c# elsa 自定义活动

nuget

Elsa 3.5.3

依赖注入

builder.Services.AddElsa();

基础流程创建

//需要注入对象
IWorkflowRunner workflowRunner;

//顺序工作流

var workflow = new Sequence();

workflow.Activities = new List<IActivity>();

for (int i = 0; i < 3; i++)
{
    workflow.Activities.Add(new WriteLine("test"));
}

var result = await workflowRunner.RunAsync(workflow);

//流程

var nameVariable = new Variable<string>();

// Define the activities to put in the flowchart:
var writeLine1 = new WriteLine("Please tell me your name:");
//var writeLine2 = new ReadLine(nameVariable);
var writeLine2 = new WriteLine(nameVariable);
var writeLine3 = new WriteLine(context => $"Nice to meet you, {nameVariable.Get(context)}!");
var cus = new TestActivity();

// Define a flowchart workflow:
var workflow = new Flowchart
{
    // Register the name variable.
    Variables = { nameVariable },

    // Add the activities.
    Activities =
    {
        writeLine1,
        writeLine2,
        writeLine3,
        cus
    },

    // Setup the connections between activities.
    Connections =
    {
        new Connection(writeLine1, writeLine2),
        new Connection(writeLine2, writeLine3),
        new Connection(writeLine3, cus)
    }
};

var result = await workflowRunner.RunAsync(workflow);

自定义活动

注册自定义活动

builder.Services.AddElsa(options => options.AddActivity<TestActivity>());

自定义活动

通过context.CompleteActivityAsync标记当前活动已经完成，可以直接执行后续的活动

   public class TestActivity : Activity //, IActivityWithResult
   {
       //public Output Result { get; set; } = new();

       //[Input] public Input<decimal> Amount { get; set; } = default!;
       //[Output] public Output<string> TransactionId { get; set; } = default!;

       /// <summary>
       /// 判断活动是否可以执行
       /// </summary>
       /// <param name="context"></param>
       /// <returns></returns>
       protected override ValueTask<bool> CanExecuteAsync(ActivityExecutionContext context)
       {
           //Console.WriteLine("CanExecuteAsync!");
           return ValueTask.FromResult(true);
           //return base.CanExecuteAsync(context);
       }

       /// <summary>
       /// 活动中执行的具体逻辑
       /// </summary>
       /// <param name="context"></param>
       /// <returns></returns>
       protected override ValueTask ExecuteAsync(ActivityExecutionContext context)
       {
           Console.WriteLine("活动已执行!");

           return context.CompleteActivityAsync();
       }
   }