/// <summary>
/// Reads the current column, returns its value according to <paramref name="type"/> and
/// moves ahead to the next column.
/// If the column is null an exception is thrown.
/// </summary>
/// <param name="type">
/// In some cases <typeparamref name="T"/> isn't enough to infer the data type coming in from the
/// database. This parameter and be used to unambiguously specify the type. An example is the JSONB
/// type, for which <typeparamref name="T"/> will be a simple string but for which
/// <paramref name="type"/> must be specified as <see cref="NpgsqlDbType.Jsonb"/>.
/// </param>
/// <typeparam name="T">The .NET type of the column to be read.</typeparam>
/// <returns>The value of the column</returns>
public T Read <T>(NpgsqlDbType type)
{
CheckDisposed();
if (_column == -1 || _column == NumColumns)
{
throw new InvalidOperationException("Not reading a row");
}
var handler = _typeHandlerCache[_column];
if (handler == null)
{
handler = _typeHandlerCache[_column] = _typeMapper.GetByNpgsqlDbType(type);
}
return(DoRead <T>(handler));
}
ValueTask <T> Read <T>(NpgsqlDbType type, bool async, CancellationToken cancellationToken = default)
{
CheckDisposed();
if (_column == -1 || _column == NumColumns)
{
throw new InvalidOperationException("Not reading a row");
}
var handler = _typeHandlerCache[_column];
if (handler == null)
{
handler = _typeHandlerCache[_column] = _typeMapper.GetByNpgsqlDbType(type);
}
return(DoRead <T>(handler, async, cancellationToken));
}