TryLoadRunnableWorkflowCommand Class

.NET Framework (current version)

Represents the command that a workflow host executes against an instance store to load runnable instances in the persistence store into the memory.

Namespace:   System.Activities.DurableInstancing
Assembly:  System.Activities (in System.Activities.dll)


public sealed class TryLoadRunnableWorkflowCommand : InstancePersistenceCommand


Initializes an instance of the TryLoadRunnableWorkflowCommand class.


Indicates whether the command could attempt to acquire a lock on the instance. (Inherited from InstancePersistenceCommand.)


Returns a value that indicates whether the persistence provider may choose not to enlist in the ambient transaction (Transaction.Currnet) when executing this command. (Inherited from InstancePersistenceCommand.)


Gets the name of the persistence command.(Inherited from InstancePersistenceCommand.)


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Serves as the default hash function. (Inherited from Object.)


Gets the Type of the current instance.(Inherited from Object.)


Returns a string that represents the current object.(Inherited from Object.)


Validates the command.(Inherited from InstancePersistenceCommand.)

An instance is runnable, if it is not in the suspended state or the completed state and satisfies the following conditions:

  • The instance is unlocked and has a pending timer that has expired.

  • The instance is unlocked and its status is Executing.

  • The instance has an expired lock on it.

An instance store should periodically search for runnable instances that belong to a workflow host that uses the store. It should raise the HasRunnableWorkflowEvent when it finds a runnable instance in the persistence store that matches its workflow host type. If the instance store does not find a runnable instance in the persistence store, it should continue to monitor the persistence store for any runnable instances.

After raising the HasRunnableWorkflowEvent, the instance store should stop monitoring the persistence store for runnable instances until it receives and executes the TryLoadRunnableWorkflowCommand. The monitoring continues only if the TryLoadRunnableWorkflowCommand execution does not return any runnable instances.

When a workflow host receives the HasRunnableWorkflowEvent, it executes the TryLoadRunnableWorkflowCommand against the instance store to load the instance into the memory.

.NET Framework
Available since 4.0

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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