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WorkflowInvoker.Invoke Method (Activity)

Invokes a workflow synchronously using the specified workflow definition.

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

Public Shared Function Invoke ( _
	workflow As Activity _
) As IDictionary(Of String, Object)


Type: System.Activities.Activity
The workflow definition of the workflow to invoke.

Return Value

Type: System.Collections.Generic.IDictionary(Of String, Object)
A dictionary of the root activity’s OutArgument and InOutArgument values keyed by argument name that represent the outputs of the workflow.

This method blocks until the workflow has completed, including idle time. All workflow execution is guaranteed to execute on the invoking thread. To configure a time-out interval in which the workflow must complete, use one of the Invoke overloads that take a TimeSpan.

The following example invokes a workflow consisting of a single DiceRoll activity. The DiceRoll activity has two output arguments that represent the results of the dice roll operation. When the call to Invoke returns, each output argument is returned in the outputs dictionary, keyed by argument name.

public sealed class DiceRoll : CodeActivity
    public OutArgument<int> D1 { get; set; }
    public OutArgument<int> D2 { get; set; }

    static Random r = new Random();

    protected override void Execute(CodeActivityContext context)
        D1.Set(context, r.Next(1, 7));
        D2.Set(context, r.Next(1, 7));

IDictionary<string, object> outputs =
    WorkflowInvoker.Invoke(new DiceRoll());

Console.WriteLine("The two dice are {0} and {1}.",
    outputs["D1"], outputs["D2"]);

If the workflow's root activity has no output arguments or they are not needed by the host, they can be disregarded. The following example invokes a workflow consisting of a single WriteLine activity that does not have any output arguments.

Activity wf = new WriteLine
    Text = "Hello World."


.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.