private async Task UpdateItemsAsync(CancellationToken token)
{
token.ThrowIfCancellationRequested();
var newValue = await _plc.ReadItemAsync(_placeholderItem, token);
// Make a copy of all monitored plc items in a thread safe manner.
token.ThrowIfCancellationRequested();
List <IPlcItem> plcItems;
lock (_lock)
{
plcItems = new List <IPlcItem>(_plcItems);
}
// Update the value of the monitored items.
//foreach (var plcItem in plcItems)
//{
// token.ThrowIfCancellationRequested();
// plcItem.Value.TransferValuesFrom(newValue);
//}
Parallel.ForEach
(
plcItems, (plcItem) =>
{
token.ThrowIfCancellationRequested();
plcItem.Value.TransferValuesFrom(newValue);
}
);
}
/// <summary>
/// Reads the value of the <paramref name="plcItem"/> from the plc.
/// </summary>
/// <param name="plc"> The extended <see cref="IPlcItem"/> instance. </param>
/// <typeparam name="TValue"> The type of the <see cref="IPlcItem{TValue}.Value"/>. </typeparam>
/// <param name="plcItem"> The <see cref="IPlcItem{TValue}"/> to read. </param>
/// <param name="cancellationToken"> An optional <see cref="CancellationToken"/> for cancelling the read operation. </param>
/// <returns> An awaitable task containing the result as <typeparamref name="TValue"/>. </returns>
/// <exception cref="ReadPlcException"> Thrown if an exception occurred while reading. </exception>
public static async Task <TValue> ReadItemAsync <TValue>(this IPlc plc, IPlcItem <TValue> plcItem, CancellationToken cancellationToken = default)
{
await plc.ReadItemAsync(plcItem as IPlcItem, cancellationToken);
return(plcItem.Value);
}