CUSTOM ATTRIBUTES in VB.NET

Creator PDF417 in VB.NET CUSTOM ATTRIBUTES

CHAPTER 16 CUSTOM ATTRIBUTES
Draw PDF417 In VB.NET
Using Barcode drawer for .NET Control to generate, create PDF 417 image in Visual Studio .NET applications.
www.OnBarcode.com
PDF417 Decoder In VB.NET
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
// Class's custom attribute .custom instance void System.Runtime.InteropServices.GuidAttribute::.ctor(string) = ( 01 00 24 34 39 36 42 30 41 42 45 2D 43 44 45 45 2D 31 31 64 33 2D 38 38 45 38 2D 30 30 39 30 32 37 35 34 43 34 33 41 00 00 ) .method public hidebysig newslot virtual abstract instance class System.Collections.IEnumerator GetEnumerator() { // Method's custom attribute .custom instance void System.Runtime.InteropServices.DispIdAttribute::.ctor(int32) = ( 01 00 FC FF FF FF 00 00 ) ... } // End of method IEnumerable::GetEnumerator ... } // End of class IEnumerable ... This is in stark contrast to the way custom attributes are declared, for instance, in C# where a custom attribute belonging to an item immediately precedes the item declaration. For example, the following is an excerpt showing the C# declaration of the interface IEnumerable mentioned in the preceding code: [Guid("496B0ABE-CDEE-11d3-88E8-00902754C43A")] public interface IEnumerable { [DispId(-4)] IEnumerator GetEnumerator(); } The ILAsm rule specifying that custom attribute ownership is defined by the position of the attribute declaration can play tricks on you if you don t pay attention. Don t forget that when a declaration of a nonscoped item is encountered within the scope of another item, the custom attribute s ownership immediately switches to this newly declared item. Because of that, the custom attributes belonging to a scoped item cannot be declared just anywhere within the item s scope. The following code snippet illustrates the point: .class public MyClass { .custom instance void MyClassAttribute::.ctor()=(01 00 00 00) .field int32 MyField .custom instance void MyFieldAttribute::.ctor()=(01 00 00 00) .method public int32 MyMethod([opt]int32 J) { .custom instance void MyMethodAttribute::.ctor()=(01 00 00 00) .param[1] = int32(123456) .custom instance void MyParamAttribute::.ctor()=(01 00 00 00)
Drawing Barcode In VB.NET
Using Barcode encoder for .NET framework Control to generate, create Barcode image in .NET applications.
www.OnBarcode.com
Painting 1D Barcode In VB.NET
Using Barcode generation for VS .NET Control to generate, create 1D Barcode image in .NET applications.
www.OnBarcode.com
CHAPTER 16 CUSTOM ATTRIBUTES
EAN128 Generation In Visual Basic .NET
Using Barcode creator for .NET Control to generate, create UCC-128 image in Visual Studio .NET applications.
www.OnBarcode.com
DataMatrix Creator In Visual Basic .NET
Using Barcode printer for .NET framework Control to generate, create Data Matrix ECC200 image in .NET framework applications.
www.OnBarcode.com
... } } To avoid possible confusion about the ownership of a custom attribute, it s better to declare an item s custom attributes as soon as the item s scope is opened, before any other items are declared within the scope. The preceding discussion covers the rules for assigning custom attributes to items that are declared explicitly. Obviously, these rules cannot be applied to metadata items, which are declared implicitly, simply by their appearance in ILAsm directives and instructions. After all, such metadata items as TypeRefs, TypeSpecs, and MemberRefs might want their fair share of custom attributes, too. To resolve this problem, ILAsm offers another (full) form of the custom attribute declaration, with the explicit specification of the custom attribute owner: .custom ( <owner_spec> ) instance void <class_ref>::.ctor(<arg_list>) [ = ( <hexbytes> ) ] where <owner_spec> ::= <class_ref> | <type_spec> | method <method_ref> | field <field_ref> For example: .custom ([mscorlib]System.String) instance void MyTypeRefAttribute::.ctor()=(01 00 00 00) .custom ([mscorlib]System.String[]) instance void MyTypeSpecAttribute::.ctor()=(01 00 0 0 00) .custom (method instance void [OtherAssem]Foo::Bar(int32,int32)) instance void MyMemberRefAttribute1::.ctor()=(01 00 00 00) .custom (field int32 [.module OtherMod]Foo::Baz) instance void MyMemberRefAttribute2::.ctor()=(01 00 00 00) Custom attribute declarations in their full form can appear anywhere within the ILAsm source code, because the owner of a custom attribute is specified explicitly and doesn t have to be inferred from the positioning of the custom attribute declaration. The IL disassembler puts the custom attribute declarations in full form at the end of the source code dump, before the data dump. Note that version 2.0 of the IL assembler also supports the verbal description of custom attribute values in the full form of custom attribute declaration. Two additional categories of metadata items can in principle own custom attributes: InterfaceImpls and StandAloneSigs. The existing releases of ILAsm offer no language means to define custom attributes belonging to these items, an omission to be corrected in future revisions of ILAsm and its compiler. Of course, so far no compiler or other tool has generated custom attributes for these items, but you never know. The tools develop quickly, and the custom attributes proliferate even more quickly, so sooner or later somebody will manage to assign a custom attribute to an interface implementation or a stand-alone signature.
Code-39 Encoder In Visual Basic .NET
Using Barcode creator for .NET framework Control to generate, create Code 39 Extended image in Visual Studio .NET applications.
www.OnBarcode.com
Make Leitcode In VB.NET
Using Barcode printer for VS .NET Control to generate, create Leitcode image in .NET framework applications.
www.OnBarcode.com
PDF417 Encoder In None
Using Barcode creation for Office Word Control to generate, create PDF 417 image in Microsoft Word applications.
www.OnBarcode.com
PDF417 Generation In .NET
Using Barcode printer for ASP.NET Control to generate, create PDF 417 image in ASP.NET applications.
www.OnBarcode.com
Making Matrix Barcode In Visual C#
Using Barcode printer for VS .NET Control to generate, create Matrix image in .NET framework applications.
www.OnBarcode.com
Denso QR Bar Code Maker In None
Using Barcode creator for Font Control to generate, create QR Code 2d barcode image in Font applications.
www.OnBarcode.com
EAN 128 Creator In Visual Studio .NET
Using Barcode creator for .NET framework Control to generate, create EAN 128 image in VS .NET applications.
www.OnBarcode.com
Scan Barcode In VB.NET
Using Barcode scanner for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Print Code39 In Java
Using Barcode generation for Android Control to generate, create Code 39 image in Android applications.
www.OnBarcode.com
Quick Response Code Generation In .NET
Using Barcode maker for Reporting Service Control to generate, create QR-Code image in Reporting Service applications.
www.OnBarcode.com
Universal Product Code Version A Creation In None
Using Barcode printer for Font Control to generate, create UPC Symbol image in Font applications.
www.OnBarcode.com
Code 39 Drawer In None
Using Barcode encoder for Font Control to generate, create Code-39 image in Font applications.
www.OnBarcode.com
Barcode Generation In VS .NET
Using Barcode generator for Reporting Service Control to generate, create Barcode image in Reporting Service applications.
www.OnBarcode.com
Printing EAN-13 In Java
Using Barcode creator for Java Control to generate, create European Article Number 13 image in Java applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.