code 39 vb.net domain neutral fashion. Assemblies loaded this way can t be unloaded until the process terminates. in .NET framework

Create Code 3 of 9 in .NET framework domain neutral fashion. Assemblies loaded this way can t be unloaded until the process terminates.

domain neutral fashion. Assemblies loaded this way can t be unloaded until the process terminates.
Encoding USS Code 39 In .NET
Using Barcode creation for ASP.NET Control to generate, create ANSI/AIM Code 39 image in ASP.NET applications.
www.OnBarcode.com
Making Bar Code In VS .NET
Using Barcode generation for ASP.NET Control to generate, create barcode image in ASP.NET applications.
www.OnBarcode.com
Figure 20 1 : A single Windows process hosting the CLR and two AppDomains
Generate USS Code 39 In C#.NET
Using Barcode creator for .NET Control to generate, create USS Code 39 image in .NET applications.
www.OnBarcode.com
Create Code-39 In .NET Framework
Using Barcode encoder for .NET Control to generate, create USS Code 39 image in .NET framework applications.
www.OnBarcode.com
Accessing Objects Across AppDomain Boundaries
Code39 Printer In VB.NET
Using Barcode maker for .NET framework Control to generate, create USS Code 39 image in VS .NET applications.
www.OnBarcode.com
Encoding PDF-417 2d Barcode In Visual Studio .NET
Using Barcode printer for ASP.NET Control to generate, create PDF-417 2d barcode image in ASP.NET applications.
www.OnBarcode.com
Code in one AppDomain can communicate with types and objects contained in another AppDomain. However, the access to these types and objects is only through well defined mechanisms. Most types are marshaled by value across AppDomain boundaries. In other words, if an object is constructed in one AppDomain and a reference to this object is passed to another AppDomain, the CLR must first serialize the object s fields into a block of memory. This block of memory is then passed to the other AppDomain, which deserializes the block to produce a new object. The destination AppDomain uses the reference to this new object. The destination AppDomain has no access to the original AppDomain s object. For objects to be remoted by value, the object s type must have the System.Serializable custom attribute applied to it. Note Deserializing an object causes the CLR to load the type s assembly if necessary. If the CLR can t locate the assembly using the destination AppDomain s policies (for example, the AppDomain can have a different AppBase directory), the object can t be deserialized and an exception will be thrown.
Print EAN 128 In .NET
Using Barcode generator for ASP.NET Control to generate, create EAN / UCC - 13 image in ASP.NET applications.
www.OnBarcode.com
Generating 2D Barcode In .NET
Using Barcode creation for ASP.NET Control to generate, create Matrix 2D Barcode image in ASP.NET applications.
www.OnBarcode.com
Types that are derived from System.MarshalByRefObject can also be accessed across AppDomain boundaries. However, access to the object is accomplished by reference rather than by value. Let s say that an AppDomain has an object created in it whose type is derived from MarshalByRefObject. When a reference to this object is passed to a destination AppDomain, the 396
Create UPC-A Supplement 2 In .NET
Using Barcode printer for ASP.NET Control to generate, create UPC-A Supplement 2 image in ASP.NET applications.
www.OnBarcode.com
Paint Barcode In VS .NET
Using Barcode printer for ASP.NET Control to generate, create barcode image in ASP.NET applications.
www.OnBarcode.com
CLR actually creates an instance of a proxy type in the destination AppDomain, and a reference to this proxy object is what code in the destination AppDomain will use. The original object and its fields remain in the original AppDomain. The proxy object is a wrapper that knows how to call instance methods on the original object in the original AppDomain. Again, the destination doesn t have direct access to the original AppDomain s object. Obviously, accessing objects across AppDomain boundaries has some performance costs associated with it. When possible, you should avoid manipulating objects across AppDomain boundaries. A one to one correspondence doesn t exist between threads and AppDomains. When a thread in one AppDomain calls a method in another AppDomain, the thread transitions between the two AppDomains. This means that method calls across AppDomain boundaries are executed synchronously. However, at any given time, a thread is considered to be in just one AppDomain. You can call System.Threading.Thread s static GetDomain method to obtain a reference to the System.AppDomain object to identify the AppDomain that the thread is currently executing in. When unloading an AppDomain, the CLR knows which threads are in the AppDomain, and the CLR forces a ThreadAbortException exception in the threads so that they unwind out of the AppDomain. Once the threads have left the AppDomain, the CLR can invalidate all proxy objects that refer to objects in the unloaded AppDomain. At this point, any calls to methods using an invalid proxy will cause a System.AppDomainUnloadedException exception to be thrown because the original object no longer exists. The AppDomainRunner sample application discussed in this chapter s Explicitly Unloading Assemblies: Unloading an AppDomain section demonstrates how to marshal an object by reference across an AppDomain boundary.
Making EAN-13 Supplement 5 In VS .NET
Using Barcode generator for ASP.NET Control to generate, create EAN-13 image in ASP.NET applications.
www.OnBarcode.com
OneCode Generator In VS .NET
Using Barcode generator for ASP.NET Control to generate, create OneCode image in ASP.NET applications.
www.OnBarcode.com
AppDomain Events
Bar Code Reader In .NET Framework
Using Barcode Control SDK for ASP.NET Control to generate, create, read, scan barcode image in ASP.NET applications.
www.OnBarcode.com
Bar Code Decoder In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
I want to briefly mention that each AppDomain exposes a number of events that can be incredibly useful. Table 20 1 lists the events that your code can register interest in. Table 20 1: AppDomain Events Event Name AssemblyLoad Description This event is fired every time the CLR loads an assembly into the AppDomain. The handler receives a System.Reflection.Assembly object identifying the loaded assembly. This event is fired just before the AppDomain is unloading. This event isn t fired when the process containing the AppDomain is terminating. This event is fired just before the process terminates. This event is fired only for the default AppDomain; any other AppDomain that registers interest in this event won t receive a notification. This event is fired when an unhandled exception occurs in an AppDomain. This event is covered in 18. This event is fired when the CLR can t locate an assembly required by the AppDomain. The handler receives a string 397
Print EAN / UCC - 13 In None
Using Barcode generation for Font Control to generate, create EAN 128 image in Font applications.
www.OnBarcode.com
Barcode Reader In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
www.OnBarcode.com
Denso QR Bar Code Maker In Objective-C
Using Barcode encoder for iPhone Control to generate, create QR Code image in iPhone applications.
www.OnBarcode.com
Reading Code 128A In VB.NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Scan Barcode In Visual Basic .NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
UPC-A Supplement 2 Maker In .NET Framework
Using Barcode creation for Reporting Service Control to generate, create UPC-A image in Reporting Service applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.