This document discusses using dynamic typing in C# 4.0 and later versions. It provides examples of using dynamic to call methods on objects without explicit casting, to access custom document properties in Microsoft Office applications, and to call functions defined in IronRuby or IronPython scripts from C# code.

1. C# 4.0
dynamic
or:
How I Learned to Stop Worrying and
Love dynamic

3. “C# is still a statically typed language everywhere that
you are not using dynamic” – John Skeet
"Oh, well it's statically-typed as a dynamic type.“ – Scott
Hanselman blog
“C# is evolving nicely by introducing dynamic typing
through a static type called dynamic” – Nikhil Kothari

5. Office Interop
object oDocCustomProps = doc.CustomDocumentProperties;
Type typeDocCustomProps = oDocCustomProps.GetType();
typeDocCustomProps.InvokeMember(
"Item",
BindingFlags.Default |
BindingFlags.SetProperty,
null, oDocCustomProps,
new object[] {propertyName, propertyValue});
VS
aDoc.CustomDocumentProperties["CustomProperty1"] = "Alt.NET";

6. Calling Iron* from C#
ScriptEngine engine = Ruby.CreateEngine();
ScriptScope scope = engine.CreateScope();
engine.ExecuteFile("tax.rb", scope);
var CalculateTax =
scope.GetVariable<Func<TaxableItem[], decimal>>("calculate_tax");
var items = new TaxableItem[] {
new TaxableItem("Cola", 2.5),
new TaxableItem("Donut",1.5)
};
var tax = CalculateTax(items);
Console.WriteLine("Tax: {0}", tax);
Console.ReadLine();

7. Calling Iron* from C#
class Item def calculate_tax(items)
def initialize(name, price) total = 0.0
@name = name
@price = price items.each do |item|
end total += item.price * 0.1
end
def name
@name return total
end end
def price
@price
end
end