You cannot perform some operations directly in an orchestration; for example, accessing individual fields of an array, string replacement functions and accessing external web services. To perform such operations, you can use external C# code. The following activities are available for defining and using the external code with an orchestration process.
| Activity | Explanation |
|---|---|
| ExternalProcess | Provides the ability to name the external process and declare the parameters to the process. |
| CallProcess | Provides the ability to specify the process name to call and assign the parameters to pass to the process. |
When you save an orchestration containing ExternalProcess activities, the solution searches for a project named <datasourcename>Extensions, where <datasourcename> is the name of the data source. If the project is not found, it is created. This project implements the external process methods and provides references to the orchestration, client, and server messages. Additionally, the project provides methods to perform various tasks such as InvokeServer or copying a server message to a client message.
The project includes references to the associated data source project, Unisys.Common.EISConnectors (defines EISRecord and EISField), and Unisys.Common.Runtime (defines Orchestration Exceptions).
Passing Parameters to an External Process
When you call an external process from orchestration, its parameters receive variables from servers or clients.
Note: The parameters can also be local variables, calculation, and literals.
You can pass these local variables, calculation or literals to an external process.
To pass a local variable to an external process, perform the following steps:
Drag CallProcess to the client message and assign the defined external process.
Define the local variable in the declaration part of the message and assign it to the call process.
Add the external process reference to the presentation project and run the presentation project.
When the external process is called, it will also receive the defined local variables.
To pass a calculation or literal to an external process, perform the following steps:
In the Toolbox window, drag Assign from the Basic Activities, and then assign a literal to the defined local variable.
In the Assign Data for Message Local.var window, select Calculation or Literal from the Assign From list, and then click OK.
The values are assigned and passed to the External Process.
For more information on the following, refer to Using the OrchExtensions Class:
Accessing session declarations defined in the orchestration
Interacting with the data source connector
Interacting with the client
Accessing orch.Message
Notes:
Presentation projects that are using this data source must manually add a reference to the <datasourcename>Extensions project.
If your extensions require configuration such as an App.config file for an external webservice, you must manually incorporate the data in the Web.config file of the web project. For information on modifying the webservice configuration, refer Modifying the Web.config File.