C# – EventHandler type with no event args

ceventssignals

When we want to pass data to an event subscriber, we use EventArgs (or CustomEventArgs) for this.

.Net provides a build in type EventHandler that uses as a parameter an instance of EventArgs class that is build in as well.

What about cases, when I need to notify a subscriber that some action is over, for example search is over? I don't want to even use EventArgs, that won't contain anything.

Is there a build in type for signaling another class, without the need to use empty EventArgs?

Best Answer

I really would advise you to use the standard EventHandler patter here and just pass EventArgs.Empty; however, you can use Action as an event type of you really want - it is just unusual.

Related Solutions

C# – How to calculate someone’s age based on a DateTime type birthday

An easy to understand and simple solution.

// Save today's date.
var today = DateTime.Today;

// Calculate the age.
var age = today.Year - birthdate.Year;

// Go back to the year in which the person was born in case of a leap year
if (birthdate.Date > today.AddYears(-age)) age--;

However, this assumes you are looking for the western idea of the age and not using East Asian reckoning.

C# – downside to adding an anonymous empty delegate on event declaration

Instead of inducing performance overhead, why not use an extension method to alleviate both problems:

public static void Raise(this EventHandler handler, object sender, EventArgs e)
{
    if(handler != null)
    {
        handler(sender, e);
    }
}

Once defined, you never have to do another null event check again:

// Works, even for null events.
MyButtonClick.Raise(this, EventArgs.Empty);

Best Answer

Related Solutions

C# – How to calculate someone’s age based on a DateTime type birthday

C# – downside to adding an anonymous empty delegate on event declaration

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