ArcGIS Engine Developer Guide

.NET APPLICATION PROGRAMMING INTERFACE
Assembly versioning and redirection
When new ArcGIS libraries are installed onto a machine, the corresponding
primary interop assemblies (PIA) are updated as well to ensure that the available
PIAs always correspond to the current libraries.
.NET applications that are built using a specific version of a strongly named
assembly will attempt to bind to the same version of that assembly at runtime
because a strong name includes the version number of the assembly.
To allow applications that bind to ArcGIS assemblies to find the new PIAs
without the need for developers to recompile against these new versions, ArcGIS
installs publisher policy files for each PIA. A publisher policy file is an assembly
that redirects the assembly binding process to use a new assembly version. These
policy files are installed to the general assembly cache (GAC) alongside the ESRI
PIAs.
For example, you will find the policy file policy.9.0.ESRI.ArcGIS.System.dll,
which redirects all assembly binding calls for the ESRI.ArcGIS.System.dll PIA
from all 9.0 and service pack assembly versions to the new current assembly
version.
Deploying an application using XCOPY will not
copy the settings in the machine configuration
file.
ARCGIS DEVELOPMENT USING .NET
Using .NET you can customize the ArcGIS applications, create standalone applications
that use ESRI’s types, and extend ESRI’s types. For example, you can
create a custom tool for ArcMap, a standalone application that uses the
MapControl, or a custom layer. This section discusses several key issues related to
developing with ArcGIS and .NET.
Registering .NET components with COM
Extending ArcGIS applications with custom .NET components requires registering
the components in the COM registry and exporting the .NET assemblies to a
type library (TLB). When developing a component, there are two ways to perform
this task: you can use the RegAsm utility that ships with the .NET Framework
SDK or Visual Studio .NET, which has a Register for COM Interop compiler
flag.
The example below shows an EditTools assembly being registered with COM.
The /tlb parameter specifies that a type library should also be generated and the
/codebase option indicates that the path to the assembly should be included in
the registry settings. Both of these parameters are required when extending the
ArcGIS applications with .NET components.
regasm EditTools.dll /tlb:EditTools.tlb /codebase
Visual Studio .NET performs this same operation automatically if you set the
Register for COM Interop compiler flag; this is the simplest way to perform the
registration on a development machine. To check a project’s settings, click Project
Properties from the Project menu, then look at the Build property under Configuration
Properties. The last item, Register for COM Interop, should be set to True.
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Registering .NET classes in COM component categories
Much of the extensibility of ArcGIS relies on COM component categories. In
fact, most custom ArcGIS components must be registered in component categories
appropriate to their intended context and function for the host application to