您可以像这样实现一个自定义的EventHandler。

public class StatusChangedEventArgs : EventArgs
{
    public Status OldValue { get; }
    public Status NewValue { get; }

    public StatusChangedEventArgs(Status oldValue, Status newValue)
    {
        OldValue = oldValue;
        NewValue = newValue;
    }
}

public sealed class MyCustomTextBlock : Control
{
    public enum Status
    { 
        Waiting,
        Busy,
    }
    
    private Status currentStatus;
    public Status CurrentStatus
    {
        get { return currentStatus; }
    }

    public MyCustomTextBlock()
    {
        this.DefaultStyleKey = typeof(MyCustomTextBlock);
        currentStatus = Status.Waiting;
    }

    public event EventHandler<StatusChangedEventArgs>? StatusChanged;

    protected void OnStatusChanged(Status oldValue, Status newValue)
    {
        StatusChanged?.Invoke(this, new StatusChangedEventArgs(oldValue, newValue));
    }
}