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The Lambda function handler is the method in your function code that processes events. When your function is invoked, Lambda runs the handler method. When the handler exits or returns a response, it becomes available to handle another event.
A lambda expression lets you create an anonymous class that implements a specific type of interface - a functional interface - which has one and only one abstract method. The EventHandler interface used to handle JavaFX events has just one abstract method, handle.
The term 'Lambda expression' has derived its name from 'lambda' calculus which in turn is a mathematical notation applied for defining functions. Lambda expressions as a LINQ equation's executable part translate logic in a way at run time so it can pass on to the data source conveniently.
In particular, a lambda function has the following characteristics: It can only contain expressions and can't include statements in its body. It is written as a single line of execution.
There are no performance implications since the compiler will translate your lambda expression into an equivalent delegate. Lambda expressions are nothing more than a language feature that the compiler translates into the exact same code that you are used to working with.
The compiler will convert the code you have to something like this:
public partial class MyPage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//snip
MyButton.Click += new EventHandler(delegate (Object o, EventArgs a)
{
//snip
});
}
}
Performance-wise it's the same as a named method. The big problem is when you do the following:
MyButton.Click -= (o, i) =>
{
//snip
}
It will probably try to remove a different lambda, leaving the original one there. So the lesson is that it's fine unless you also want to be able to remove the handler.
EventHandler handler = (s, e) => MessageBox.Show("Woho");
button.Click += handler;
button.Click -= handler;
No performance implications that I'm aware of or have ever run into, as far as I know its just "syntactic sugar" and compiles down to the same thing as using delegate syntax, etc.
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