C# How to check if we've 'had' values from a method without having to re-call the method [closed]

Question

Currently I'm saving the values, gotten from a method, to a variable and using them later on.

This is the example code of how I do it:

var events = class.GetEvents();

if(events.Length > 0)
{
     foreach(var event in events)
     {
        // do something
     }
}       
else
{
     // No events
     Console.Log("No Events");
}

But actually, What I'd like to achieve is something more like this:

foreach(var event in class.GetEvents()) // <-- If none, I'd like to know.
{
      // do something
} 

However, I still need to log that there weren't any results. I'd have to do a check, and re-call the method to see if there are any results.. OR i++ in my loop, and if that's a 0 => log.

Is there a simpler way to do this?

Answer 1

I don't understand why you don't want to use a variable. However, one way is to provide an extension method for this:

public static void ForEachDo<T>(this IEnumerable<T> seq, Action<T> doWithEveryItem, Action doIfEmpty = null)
{
    bool isEmpty = true;
    foreach (T item in seq)
    {
        isEmpty = false;
        doWithEveryItem(item);
    }
    if (isEmpty && doIfEmpty != null)
        doIfEmpty();
}

Now you can use it with everything that implements IEnumerable<T> like a string:

"".ForEachDo(Console.WriteLine, () => Console.WriteLine("No Events")); // prints "No Events"

Answer 2

You can use Debug.WriteIf method for this.

public void Method() 
{
    var events = class.GetEvents();
    Debug.WriteIf(events.Length > 0, "No Events");

    foreach(var event in events)
    {
        // do something
    } 
}

You can check it's documentation here.

Of course this will be executed only in Debug configuration and will output to Output window, but you can easily borrow the idea for your logger and do the same logic.