Alerts - Deepchart Indicators

An indicator can warn the user with a message or a sound:

VAn.ShowMessage($"Price crossed the average ({Length})", VAn.ChartName);
VAn.PlayAlert(AlertName.SelValue);

Rules

Call them only in realtime. Every calculation method receives isRt: during the history it is false, and an alert there would fire once for every past signal.
Fire once per event. A condition which stays true is evaluated again at every update: remember that you already alerted for this bar.

bool alerted;

public override void OnOpen(bool isRt)
{
    alerted = false;
}

public override void OnEnd(bool isRt)
{
    if (isRt && !alerted && Crossed())
    {
        alerted = true;
        if (EnableAlertMessage)
            VAn.ShowMessage("Crossed", VAn.ChartName);
    }
}

Letting the user choose the sound

A parameter of type DynamicList marked as alert shows the list of the sounds configured in Deepchart:

[Category("Alert")]
[DisplayName("Alert name")]
[VolCustom(IsAlert = true)]
public DynamicList AlertName { get; set; } = new DynamicList();

AlertName.SelValue is the sound the user selected.

Messages and sounds are produced by the desktop app. When an indicator is calculated on the server, these two calls do nothing for now.

Logging

For diagnostics rather than alerts, write to the log of the app:

VAn.AddToLog("Session started", VolumetricaAPI.LogLevelEnum.Information);