elsa-core/src/activities/Elsa.Activities.ControlFlow/Activities/Switch.cs

using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Elsa.Attributes;
using Elsa.Expressions;
using Elsa.Extensions;
using Elsa.Results;
using Elsa.Services;
using Elsa.Services.Models;

namespace Elsa.Activities.ControlFlow.Activities
{
    [ActivityDefinition(
        Category = "Control Flow",
        Description = "Switch execution based on a given expression.",
        Icon = "far fa-list-alt",
        RuntimeDescription = "x => !!x.state.expression ? `Switch execution based on <strong>${ x.state.expression.expression }</strong>.` : x.definition.description",
        Outcomes = "x => x.state.cases.map(c => c.toString())"
    )]
    public class Switch : Activity
    {
        private readonly IWorkflowExpressionEvaluator expressionEvaluator;

        public Switch(IWorkflowExpressionEvaluator expressionEvaluator)
        {
            this.expressionEvaluator = expressionEvaluator;
            Cases = new List<string>();
        }

        [ActivityProperty(Hint = "The expression to evaluate. The evaluated value will be used to switch on.")]
        public WorkflowExpression<string> Expression
        {
            get => GetState<WorkflowExpression<string>>();
            set => SetState(value);
        }

        [ActivityProperty(Hint = "A comma-separated list of possible outcomes of the expression.")]
        public IReadOnlyCollection<string> Cases
        {
            get => GetState<IReadOnlyCollection<string>>();
            set => SetState(value);
        }

        protected override async Task<ActivityExecutionResult> OnExecuteAsync(
            WorkflowExecutionContext workflowContext,
            CancellationToken cancellationToken)
        {
            var result = await expressionEvaluator.EvaluateAsync(Expression, workflowContext, cancellationToken);
            return Outcome(result);
        }
    }
}