Using the iterator variable of foreach loop in a lambda expression – why fails?

Welcome to the world of closures and captured variables 🙂

Eric Lippert has an in-depth explanation of this behaviour:

• Closing over the loop variable considered harmful
• Closing over the loop variable, part two

basically, it’s the loop variable that is captured, not it’s value.
To get what you think you should get, do this:

foreach (var type in types)
{
   var newType = type;
   var sayHello = 
            new PrintHelloType(greeting => SayGreetingToType(newType, greeting));
   helloMethods.Add(sayHello);
}