/// <summary>
/// Creates an enumerable list of instances of the specified type create from
/// a data reader.
/// </summary>
/// <typeparam name="T">
/// The data object type. This should be a class with properties matching the reader
/// value.
/// </typeparam>
/// <param name="reader">An open reader ready to be read to a list.</param>
/// <returns>An enumerable list of instances of type 'T' created from the data reader.</returns>
public static IEnumerable <T> ReadData <T>(this DbDataReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("reader");
}
var result = new List <T>();
if (EntityMapping.IsSimpleType <T>())
{
while (reader.Read())
{
result.Add(EntityMapping.ReadHelper.Get <T>(reader, 0));
}
}
else
{
var map = EntityMapping.MapDbReaderColumns(reader);
var readEntity = EntityMapping.GetEntityFunc <T>();
while (reader.Read())
{
result.Add(readEntity(reader, map));
}
}
return(result);
}
public ResultStreamEnumerator(IContext context, SqlCommandManager manager)
{
_isSimpleType = EntityMapping.IsSimpleType <T>();
_readEntity = _isSimpleType ? GetSimple : EntityMapping.GetEntityFunc <T>();
_connection = AsyncHelper.RunSync(() => manager.CreateConnectionAsync());
_command = _connection.CreateCommand();
_command.Connection = _connection;
_command.CommandText = context.CommandText;
manager.AddParametersToCommand(_command, context);
_connection.Open();
_reader = _command.ExecuteReader();
_map = _isSimpleType ? null : EntityMapping.MapDbReaderColumns(_reader);
}
/// <summary>
/// Creates a dictionary from a single row of a data reader, setting the dictionary key to the column names
/// and the value to the values from the row.
/// </summary>
/// <param name="reader">An open reader with at least one row result (subsequent rows are ignored.)</param>
/// <param name="columns">The columns to read. If this value is null, all columns will be returned.</param>
/// <returns>A dictionary created from the first row of the data reader.</returns>
/// <remarks>Keep in mind that result may contain DbNull type values.</remarks>
public static IDictionary <string, object> CreateColumnKeyedDictionary(this DbDataReader reader, IEnumerable <string> columns)
{
if (reader.Read())
{
if (columns?.Any() != true)
{
var map = EntityMapping.MapDbReaderColumns(reader);
return(map.ToDictionary(k => k.Key, v => reader[v.Value]));
}
else
{
return(columns.ToDictionary(k => k, v => reader[v]));
}
}
return(null);
}
/// <summary>Processes the command and generates a custom result.</summary>
/// <param name="reader">An open data reader queued to the appropriate result set.</param>
/// <returns>The result of the processor for this query.</returns>
public object Process(DbDataReader reader)
{
var map = EntityMapping.MapDbReaderColumns(reader);
return(_valueProvider(reader, map));
}
