expandoobject

I am trying to learn all the new goodies that come with C# 4.0. I am failing to understand the differences between the DynamicObject and ExpandoObject types. It seems like DynamicObject is used e.g. when you want to access variables from Python scripts and ExpandoObject when talking with COM/Office objects. Am I right? What is the difference in their use? Expando is a dynamic type to which members can be added (or removed) at runtime. dynamic is designed to allow .NET to interoperate with types when interfacing with dynamic typing languages such as Python and JavaScript. So, if you need to

I am attempting to display the results of a query in a WPF datagrid. The ItemsSource type I am binding to is IEnumerable<dynamic> . As the fields returned are not determined until runtime I don't know the type of the data until the query is evaluated. Each "row" is returned as an ExpandoObject with dynamic properties representing the fields. It was my hope that AutoGenerateColumns (like below) would be able to generate columns from an ExpandoObject like it does with a static type but it does not appear to. <DataGrid AutoGenerateColumns="True" ItemsSource="{Binding Results}"/> Is there anyway

What are the differences between System.Dynamic.ExpandoObject , System.Dynamic.DynamicObject and dynamic ? In which situations do you use these types? SLaks The dynamic keyword is used to declare variables that should be late-bound. If you want to use late binding, for any real or imagined type, you use the dynamic keyword and the compiler does the rest. When you use the dynamic keyword to interact with a normal instance, the DLR performs late-bound calls to the instance's normal methods. The IDynamicMetaObjectProvider interface allows a class to take control of its late-bound behavior. When

In javascript you can detect if a property is defined by using the undefined keyword: if( typeof data.myProperty == "undefined" ) ... How would you do this in C# using the dynamic keyword with an ExpandoObject and without throwing an exception? According to MSDN the declaration shows it is implementing IDictionary: public sealed class ExpandoObject : IDynamicMetaObjectProvider, IDictionary<string, Object>, ICollection<KeyValuePair<string, Object>>, IEnumerable<KeyValuePair<string, Object>>, IEnumerable, INotifyPropertyChanged You can use this to see if a member is defined: var expandoObject =

I really like the ExpandoObject while compiling a server-side dynamic object at runtime, but I am having trouble flattening this thing out during JSON serialization. First, I instantiate the object: dynamic expando = new ExpandoObject(); var d = expando as IDictionary<string, object>; expando.Add("SomeProp", SomeValueOrClass); So far so good. In my MVC controller, I want to then send this down as a JsonResult, so I do this: return new JsonResult(expando); This serializes the JSON into the below, to be consumed by the browser: [{"Key":"SomeProp", "Value": SomeValueOrClass}] BUT, what I'd really