The Dynamic Duo: ExpandoObject and DynamicObject – Part 1

After shortly explaining the new dynamic keyword in my previous post we will look at the ExpandoObject class which offers a dynamic structure. What does this mean exactly?! Well you can get and set Properties which are not existent at design-time and also define and call methods on the ExpandoObject like this:

dynamic expando = new ExpandoObject()
expando.MyProperty1 = "This is a string prop";
expando.MyProperty2 = 12;
expando.MyFunction = (Func<String>)(() =>
                     {
                         return String.Format("{0}", expando.MyProperty1);
                     });

Furthermore it supports change notifications via INotifyPropertyChanged out of the box as well as Events (sort of).

So do you need this? As always: it depends. On what? Well if you are looking for a dynamic structure you could also use a combination of Dictionary-Voodoo like this:

Dictionary<String, object> paulie = new Dictionary<string, object>();
paulie["FirstName"] = "Paulie";
paulie["LastName"] = "Baker";

Dictionary<String, object> people = new Dictionary<string, object>();
people["Paulie"] = paulie;

Console.WriteLine(((Dictionary<string, object>)people["Paulie"])["FirstName"]);

Besides the much cleaner coding, there’s again INotifyPropertyChanged, Methods and Events on the Expando side. Also it implements IDynamicMetaObjectProvider which allows for interop with DLR objects.

As always the source can be downloaded here: http://dl.dropbox.com/u/13456770/IDevign/IDevign.Expando.zip

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