C#

static void Main(string[] args)
{
    new Program();
    Console.ReadLine();
}

public Program()
{
    DoIt();
}

public async void DoIt()
{
    AlarmReceived += () => new Task(() => Console.WriteLine("A"));
    AlarmReceived += () => new Task(() => Console.WriteLine("B"));
    await OnAlarm();
}

AlarmReceived += () => Task.Run(() => Console.WriteLine("A"));
AlarmReceived += () => Task.Run(() => Console.WriteLine("B"));

static void Main(string[] args)
{
    new Program();
    Console.ReadLine();
}

public Program()
{
    DoIt2();
    Console.WriteLine("Waiting for alarms to process...");
}

List<Action> alarmActions = new List<Action>();

public void AddAlarm(Action act)
{
    alarmActions.Add(act);
}

public void RemoveAlarm(Action act)
{
    alarmActions.Remove(act);
}

public async void DoIt2()
{
    Console.WriteLine("Adding alarms");
    AddAlarm(() => Alarm1());
    AddAlarm(() => Alarm2());
    await Task.Run(() => ProcessAlarms());
    Console.WriteLine("Removing alarms");
    RemoveAlarm(() => Alarm1());
    RemoveAlarm(() => Alarm2());
    await Task.Run(() => ProcessAlarms());
}

public void ProcessAlarms()
{
    alarmActions.ForEach(a => a());
}

public void Alarm1()
{
    System.Threading.Thread.Sleep(1000);
    Console.WriteLine("Alarm 1");
}

public void Alarm2()
{
    Console.WriteLine("Alarm 2");
}

Action a = () => Alarm1();
Action b = () => Alarm2();
Console.WriteLine("Adding alarms");
AddAlarm(a);
AddAlarm(b);
await Task.Run(() => ProcessAlarms());
Console.WriteLine("Removing alarms");
RemoveAlarm(a);
RemoveAlarm(b);
await Task.Run(() => ProcessAlarms());

Task a = Task.Run(() =>
{
    System.Threading.Thread.Sleep(1000);
    Console.WriteLine("A");
}));

AlarmReceived += () => a;

        public async void DoIt()
        {
            Task a = Task.Run(() =>
            {
                System.Threading.Thread.Sleep(1000);
                Console.WriteLine("A");
            });

<pre>
        Task b = Task.Run(() => Console.WriteLine("B"));

        AlarmReceived += () => a;
        AlarmReceived += () => b;
        Console.WriteLine("Processing alarms");
        await OnAlarm();

        Console.WriteLine("Unwire");
        AlarmReceived -= () => a;
        AlarmReceived -= () => b;
        await OnAlarm();
    }

    internal async Task OnAlarm()
    {
        if (eAlarmReceived == null)
        {
            Console.WriteLine("eAlarmReceived is null!");
            return;
        }

        // REMARK: ToList() to capture the event list at the moment of the call
        var eTasks = eAlarmReceived.GetInvocationList().Cast<Func<Task>>().ToList();

        if (eTasks.Count == 0)
        {
            Console.WriteLine("Nothing to do!");
        }
        else
        {
            Console.WriteLine("Tasks = " + eTasks.Count);
            foreach (var t in eTasks)
                await t();
        }
    }</pre>

Processing alarms
B
Tasks = 2
Waiting for alarms to process...
A
Unwire
Tasks = 2

Marc Clifton wrote:

But again, the use of the anonymous method for AlarmReceived means you can't unwire it.

    class AlarmSource
    {
        public async Task OnAlarm()
        {
            var eTasks = AlarmReceived?.GetInvocationList()?.Cast<Func<Task>>()?.ToList();
            if (eTasks == null)
                return;
            foreach (var t in eTasks)
                await t();
        }
        public event Func<Task> AlarmReceived;
    }

<pre>
class Consumer
{
    public Consumer(string name = null)
    {
        Name = name;
    }
    public string Name { get; set; }

    public AlarmSource Source
    {
        get { return source; }
        set
        {
            Func<Task> handler = () => Task.Run(() => Console.WriteLine(Name));
            if (source != null)
                source.AlarmReceived -= handler;
            source = value;
            if (source != null)
                source.AlarmReceived += handler;
        }
    }
    AlarmSource source;
}

class Program
{
    static void Main(string[] args)
    {
        DoAsyncStuff().Wait();
        Console.ReadLine();
    }
    static async Task DoAsyncStuff()
    {
        var c1 = new Consumer("A");
        var c2 = new Consumer("B");
        var src = new AlarmSource();
        c1.Source = src;
        c2.Source = src;
        await src.OnAlarm();
        c2.Source = null;
        await src.OnAlarm();
    }
}</pre>

public AlarmSource Source
{
    get { return source; }
    set
    {
        Func<Task> handler = () => Task.Run(() => Console.WriteLine(Name));
        if (source != null)
            source.AlarmReceived -= handler;
        source = value;
        if (source != null)
            source.AlarmReceived += handler;
    }
}
AlarmSource source;

public AlarmSource Source
{
    get { return source; }
    set
    {
        if (source != null)
            source.AlarmReceived -= () => Task.Run(() => Console.WriteLine(Name));
        source = value;
        if (source != null)
            source.AlarmReceived += () => Task.Run(() => Console.WriteLine(Name));
    }
}
AlarmSource source;

How to: Subscribe to and Unsubscribe from Events (C# Programming Guide)[^]

It is important to notice that you cannot easily unsubscribe from an event if you used an anonymous function to subscribe to it. To unsubscribe in this scenario, it is necessary to go back to the code where you subscribe to the event, store the anonymous method in a delegate variable, and then add the delegate to the event. In general, we recommend that you do not use anonymous functions to subscribe to events if you will have to unsubscribe from the event at some later point in your code.

Func<Task> handler = HiddenAnonymousMethod1;
if (source != null)
    source.AlarmReceived -= handler;
source = value;
if (source != null)
    source.AlarmReceived += handler;

if (source != null)
    source.AlarmReceived -= HiddenAnonymousMethod1;
source = value;
if (source != null)
    source.AlarmReceived += HiddenAnonymousMethod2;

private static readonly Task CompletedTask = Task.FromResult(true);

private IEnumerable<Func<Task>> GetAlarmInvocationList()
{
    lock (this)
    {
        Func<Task> handler = eAlarmReceived;
        if (handler == null) return null;
        return handler.GetInvocationList().Cast<Func<Task>>().ToList();
    }
}

internal Task OnAlarm()
{
    var eTasks = GetAlarmInvocationList();
    if (eTasks == null) return CompletedTask;
    
    var tasks = eTasks.Select(fn => fn());
    return Task.WhenAll(tasks);
}

var eTasks = handler?.GetInvocationList()?.Cast<Func<Task>>()?.ToList();
if (eTask == null)
  return;
foreach (var t in eTask)
  await t();

Quote:

- The term 'Import-Module' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. - System.Management.Automation - at System.Management.Automation.PowerShell.CoreInvoke[TOutput](IEnumerable input, PSDataCollection`1 output, PSInvocationSettings settings) at System.Management.Automation.PowerShell.Invoke(IEnumerable input, PSInvocationSettings settings) at System.Management.Automation.PowerShell.Invoke(IEnumerable input) at System.Management.Automation.RemotePipeline.Invoke(IEnumerable input) at System.Management.Automation.Runspaces.Pipeline.Invoke() at exchangePictureUpdater.exchangePictureUpdater.btnAddReplace_Click(Object sender, EventArgs e) - Void CoreInvoke[TOutput](System.Collections.IEnumerable, System.Management.Automation.PSDataCollection`1[TOutput], System.Management.Automation.PSInvocationSettings) |

Command command1 = new Command("set-adserversettings");
CommandParameter parameter1 = new CommandParameter("viewentireforest", true);
command1.Parameters.Add(parameter1);

Command command2 = new Command("set-userphoto");
CommandParameter parameter2a = new CommandParameter("identity", tbxName.Text);
CommandParameter parameter2b = new CommandParameter("picturedata", displayedImage);
CommandParameter parameter2c = new CommandParameter("domaincontroller", "adfadfadf.com");
CommandParameter parameter2d = new CommandParameter("confirm", false);
command2.Parameters.Add(parameter2a);
command2.Parameters.Add(parameter2b);
command2.Parameters.Add(parameter2c);
command2.Parameters.Add(parameter2d);

Pipeline pipeline = runspacee.CreatePipeline();

pipeline.Commands.Add(command1);
pipeline.Commands.Add(command2);

string scriptText = @"$pw = convertto-securestring -AsPlainText -Force -String '<password>'; $cred = new-object -typename System.Management.Automation.PSCredential -argumentlist '<domain>\<username>', $pw;  $session = new-pssession -ConfigurationName Microsoft.Exchange -ConnectionUri '<server url>/powershell' -credential $cred; import-pssession $session; Set-ExecutionPolicy bypass -confirm:$false -force; $pic = ([System.IO.File]::ReadAllBytes('" + <picture file name> + "')); set-userphoto -identity <username> -picturedata $pic -domaincontroller '<dc fqdn>' -confirm:$false;";

               
                runExchangeShellScript(scriptText);

private string runExchangeShellScript(string scriptText)
        {
            
            Runspace runspace = RunspaceFactory.CreateRunspace();

            // open it
            runspace.Open();

            // create a pipeline and feed it the script text
            Pipeline pipeline = runspace.CreatePipeline();
            pipeline.Commands.AddScript(scriptText);
            RunspaceInvoke runSpaceInvoker = new RunspaceInvoke(runspace);
            runSpaceInvoker.Invoke("Set-ExecutionPolicy Unrestricted");

            // add an extra command to transform the script output objects into nicely formatted strings
            // remove this line to get the actual objects that the script returns. For example, the script
            // "Get-Process" returns a collection of System.Diagnostics.Process instances.
            //pipeline.Commands.Add("Out-String");

            // execute the script
            Collection<PSObject> results = null;
            try
            {
                results = pipeline.Invoke();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.InnerException + " - " + ex.Message + " - " + ex.Source + " - " + ex.StackTrace + " - " + ex.TargetSite + " - " + ex.Data);
                return "";
            }


            // close the runspace
            runspace.Close();

            // convert the script result into a single string
            StringBuilder stringBuilder = new StringBuilder();
            foreach (PSObject obj in results)
            {
                stringBuilder.AppendLine(obj.ToString());
            }

            // return the results of the script that has
            // now been converted to text
            return stringBuilder.ToString();
        }