Dapper and anonymous Types

Question

Is it possible to use anonymous types with Dapper?

I can see how you can use dynamic i.e.

connection.Query(blah, blah, blah) 
         


        

Answer 1

Just a small improvement of Guillaume86's great solution:

public static IEnumerable<T> Query<T>(this IDbConnection connection, Func<T> typeBuilder,
    string sql, dynamic param = null, IDbTransaction transaction = null,
    bool buffered = true, int? commandTimeout = null, CommandType? commandType = null)
{
    return SqlMapper.Query<T>(connection, sql, param, transaction, buffered,
        commandTimeout, commandType);
}

Answer 2

Is it possible to use anonymous types with Dapper?

Sure see the non-generic Query override, it return a dynamic IDictionary<string, object> this object is an expando that can either be cast or accessed with dot notation.

Eg:

var v = connection.Query("select 1 as a, 2 as b").First(); 
Console.Write("{0} {1}",v.a, v.b) // prints: 1 2

is it then possible to do a .Select

Sure, you get an IEnumerable<dynamic> ... you can run anything you want on that.

Answer 3

Here's another solution to use anonymous types with dapper:

public static class DapperExtensions
{
    public static IEnumerable<T> Query<T>(this IDbConnection connection, Func<T> typeBuilder, string sql)
    {
        return connection.Query<T>(sql);
    }
}

and use it like this:

var data = connection.Query(() => new 
{
    ContactId = default(int),
    Name = default(string),
}, "SELECT ContactId, Name FROM Contact");