Dynamic objects were first added in C# 4 and are useful in many dynamic scenarios when dealing with JSON objects. They can also be useful when you don't want to write an entire C# class just to match your database table structure.
Let's consider the following example, which returns all the authors based on the ids passed as a parameter.
private static void GetAuthors(params int[] ids)
{
using (IDbConnection db = new SqlConnection(ConnectionString))
{
List<Author> authors =
db.Query<Author>("SELECT * FROM Authors WHERE Id IN @Ids", new { Ids = ids })
.ToList();
foreach (var author in authors)
{
Console.WriteLine(author.FirstName + " " + author.LastName);
}
}
}
Let's implement the same functionality using dynamic objects instead of using the concrete Author class.
private static void GetDynamicAuthors(params int[] ids)
{
using (IDbConnection db = new SqlConnection(ConnectionString))
{
List<dynamic> authors =
db.Query("SELECT * FROM Authors WHERE Id IN @Ids", new { Ids = ids })
.ToList();
foreach (var author in authors)
{
Console.WriteLine(author.FirstName + " " + author.LastName);
}
}
}
You can see that we specified dynamic instead of Author as the generic type, and also, there is no need, to specify the generic type of the Query method.
You will notice when you started typing author., you won't get IntelliSense because it's a dynamic object. Let's call this new method and execute the application, and you will see that everything is still working the same.