImport("Kernel32", SetLastError = true, EntryPoint = "CancelSynchronousIo")] [return: MarshalAs(UnmanagedType.Bool)] private static extern Boolean CancelSynchronousIO(SafeWaitHandle hThread); } PDF-417 2d Barcode Creation In Visual Studio .NET Using Barcode generator for ASP.NET Control to generate, create PDF417 image in ASP.NET applications. www.OnBarcode.comPDF 417 Creation In .NET Using Barcode generator for VS .NET Control to generate, create PDF417 image in Visual Studio .NET applications. www.OnBarcode.comAnd here is code showing how to use it: PDF 417 Generation In Visual Basic .NET Using Barcode generator for .NET Control to generate, create PDF-417 2d barcode image in .NET framework applications. www.OnBarcode.comMatrix Barcode Printer In C#.NET Using Barcode creator for .NET framework Control to generate, create Matrix 2D Barcode image in Visual Studio .NET applications. www.OnBarcode.compublic static void Main () { using (ThreadIO.BeginBackgroundProcessing()) { // Issue low-priority I/O requests in here (eg: calls to BeginRead/BeginWrite) } } Printing Barcode In C#.NET Using Barcode generator for .NET Control to generate, create bar code image in VS .NET applications. www.OnBarcode.comMaking Code 128 Code Set C In Visual C# Using Barcode creator for Visual Studio .NET Control to generate, create Code 128 Code Set C image in VS .NET applications. www.OnBarcode.comYou tell Windows that you want your thread to issue low-priority I/O requests by calling ThreadIO s BeginBackgroundProcessing method . Note that this also lowers the CPU scheduling priority of the thread . You can return the thread to making normal-priority I/O requests (and normal CPU scheduling priority) by calling EndBackgroundProcessing or by calling Dispose on the value returned by BeginBackgroundProcessing (as shown above via C# s using statement) . A thread can only affect its own background processing mode; Windows doesn t allow a thread to change the background processing mode of another thread . If you want all threads in a process to make low-priority I/O requests and have low CPU scheduling, you can call BeginBackgroundProcessing, passing in true for the process parameter . A process can only affect its own background processing mode; Windows doesn t allow a thread to change the background processing mode of another process . Important As a developer, it is your responsibility to use these new background priorities to Universal Product Code Version A Generation In Visual C#.NET Using Barcode generation for .NET framework Control to generate, create UPC A image in .NET framework applications. www.OnBarcode.comGenerating ISBN - 13 In C# Using Barcode maker for Visual Studio .NET Control to generate, create ISBN image in .NET framework applications. www.OnBarcode.comallow the foreground applications to be more responsive, taking care to avoid priority inversion. In the presence of intense normal-priority I/Os, a thread running at background priority can be delayed for seconds before getting the result of its I/O requests . If a low-priority thread has grabbed a thread synchronization lock for which the normal-priority thread is waiting, the normal-priority threads might end up waiting for the background-priority thread until the low-priority I/O requests are completed . Your background-priority thread does not even have to submit I/Os for the problem to happen . So using shared synchronization objects between normal- and background-priority threads should be minimized (or eliminated if possible) to avoid these priority inversions where normal-priority threads are blocked on locks owned by background-priority threads . Generating Bar Code In Objective-C Using Barcode generation for iPhone Control to generate, create bar code image in iPhone applications. www.OnBarcode.comUPC-A Drawer In None Using Barcode generation for Office Excel Control to generate, create GTIN - 12 image in Office Excel applications. www.OnBarcode.com 27 I/O-Bound Asynchronous Operations
Decoding Bar Code In Java Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications. www.OnBarcode.comCode 128 Reader In Java Using Barcode decoder for Java Control to read, scan read, scan image in Java applications. www.OnBarcode.comConverting the IAsyncResult APM to a Task
UPC - 13 Generator In Java Using Barcode printer for Java Control to generate, create EAN-13 Supplement 5 image in Java applications. www.OnBarcode.comGenerate Barcode In Java Using Barcode drawer for Java Control to generate, create barcode image in Java applications. www.OnBarcode.comIn The APM and Compute-Bound Operations section earlier in this chapter, I showed how to use the APM to perform a compute-bound operation . In this section, I show how to do the opposite: use a Task to perform an I/O-bound operation . In the System.Threading.Tasks namespace, there is a class called TaskFactory . This class was discussed in 26 . However, this class offers a FromAsync method, which I did not discuss in 26 . This method accepts four arguments and returns a reference to a Task object . The four arguments are a BeginXxx method, an EndXxx method, an Object state, and an optional TaskCreationOptions10 value . So instead of initiating an asynchronous operation like this: Making Bar Code In VS .NET Using Barcode encoder for Reporting Service Control to generate, create bar code image in Reporting Service applications. www.OnBarcode.comPainting EAN / UCC - 13 In Java Using Barcode generator for Android Control to generate, create UCC-128 image in Android applications. www.OnBarcode.comWebRequest webRequest = WebRequest.Create("http://Wintellect.com/"); webRequest.BeginGetResponse(result => { WebResponse webResponse = null; try { webResponse = webRequest.EndGetResponse(result); Console.WriteLine("Content length: " + webResponse.ContentLength); } catch (WebException we) { Console.WriteLine("Failed: " + we.GetBaseException().Message); } finally { if (webResponse != null) webResponse.Close(); } }, null); you can turn it into a Task, and then use it with the rest of the Task infrastructure like this: WebRequest webRequest = WebRequest.Create("http://Wintellect.com/"); Task.Factory.FromAsync<WebResponse>( webRequest.BeginGetResponse, webRequest.EndGetResponse, null, TaskCreationOptions.None) .ContinueWith(task => { WebResponse webResponse = null; try { webResponse = task.Result; Console.WriteLine("Content length: " + webResponse.ContentLength); } catch (AggregateException ae) { if (ae.GetBaseException() is WebException) Console.WriteLine("Failed: " + ae.GetBaseException().Message); else throw; } finally { if (webResponse != null) webResponse.Close(); } }); 10 The FromAsync
method has additional overloads that allow you to pass up to three parameters to a BeginXxx method . If you need to call a BeginXxx method that takes more than three parameters, then there is a FromAsync overload that accepts an IAsyncResult parameter; you call the BeginXxx method yourself and its return value here . Avoid this overload if you can because it is less efficient than the overloads of FromAsync that do not take an IAsyncResult .
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