decision.md

Decision

The Decision activity models a decision that yields a true or a false outcome, and is analogous to C#'s if statement.

Inputs

Name	Type	Description
Condition	Input<bool>	An expression that evaluates to a boolean value

Outcomes

Name	Description
True	Triggered when the condition evaluates to true
False	Triggered when the condition evaluates to false

Usage

The following workflow shows an example of how the Decision activity can be used inside a Flowchart activity.

{% code fullWidth="false" %}

using Elsa.Workflows;
using Elsa.Workflows.Activities;
using Elsa.Workflows.Activities.Flowchart.Activities;
using Elsa.Workflows.Contracts;
using Endpoint = Elsa.Workflows.Activities.Flowchart.Models.Endpoint;

namespace ElsaServer.Workflows;

public class FlowDecisionWorkflow : WorkflowBase
{
    protected override void Build(IWorkflowBuilder builder)
    {
        builder.Name = "Flow Decision Workflow";

        var age = builder.WithVariable<int>();
        var promptWriteLine = new WriteLine("What is your age?");
        var readLine = new ReadLine(age);
        var isAdult = new FlowDecision(context => age.Get(context) >= 18);
        var adult = new WriteLine("You are an adult.");
        var minor = new WriteLine("You are a minor.");
        var finish = new Finish();

        builder.Root = new Flowchart
        {
            Activities =
            {
                promptWriteLine,
                readLine,
                isAdult,
                adult,
                minor,
                finish
            },
            Connections =
            {
                new(promptWriteLine, readLine),
                new(readLine, isAdult),
                new(new Endpoint(isAdult, "True"), new Endpoint(adult)),
                new(new Endpoint(isAdult, "False"), new Endpoint(minor)),
                new(new Endpoint(adult), new Endpoint(finish)),
                new(new Endpoint(minor), new Endpoint(finish))
            }
        };
    }
}

{% endcode %}