NET Framework 4. Many, but not all, of the new workflow features introduced in. For more information about the new features that are supported, see Support for New Workflow Foundation 4. For more information about migrating. NET Framework 3. This article provides an overview of the new workflow features introduced in. The new Windows Workflow Foundation features introduced in. If a project that targets. The file format is not compatible with current targeting framework.
To convert the file format, please explicitly save the file. This error message will go away after you save the file and reopen the designer. WorkflowIdentity provides workflow application authors a mechanism for mapping a persisted workflow instance with its definition. Developers using WorkflowApplication hosting can use WorkflowIdentity to enable hosting multiple versions of a workflow side-by-side.
Persisted workflow instances can be loaded using the new WorkflowApplicationInstance class, and then the DefinitionIdentity can be used by the host to provide the correct version of the workflow definition when instantiating the WorkflowApplication. WorkflowServiceHost is now a multi-version host. When a new version of a workflow service is deployed, new instances are created using the new service, but existing instances complete using the previous version. Dynamic update is introduced which provides a mechanism for updating the definition of a persisted workflow instance.
NET Framework 4 database scripts. This script updates. NET Framework 4 persistence databases to support the new versioning capabilities introduced in. The persisted workflow instances in the database are given default versioning values, and can participate in side-by-side execution and dynamic update.
For more information, see Upgrading. NoPersistScope is a new container activity that prevents a workflow from being persisted when the NoPersistScope's child activities are executing. This is useful in scenarios where it is not appropriate for the workflow to be persisted, such as when the workflow is using machine-specific resources such as file handles, or during database transactions.
Previously, to prevent persistence from occurring during an activity's execution, a custom NativeActivity that used a NoPersistHandle was required.
This will let the activity designer show more information about the activity's purpose. Flowcharts have a new property called ValidateUnconnectedNodes ; the default for this property is False. If this property is set to True , then unconnected flowchart nodes will produce validation errors. Workflows in. NET Framework 4 required a fully trusted application domain. In a partial trust environment, third-party components can be used without granting them full access to the resources of the host.
Some concerns about running workflows in partial trust are as follows:. This browser is no longer supported. Download Microsoft Edge More info. Contents Exit focus mode. Is this page helpful? Please rate your experience Yes No. Using WorkflowIdentity is easy. The following snippet shows how to use it with WorkflowApplication, our single-instance, single-definition, in-process host you just have to pass an instance of WorkflowIdentity to the constructor of WorkflowApplication :.
The next code sample shows how to use the identity to detect a version mismatch and to provide an actionable error message. This information can be used for logging or recovering from the error:.
Finally, you can learn the identity of a given workflow instance before loading it from the instance store. See bit. However, an unfortunate WF 4 limitation is that changes to the workflow definition result in an exception if you try to load a previously persisted instance into the WFSH.
This is because the host is unable to run these instances using the new definition this is the problem we noted in the WorkflowIdentity section. Some customers worked around the lack of built-in versioning support in WF 4 using multiple WFSHs and a WCF routing service as an intermediary between the client app and the workflows.
Clients send messages to the router, which routes the messages to the corresponding WFSH configured with the right version of the definition. The downside is that this requires the client application to be version-aware to successfully send messages to a service instance. The semantics are very simple: New instances start with the latest version of the service, and running instances continue executing with the version used to start them.
The key enabler for this feature is WorkflowIdentity. To determine the version of a service definition you need to configure its identity. Alternatively, old versions can also be loaded explicitly into the WorkflowServiceHost by adding to the SupportedVersions collection prior to opening the host.
They just send a message; the usual correlation mechanism resolves it to the right instance and the host uses the corresponding definition because the persisted instance state contains the identity of the definition needed to load it.
This feature is also available in self-hosting scenarios hosting WFSH in your own app. This is often a problem when programs need to be updated due to bug fixes or changing requirements. Our enterprise customers were emphatic about the importance of this capability, because they often need to change a particular workflow instance in long-running workflows. For example, suppose a workflow that models an interview process has four interviewers but, given a new company policy, now needs to be changed to add a fifth interviewer.
You can in WF 4. Dynamic Update allows you to make changes to a running instance of a workflow to accommodate a new workflow definition. Such changes might be motivated by omissions at design time, bugs in the workflow, or new requirements. In that sort of case, you should design a new workflow instead of making changes to a running instance. Dynamic Update is generally a two-step process: When changing the workflow definition, you also need to create an update map: a structure that contains information about the changes.
When the new version is deployed, the map can be used to update running instances to the new definition. It supports updating activities, providing custom update semantics, emitting tracking information and more. It gives you a rich API you can use in your applications to provide update capabilities for your running instances. I want to briefly describe some runtime enhancements in WF 4.
Partial Trust WF 4 requires full-trust to execute. We also exposed fast-path capabilities that can be used with code activities for authoring expression activities with better performance. Starting with. This feature is supported in the rehosted designer. Since a workflow or certain container activities such as NoPersistScope can only contain a single body activity, adding a second activity required the developer to delete the first activity, add a Sequence activity, and then add both activities to the sequence activity.
The following screenshot shows the automatically created Sequence activity in the Body when a second WriteLine is dropped below the first. To more easily navigate a large workflow in the designer, pan mode can be enabled, allowing the developer to click and drag to move the visible portion of the workflow, rather than needing to use the scroll bars. The button to activate pan mode is in the lower right corner of the designer. The following screenshot shows the pan button which is located at the bottom right corner of the workflow designer.
Multiple activities can be selected at one time, either by dragging a rectangle around them when pan mode is not enabled , or by holding down Ctrl and click on the desired activities one by one. Multiple activity selections can also be dragged and dropped within the designer, and can also be interacted with using the context menu.
In order to make hierarchical workflows easier to navigate, components of a workflow are shown in a tree-style outline view. The outline view is displayed in the Document Outline view. Clicking on a node in outline view will navigate to the corresponding activity in the workflow designer, and the outline view will be updated to show activities that are selected in the designer.
The following screenshot of the completed workflow from the Getting Started Tutorial shows the outline view with a sequential workflow. In a rehosted designer, some of the standard UI controls may not have meaning for a given workflow, and may be turned off. NET Framework 4, this customization is only supported by the shell bar at the bottom of the designer.
NET Framework 4, connections between nodes in a Flowchart workflow had to be added manually. Dropping an activity on one of these points automatically adds the activity along with the necessary connection.
The following screenshot shows the attachment points that become visible when an activity is dragged from the toolbox. Activities can also be dragged onto connections between flowchart nodes and states to auto-insert the node between two other nodes. The following screenshot shows the highlighted connecting line where activities can be dragged from the toolbox and dropped.
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