/// <summary>
/// Create and prepare a SQLiteCommand, and call ExecuteReader with the appropriate CommandBehavior.
/// </summary>
/// <remarks>
/// If we created and opened the connection, we want the connection to be closed when the DataReader is closed.
///
/// If the caller provided the connection, we want to leave it to them to manage.
/// </remarks>
/// <param name="connection">A valid SQLiteConnection, on which to execute this command</param>
/// <param name="transaction">A valid SQLiteTransaction, or 'null'</param>
/// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">The stored procedure name or T-SQL command</param>
/// <param name="commandParameters">An array of SQLiteParameters to be associated with the command or 'null' if no parameters are required</param>
/// <param name="connectionOwnership">Indicates whether the connection parameter was provided by the caller, or created by SqlHelper</param>
/// <returns>SQLiteDataReader containing the results of the command</returns>
public static SQLiteDataReader ExecuteReader(SQLiteConnection connection, SQLiteTransaction transaction,
CommandType commandType, string commandText,
SQLiteParameter[] commandParameters,
SQLiteConnectionOwnership connectionOwnership)
{
if (connection == null) throw new ArgumentNullException("connection");
bool mustCloseConnection = false;
SQLiteCommand cmd = new SQLiteCommand();
try
{
PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters,
out mustCloseConnection);
SQLiteDataReader dataReader = connectionOwnership == SQLiteConnectionOwnership.External ? cmd.ExecuteReader() : cmd.ExecuteReader(CommandBehavior.CloseConnection);
// Detach the SQLiteParameters from the command object, so they can be used again.
// HACK: There is a problem here, the output parameter values are fletched
// when the reader is closed, so if the parameters are detached from the command
// then the SqlReader can´t set its values.
// When this happen, the parameters can´t be used again in other command.
bool canClear = true;
foreach (SQLiteParameter commandParameter in cmd.Parameters)
{
if (commandParameter.Direction != ParameterDirection.Input)
canClear = false;
}
if (canClear)
{
cmd.Parameters.Clear();
}
return dataReader;
}
catch
{
if (mustCloseConnection)
connection.Close();
throw;
}
}
private static SQLiteDataReader ExecuteReader(SQLiteConnection connection, SQLiteTransaction transaction, CommandType commandType, string commandText, SQLiteParameter[] commandParameters, SQLiteConnectionOwnership connectionOwnership)
{
if (connection == null)
{
throw new ArgumentNullException("connection");
}
bool mustCloseConnection = false;
SQLiteCommand cmd = new SQLiteCommand();
try
{
PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
SQLiteDataReader dataReader;
//Call ExecuteReader with the appropriate CommandBehavior
if (connectionOwnership == SQLiteConnectionOwnership.External)
{
dataReader = cmd.ExecuteReader();
}
else
{
dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
}
// 清除参数,以便再次使用..
// HACK: There is a problem here, the output parameter values are fletched
// when the reader is closed, so if the parameters are detached from the command
// then the SqlReader can set its values.
// When this happen, the parameters can be used again in other command.
bool canClear = true;
foreach (SQLiteParameter commandParameter in cmd.Parameters)
{
if (commandParameter.Direction != ParameterDirection.Input)
{
canClear = false;
}
}
if (canClear)
{
cmd.Parameters.Clear();
}
return(dataReader);
}
catch
{
if (mustCloseConnection)
{
connection.Close();
}
throw;
}
}