public IEnumerable <CardModel> SelectRandomCardModels(int count, params string[] conditions)
{
if (count < 0)
{
throw new ArgumentOutOfRangeException("count");
}
if (count == 0)
{
return(Enumerable.Empty <CardModel>());
}
DataTable table = SelectCards(conditions);
IEnumerable <DataRow> candidates;
if (table.Rows.Count <= count)
{
candidates = table.Rows.Cast <DataRow>();
}
else
{
var rnd = new Random();
IEnumerable <int> indexes = from i in Enumerable.Range(0, table.Rows.Count)
let pair = new KeyValuePair <int, double>(i, rnd.NextDouble())
orderby pair.Value
select pair.Key;
candidates = from i in indexes.Take(count)
select table.Rows[i];
}
return(candidates.Select(r => CardModel.FromDataRow(this, r)));
}
public IEnumerable <CardModel> SelectCardModels(params string[] conditions)
{
return(from DataRow row in SelectCards(conditions).Rows
select CardModel.FromDataRow(this, row));
}
