vb.net 2008 barcode generator What s in an Exception in Visual C#

Draw PDF 417 in Visual C# What s in an Exception

What s in an Exception
PDF-417 2d Barcode Creation In C#
Using Barcode drawer for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Recognize PDF-417 2d Barcode In Visual C#
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
A .NET Framework exception contains useful information that captures information about what triggered the exception and how to address the problem. For example, the exception source is stored as a string in the Source property; a text representation of the call stack is included in the form of the StackTrace property; and there s a Message property, which contains a message suitable for display to a user. It s use is demonstrated in Listing 10-2.
Draw UPC Code In C#.NET
Using Barcode encoder for Visual Studio .NET Control to generate, create UPC A image in .NET applications.
www.OnBarcode.com
Barcode Creator In C#.NET
Using Barcode generation for .NET framework Control to generate, create Barcode image in .NET framework applications.
www.OnBarcode.com
CHAPTER 10 EXCEPTIONS, ATTRIBUTES, AND REFLECTION
EAN-13 Generator In C#.NET
Using Barcode maker for .NET framework Control to generate, create EAN-13 Supplement 5 image in .NET applications.
www.OnBarcode.com
Barcode Generation In C#.NET
Using Barcode encoder for .NET framework Control to generate, create Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Listing 10-2. Using the Properties of the Exception Class // exception_properties.cpp using namespace System; int main() { try { bool error = true; // other code if (error) { throw gcnew Exception("XYZ"); } } catch( Exception^ exception) { Console::WriteLine("Exception Source property {0}", exception->Source); Console::WriteLine("Exception StackTrace property {0}", exception->StackTrace); Console::WriteLine("Exception Message property {0}", exception->Message); } } The output of Listing 10-2 is as follows: Exception Source property exception_properties Exception StackTrace property at main() Exception Message property XYZ When an unhandled exception occurs in a console application, the Message and StackTrace data are printed to the standard error stream, like this: Unhandled Exception: System.Exception: XYZ at main() There s also a property of the Exception class called InnerException, which may reference an exception that gives rise to the exception we re looking at. In this way, a cascading series of exceptions may be nested one within the other. This could be useful if an exception occurs deep down in low-level code, but there are several layers of libraries between the problem and the code that knows how to handle such situations. As a designer of one of the intermediate libraries, you could choose to wrap that lower exception as an inner exception and throw a higher exception of a type that is more intelligible to your clients. By passing the inner exception,
Making PDF 417 In Visual C#.NET
Using Barcode generator for VS .NET Control to generate, create PDF417 image in .NET framework applications.
www.OnBarcode.com
International Standard Serial Number Generation In Visual C#
Using Barcode generation for .NET framework Control to generate, create ISSN image in .NET applications.
www.OnBarcode.com
CHAPTER 10 EXCEPTIONS, ATTRIBUTES, AND REFLECTION
PDF-417 2d Barcode Decoder In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Scan PDF-417 2d Barcode In VB.NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
the inner exception information can be used by the error-handling code to respond more appropriately to the real cause of the error.
GTIN - 13 Recognizer In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
DataMatrix Scanner In Visual Studio .NET
Using Barcode recognizer for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Creating Exception Classes
Generating Barcode In Objective-C
Using Barcode encoder for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
Barcode Scanner In Java
Using Barcode Control SDK for Eclipse BIRT Control to generate, create, read, scan barcode image in BIRT applications.
www.OnBarcode.com
You will often want to create your own exception classes specific to particular error conditions; however, you should avoid doing this and use one of the standard Exception classes, if possible. Writing your own exception class lets you filter on and write exception handlers specific to that error. To do this, you may derive from System::Exception. You would normally override the Message property in the Exception base class to deliver a more relevant error message (see Listing 10-3). Listing 10-3. Creating a Custom Exception // exceptions_custom.cpp using namespace System; ref class MyException : Exception { public: virtual property String^ Message { String^ get() override { return "You must supply a command-line argument."; } } }; int main(array<String^>^ args) { try { if (args->Length < 1) { throw gcnew MyException(); } throw gcnew Exception(); } // The first catch blocks are the specific exceptions that // you are looking for. catch (MyException^ e) { Console::WriteLine("MyException occurred! " + e->Message); }
Barcode Reader In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Drawing Barcode In .NET
Using Barcode creator for Visual Studio .NET Control to generate, create Barcode image in .NET applications.
www.OnBarcode.com
CHAPTER 10 EXCEPTIONS, ATTRIBUTES, AND REFLECTION
EAN 128 Generator In Java
Using Barcode generation for Android Control to generate, create EAN 128 image in Android applications.
www.OnBarcode.com
Scan USS Code 128 In .NET
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
// You may also catch other exceptions with multiple try blocks, // although it's better. catch (Exception^ exception) { Console::WriteLine("Unknown exception!"); } } The output of Listing 10-3 (with no command-line arguments) is shown here:
Generate Code128 In Objective-C
Using Barcode drawer for iPhone Control to generate, create Code 128 Code Set A image in iPhone applications.
www.OnBarcode.com
Generate UCC - 12 In Java
Using Barcode creator for BIRT reports Control to generate, create UCC - 12 image in Eclipse BIRT applications.
www.OnBarcode.com
MyException occurred! You must supply a command-line argument.
Using the Finally Block
C++/CLI recognizes the finally contextual keyword, which is a feature of other languages that support exception handling such as Java and C#. The finally keyword precedes a block of code known as a finally block. Finally blocks appear after catch blocks and execute whether or not an exception is caught. Use a finally block (see Listing 10-4) to put any cleanup code that you don t want to duplicate in both the try block and the catch blocks. The syntax is like that in other languages. Listing 10-4. Using a Finally Block try { // ... } catch( Exception^ ) { } finally { Console::WriteLine("finally block!"); } In the case of multiple finally blocks, they are executed from the inside out as demonstrated in Listing 10-5. Listing 10-5. Using Multiple Finally Blocks // multiple_finally_blocks.cpp using namespace System;
Copyright © OnBarcode.com . All rights reserved.