FastExpando and Mutations

The FastExpando supports two methods to help your code look nicer - Mutate and Transform. Both of them accept a map (a dictionary of string to string), and convert the field names into new field names. This is handy when you have icky column names coming back from the database, and you want to make them pretty before returning them to your object code.

• expando.Mutate(map) - modifies the current expando in-place
• dynamic newexpando = expando.Transform(map) - transforms an expando into a new expando

Usually you will have the mapping as a static dictionary that is reused across calls.

In all cases, unmapped properties are retained as-is.

NOTE: if you map two source properties to the same target value, the behavior is undefined.

FastExpando.Mutate

var mapping = new Dictionary<string, string>() { { "Name", "TheName" } };

dynamic beer = Database.Connection().QuerySql("SELECT * FROM Beer WHERE Name = @Name", new { Name = "IPA" }).First();
beer.Mutate(mapping);
Console.WriteLine(beer.TheName);

FastExpando.Transform

dynamic beer = Database.Connection().QuerySql("SELECT * FROM Beer WHERE Name = @Name", new { Name = "IPA" }).First().Transform(mapping);
Console.WriteLine(beer.TheName);

Transforming a List

IEnumerable also supports transforming the objects while enumerating:

foreach (dynamic beer in Database.Connection().QuerySql("SELECT * FROM Beer WHERE Name = @Name", new { Name = "IPA" }).Transform(mapping))
	Console.WriteLine(beer.TheName);