this.Loaded += (s, e) => this.loaded = true; ???

Question

Hello,

would someone please write this code:

this.Loaded += (s, e) => this.loaded = true;

into several code lines so I can retrace the meaning?

In my code sample there is no s or e ?

Answer 1

It's a shorthand for an event handler. s is what you normally see as object sender and e is some type of EventArgs. Basically it could be written like this:

public void MyHandler(object sender, EventArgs e)
{
   this.loaded = true;
}

and the calling code would be something like:

this.Loaded += MyHandler;

Answer 2

This may make it slightly clearer, just by renaming:

this.Loaded += (sender, args) => this.loaded = true;

Or by giving them types:

this.Loaded += (object sender, EventArgs args) => this.loaded = true;

They're the parameters for the delegate. Here's the equivalent in C# 2:

this.Loaded += delegate (object sender, EventArgs args) { this.loaded = true; };

Does that help?

Here's the equivalent in C# 1 (fortunately there are no captured variables, which makes life a bit easier...)

this.Loaded += new EventHandler(SetLoadedToTrue);

...

private void SetLoadedToTrue(object sender, EventArgs args)
{
    this.loaded = true;
}

(That's all assuming the Loaded event is of type EventHandler; if it's not, the signature would be different in the obvious way.)