The finally Block in Visual C#.NET

Paint PDF-417 2d barcode in Visual C#.NET The finally Block

The finally Block
PDF417 Drawer In C#
Using Barcode maker for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in VS .NET applications.
www.OnBarcode.com
Recognize PDF-417 2d Barcode In Visual C#
Using Barcode scanner for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
A finally block contains code that s guaranteed to execute .2 Typically, the code in a finally block performs the cleanup operations required by actions taken in the try block .
Painting Bar Code In C#.NET
Using Barcode drawer for VS .NET Control to generate, create barcode image in VS .NET applications.
www.OnBarcode.com
Scanning Barcode In C#.NET
Using Barcode recognizer for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Aborting a thread or unloading an AppDomain causes the CLR to throw a ThreadAbortException, which allows the finally block to execute . If a thread is simply killed via the Win32 TerminateThread function, or if the process is killed via the Win32 TerminateProcess function or System.Environment s FailFast method, then the finally block will not execute . Of course Windows cleans up all resources that a process was using when a process terminates .
PDF-417 2d Barcode Printer In .NET Framework
Using Barcode generator for ASP.NET Control to generate, create PDF417 image in ASP.NET applications.
www.OnBarcode.com
PDF 417 Creation In VS .NET
Using Barcode drawer for .NET framework Control to generate, create PDF 417 image in Visual Studio .NET applications.
www.OnBarcode.com
20 Exceptions and State Management
PDF 417 Printer In VB.NET
Using Barcode drawer for .NET Control to generate, create PDF417 image in .NET applications.
www.OnBarcode.com
Code 128 Generation In Visual C#
Using Barcode generator for .NET framework Control to generate, create Code 128 Code Set B image in VS .NET applications.
www.OnBarcode.com
For example, if you open a file in a try block, you d put the code to close the file in a finally block:
UPC Symbol Generation In C#
Using Barcode creator for .NET framework Control to generate, create GS1 - 12 image in .NET applications.
www.OnBarcode.com
GS1-128 Printer In C#
Using Barcode maker for .NET Control to generate, create UCC - 12 image in Visual Studio .NET applications.
www.OnBarcode.com
private void ReadData(String pathname) { FileStream fs = null; try { fs = new FileStream(pathname, FileMode.Open); // Process the data in the file... } catch (IOException) { // Put code that recovers from an IOException here... } finally { // Make sure that the file gets closed. if (fs != null) fs.Close(); } }
EAN13 Drawer In C#.NET
Using Barcode maker for .NET framework Control to generate, create EAN / UCC - 13 image in .NET framework applications.
www.OnBarcode.com
USPS Confirm Service Barcode Generation In Visual C#.NET
Using Barcode generation for VS .NET Control to generate, create Planet image in .NET applications.
www.OnBarcode.com
If the code in the try block executes without throwing an exception, the file is guaranteed to be closed . If the code in the try block does throw an exception, the code in the finally block still executes, and the file is guaranteed to be closed, regardless of whether the exception is caught . It s improper to put the statement to close the file after the finally block; the statement wouldn t execute if an exception were thrown and not caught, which would result in the file being left open (until the next garbage collection) . A try block doesn t require a finally block associated with it; sometimes the code in a try block just doesn t require any cleanup code . However, if you do have a finally block, it must appear after any and all catch blocks . A try block can have no more than one finally block associated with it . When a thread reaches the end of the code contained in a finally block, the thread simply starts executing the statements immediately following the finally block . Remember that the code in the finally block is cleanup code . This code should execute only what is necessary to clean up operations initiated in the try block . The code inside catch and finally blocks should be very short and should have a high likelihood of succeeding without itself throwing an exception . Usually the code in these blocks is just one or two lines of code . It is always possible that exception-recovery code or cleanup code could fail and throw an exception . While possible, it is unlikely and if it does happen it usually means that there is something very wrong somewhere . Most likely some state has gotten corrupted somewhere . If an exception is inadvertently thrown within a catch or finally block, the world will not come to an end the CLR s exception mechanism will execute as though the exception were thrown after the finally block . However, the CLR does not keep track of the first exception that was thrown in the corresponding try block (if any), and you will lose any and all information (such as the stack trace) available about the first exception . Probably (and hopefully), this new exception will not be handled by your code and the exception will turn into an
Quick Response Code Creator In .NET
Using Barcode creation for Reporting Service Control to generate, create Quick Response Code image in Reporting Service applications.
www.OnBarcode.com
ECC200 Maker In Objective-C
Using Barcode drawer for iPhone Control to generate, create Data Matrix 2d barcode image in iPhone applications.
www.OnBarcode.com
Part IV
UCC - 12 Decoder In Visual C#
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Encoding PDF-417 2d Barcode In None
Using Barcode creator for Software Control to generate, create PDF417 image in Software applications.
www.OnBarcode.com
Core Facilities
Paint EAN13 In VB.NET
Using Barcode generator for .NET Control to generate, create EAN13 image in Visual Studio .NET applications.
www.OnBarcode.com
Barcode Generator In Java
Using Barcode printer for Eclipse BIRT Control to generate, create barcode image in BIRT applications.
www.OnBarcode.com
unhandled exception . The CLR will then terminate your process, which is good because all the corrupted state will now be destroyed . This is much better than having your application continue to run with unpredictable results and possible security holes . Personally, I think the C# team should have chosen different language keywords for the exception-handling mechanism . What programmers want to do is try to execute some piece of code . And then, if something fails, either recover from the failure and move on or compensate to undo some state change and continue to report the failure up to a caller . Programmers also want to have guaranteed cleanup no matter what happens . The code on the left is what you have to write to make the C# compiler happy, but the code on the right is the way I prefer to think about it:
Denso QR Bar Code Reader In Visual C#
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Make QR Code ISO/IEC18004 In Java
Using Barcode generator for Java Control to generate, create QR Code ISO/IEC18004 image in Java applications.
www.OnBarcode.com
void Method() { try { ... } catch (XxxException) { ... } catch (YyyException) { ... } catch { ...; throw; } finally { ... } }
void Method() { try { ... } handle (XxxException) { ... } handle (YyyException) { ... } compensate { ... } cleanup { ... } }
Copyright © OnBarcode.com . All rights reserved.