Windows Workflow Foundation (8)-use activity control procedures and conditions for use in workflows

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Use Activity Control Process

Translated from: MS-help: // Ms. winwf. v1.en/winwf_gettingstarted/html/118e7847-de88-4cf1-a3ef-b344c231eb38.htm
 

WWFThe framework contains a set of activities. The relationship between activities and workflows is likeWindowsControls andFormThese activities provide a variety of functions. You can use these activities to control the logical flow of a workflow.

 

Listed belowWWFActivities in the framework that are commonly used to control logical flows.

 

Activity	description
listen	enables your workflow to contain a branch selected by the dependency event, or exit upon timeout.
ifelse	check the conditions of each branch in sequence, A branch meeting the conditions will be executed.
parallel	enables your workflow to process two or more irrelevant operations at the same time.
suspend	can suspend your workflow, to interfere with some events that contain error conditions.
terminate	enables your workflow to terminate immediately when an event with an error condition is received.
while	This allows your workflow to be executed cyclically, the conditions are unknown.
conditionedactivitygroup	also called CAG . executes child activities based on a condition that applies to the CAG itself, and based on conditions that apply separately to each child.
Eventdriven	This activity encapsulates other activities that run when a specified event occurs.

 

 

 

Conditions used in a Workflow

Translated from: MS-help: // Ms. winwf. v1.en/winwf_gettingstarted/html/41011f5-d382-4810-894f-71f00b34fa77.htm
 

You can use conditions to control workflow behaviors. The workflow engine determines the condition and then determines the behavior based on the judgment result.

There are two ways to express conditions in a workflow:

LYou can write a processing method and return a Boolean value.

LYou can define a rule in a workflow.

You can dynamically update Condition rules during workflow operation to change workflow behavior.

You can also create a policy-type activity to use conditional behavior.

 

Conditional Activity

 

L WWF provides the following conditions for use:

L ifelse activity branch, the result is based on the condition judgment.

LWhileThe activity continues to run cyclically, knowing that the condition is false.

L Conditionalactivitygroup The activity continues to execute its sub-activity until the condition is true. CAG Each independent sub-activity in the activity has a" When "Condition. Only When If the condition is true, the activity will be executed.

LReplicatorWhen the activity is judged to be true, its execution is completed.

You can use conditions in custom activities.

Note:

A condition rule can only be a variable or method that defines any public member in a workflow class. And ConditionCodeIt can be a public or private member.