How to obtain List from executing stored procedure that needs parameters?

Can someone tell me the syntax for doing this? I can't find anything on https://github.com/StackExchange/dapper-dot-net

Here's what I have so far:

using (con = new SqlConnection(connectionString))
{
    DynamicParameters param = new DynamicParameters();
    Debug.WriteLine(Int32.Parse(ConfigurationManager.AppSettings["max-files-limit"]));
    param.Add("@NumOfFiles", Int32.Parse(ConfigurationManager.AppSettings["max-files-limit"]));
    con.Open();
    IList<AsyncFileProcessingQueue> fileList = SqlMapper.Query<AsyncFileProcessingQueue>(con, "GetMostRecentFileStatus", param).ToList();
    return fileList.ToList();
}

I'm getting this error,

Procedure or function 'GetMostRecentFileStatus' expects parameter '@NumOfFiles', which was not supplied.

GetMostRecentFileStatus is a stored Procedure. I don't know if this might be the issue. but I was thinking that maybe it doesn't know I'm using a stored procedure?

I saw an example like this

var p = new DynamicParameters();
p.Add("@a", 11);
p.Add("@b", dbType: DbType.Int32, direction: ParameterDirection.Output);
p.Add("@c", dbType: DbType.Int32, direction: ParameterDirection.ReturnValue);

cnn.Execute("spMagicProc", p, commandType: CommandType.StoredProcedure); 

int b = p.Get<int>("@b");
int c = p.Get<int>("@c"); 

But how can I get a List instead of outputs?

The stored procedure looks like this

CREATE PROCEDURE GetMostRecentFileStatus
(
    @NumOfFiles INT
)
AS
BEGIN
SELECT TOP (@NumOfFiles) Filename, Status
FROM AsyncFileProcessingQueue
ORDER BY UpdatedDate DESC
END