/// <summary>
/// Creates a new instance of the <see cref="SqlFileStreamReadStream" /> class with the specified connection, table,
/// data field, and where criteria action.
/// </summary>
/// <param name="connection">The <see cref="IDbConnection" /> to use.</param>
/// <param name="table">The table in which the data is stored.</param>
/// <param name="dataField">The field in which the data is stored</param>
/// <param name="criteriaAction">The <see cref="BuildWhereCriteriaAction"/> to use to generate criteria that identifies the record.</param>
public SqlFileStreamReadStream(IDbConnection connection, string table, string dataField, BuildWhereCriteriaAction criteriaAction)
: base(connection, OpenConnectionAndBeginTransaction(connection))
{
// TODO: add buffering
try
{
using (SqlCommand cmd = ((SqlConnection)Connection).CreateCommand())
{
cmd.CommandText = "SELECT " + dataField + ".PathName(), GET_FILESTREAM_TRANSACTION_CONTEXT() FROM " + table + " WHERE " + criteriaAction(cmd);
cmd.Transaction = (SqlTransaction)Transaction;
using (SqlDataReader rd = cmd.ExecuteReader(CommandBehavior.SingleRow))
{
rd.Read();
string path = rd.GetString(0);
byte[] context = (byte[])rd.GetValue(1);
// todo: fileoptions, allocationsize
_innerStream = new SqlFileStream(path, context, FileAccess.Read);
}
}
}
catch
{
if (_innerStream != null)
_innerStream.Dispose();
base.Close();
// TODO: cleanup
throw;
}
}
