public override void Execute()
{
Console.WriteLine("dynamic item = new ExpandoObject();");
dynamic item = new ExpandoObject();
// we can add properties ad-hoc
Console.WriteLine("item.Name = \"Billy\";");
item.Name = "Billy";
Console.WriteLine("item.DoB = new DateTime(1999, 02, 22);");
item.DoB = new DateTime(1999, 02, 22);
// and add methods
item.DoBIncrement = (Action)(() => { item.DoB = item.DoB.AddYears(+1); });
// and call them
item.DoBIncrement();
Console.WriteLine("item.DoB.ToString()");
Console.WriteLine(item.DoB.ToString());
Console.WriteLine("item.Name");
Console.WriteLine(item.Name);
// we can also change the properties radically
Console.WriteLine("item.Name = 1.2;");
item.Name = 1.2;
Console.WriteLine("item.Name.GetType().ToString()");
Console.WriteLine(item.Name.GetType().ToString());
// we can pass it as a parameter (as long as the dynamic keyword is used)
ShowName(item);
// we can also add events (but we must first initialise them with null!)
item.SomethingHappened = null;
item.SomethingHappened += new EventHandler<NameEventArgs>(NowWeNowThatSomethingHappened);
// also implement the handler in a fairly normal way
item.OnSomethingHappened = (Action)(() =>
{
if (item.SomethingHappened != null)
{
item.SomethingHappened(item, new NameEventArgs(item.Name));
}
});
// and hook up to them externally...
item.Name = "Billy Bunter";
item.OnSomethingHappened();
// we can also list the properties
Console.WriteLine("Properties, Methods, etc... are stored as a IDictionary<String,Object> :");
foreach (var property in (IDictionary<String, Object>)item)
{
Console.WriteLine("\tkey: " + property.Key + ", value: " + property.Value);
}
// throws a LANGUAGE-SPECIFIC error when retrieving a non-existant property!
// ?? presumably a VB.NET authored DLL would throw a _different_ error? ??
try
{
Console.WriteLine("item.Salary");
Console.WriteLine(item.Salary);
}
catch(Microsoft.CSharp.RuntimeBinder.RuntimeBinderException e)
{
Console.WriteLine(e.Message);
}
Console.ForegroundColor = ConsoleColor.Cyan;
// VB.NET has had late-binding dynamic-like behaviour - but the behaviours/exceptions are different
// keyword "dynamic" is a C# ONLY feature
Console.WriteLine("(* VB.NET *)");
Console.WriteLine("ExpandoTest test = new ExpandoTest();");
ExpandoTest test = new ExpandoTest();
try
{
Console.WriteLine("test.NonExistantProperty();");
Console.WriteLine(test.NonExistantProperty());
}
catch (MissingMemberException e)
{
Console.WriteLine(e.Message);
}
Console.ResetColor();
}