19: Multithreading Patterns in C#

Creator PDF417 in C# 19: Multithreading Patterns
19: Multithreading Patterns
PDF417 Drawer In Visual C#
Using Barcode generator for .NET Control to generate, create PDF417 image in Visual Studio .NET applications.
SUMMARY
Bar Code Printer In Visual C#
Using Barcode generation for Visual Studio .NET Control to generate, create bar code image in Visual Studio .NET applications.
This chapter used a step-by-step approach to setting up both the asynchronous results pattern and the background worker pattern The asynchronous results pattern provides support for calling any method asynchronously, even a method written by a third party It includes a notification mechanism about method execution completion via a callback on a delegate passed when setting up the pattern One drawback to the asynchronous results pattern is that there is no inherent mechanism for posting the status of the asynchronous method However, the NET Framework 20 (and higher) provides this functionality in a second multithreading pattern called the background worker pattern The key about this pattern is that it includes support for notification of status (without polling), completion, and errors To support this, however, the pattern requires special code hooks within the asynchronously invoked method This prevents developers from using it on methods for which they have no source code, or if they are unwilling to code special hooks Calling long-running methods provided by third parties, for example, prevents the support for embedding the callback hooks within the methods The next chapter investigates another fairly complex NET technology: that of marshaling calls out of NET and into managed code using P/ Invoke In addition, it introduces a concept known as unsafe code, which is used to access memory pointers directly, as in C++
Creating PDF417 In .NET Framework
Using Barcode drawer for ASP.NET Control to generate, create PDF417 image in ASP.NET applications.
Platform Interoperability and Unsafe Code
PDF417 Creation In VS .NET
Using Barcode generation for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in .NET framework applications.
but sometimes it still isn t sufficient and you need to escape out of all the safety it provides and step back into the world of memory addresses and pointers C# supports this in three ways The first way is to go through Platform Invoke (P/Invoke) and calls into APIs exposed by unmanaged DLLs The second is through unsafe code, which enables access to memory pointers and addresses Frequently, code uses these features in combination The third way, which is not covered in this text, is through COM interoperability
PDF-417 2d Barcode Creator In VB.NET
Using Barcode creation for .NET Control to generate, create PDF-417 2d barcode image in .NET framework applications.
P/Invoke
Bar Code Drawer In C#.NET
Using Barcode creator for .NET Control to generate, create barcode image in VS .NET applications.
Declaring SafeHandle Calling
Paint Bar Code In C#.NET
Using Barcode drawer for Visual Studio .NET Control to generate, create bar code image in .NET framework applications.
HAS GREAT CAPABILITIES ,
Encoding Code 3 Of 9 In C#
Using Barcode creator for Visual Studio .NET Control to generate, create Code 39 Full ASCII image in .NET framework applications.
Platform Interoperability & Unsafe Code 2
Code 128 Code Set A Creation In C#.NET
Using Barcode printer for Visual Studio .NET Control to generate, create Code-128 image in .NET applications.
Unsafe Code Pointer Declaration Dereferencing a Pointer
Data Matrix Drawer In C#
Using Barcode drawer for VS .NET Control to generate, create Data Matrix image in .NET applications.
Pointers and Addresses
Generating Bar Code In Visual Basic .NET
Using Barcode maker for VS .NET Control to generate, create barcode image in Visual Studio .NET applications.
20: Platform Interoperability and Unsafe Code
Scanning Code-39 In VS .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in .NET framework applications.
This chapter culminates with a small program that determines whether the computer is a virtual computer The code requires that you do the following: 1 Call into an operating system DLL and request allocation of a portion of memory for executing instructions 2 Write some assembler instructions into the allocated area 3 Inject an address location into the assembler instructions 4 Execute the assembler code Aside from the P/Invoke and unsafe constructs covered here, the final listing demonstrates the full power of C# and the fact that the capabilities of unmanaged code are still accessible from C# and managed code
Bar Code Generator In Visual Studio .NET
Using Barcode creation for ASP.NET Control to generate, create bar code image in ASP.NET applications.
BEGINNER TOPIC What Is a Virtual Computer A virtual computer (or virtual machine), also called a guest computer, is virtualized or emulated through software running on the host operating system and interacting with the host computer s hardware For example, virtual computer software (such as VMWare Workstation and Microsoft Virtual PC) can be installed on a computer running a recent version of Windows Once the software is installed, users can configure a guest computer within the software, boot it, and install an operating system as though it was a real computer, not just one virtualized with software
Print Bar Code In .NET
Using Barcode creation for .NET framework Control to generate, create bar code image in Visual Studio .NET applications.
Platform Invoke
Make DataMatrix In Visual Studio .NET
Using Barcode generation for VS .NET Control to generate, create Data Matrix 2d barcode image in .NET applications.
Whether a developer is trying to call a library of his existing unmanaged code, accessing unmanaged code in the operating system not exposed in any managed API, or trying to achieve maximum performance for a particular algorithm that performs faster by avoiding the runtime overhead of type checking and garbage collection, at some point she must call into unmanaged code The CLI provides this capability through P/Invoke With P/Invoke, you can make API calls into exported functions of unmanaged DLLs
Printing GS1 - 13 In Java
Using Barcode generator for Java Control to generate, create European Article Number 13 image in Java applications.
Platform Invoke
Read Universal Product Code Version A In VS .NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
All of the APIs invoked in this section are Windows APIs Although the same APIs are not available on other platforms, developers can still use P/ Invoke for APIs native to their platform, or for calls into their own DLLs The guidelines and syntax are the same
UPC Symbol Printer In VS .NET
Using Barcode generator for .NET Control to generate, create UPC-A Supplement 2 image in .NET applications.
Declaring External Functions Once the target function is identified, the next step of P/Invoke is to declare the function with managed code Just like all regular methods that belong to a class, you need to declare the targeted API within the context of a class, but by using the extern modifier Listing 201 demonstrates how to do this
Painting Code 128 Code Set B In Visual Basic .NET
Using Barcode generator for VS .NET Control to generate, create Code 128B image in .NET framework applications.
Making UPC A In Java
Using Barcode generation for Java Control to generate, create UPC-A Supplement 5 image in Java applications.