lambda - C# => operator?

Question

I have a question about the => operator in C#.

I am looking at the Expression Blend 4 samples. There is one line in the Contact sample which includes:

//In C:Program Files (x86)Microsoft ExpressionBlend 4SamplesenContacts
//ContactsViewModelsContactsViewModel.cs: 

contactDetailWindow.Closed += (o, e) =>
{                              
   finishedCallback(contactDetailWindow.DialogResult);

   // Or, C:Program Files (x86)Microsoft ExpressionBlend 4Samplesen
   // ContactsContactsViewModelsContactsViewModel.cs
   this.EditContact(newContact, dialogResult =>
   {
        if (dialogResult.HasValue && dialogResult.Value)
        {
        this.Contacts.Add(newContact);
        }
   });
};

What is the => operator actually doing? Is it overriding something?

Answer 1

It's called the lambda operator.

 b.Click += (s, e) => Log("Sender :" + s + "EventArgs " + e);

is identical to

b.Click += b_Click;

void b_Click(object sender, EventArgs e)
{
    Log("Sender :" + sender + "EventArgs " + e);
}

or

b.Click += delegate(object sender, EventArgs e) 
           { 
               Log("Sender :" + sender + "EventArgs " + e);  
           };