Multitasking, how to run more than one object in foreach in the same time?

Question

I have more than one reader and I want to run all at the same time. I get reader IP and data from the same query in database use this query:

var deviceSetupsInfo = entities.LaneDeviceSetups
                  .Where(e => e.DeviceTypeId == 1)
                  .Select(e => new {
                     e.Ip,
                     e.LaneId,
                     e.TableName,
                     e.DeviceTypeId
                 }).ToList();

for (int i = 0; i < deviceSetupsInfo.Count; i++) {     
         Task.Run(() => new RFIDReader(
                            deviceSetupsInfo[i].Ip, 
                            deviceSetupsInfo[i].LaneId.Value,
                            deviceSetupsInfo[i].TableName, 
                            deviceSetupsInfo[i].DeviceTypeId.Value
                        )
         );
}

I want all return readers in [i] in loop run in the same time.

why not `Forech(var item in deviceSetupsInfo) { }`, you need to include what RFIDReader actaully is, more code needed — Seabizkit, Feb 01 '21 at 09:54
`Parallel.ForEach`. Or `AsParallel().Select()`. I mean it is likely going to be massively slower... — mjwills, Feb 01 '21 at 10:48
Your code may be affected by this problem: [Captured variable in a loop in C#](https://stackoverflow.com/questions/271440/captured-variable-in-a-loop-in-c-sharp). — Theodor Zoulias, Feb 01 '21 at 14:36

SIbghat · Answer 1 · 2021-02-03T05:37:30.773

0

parallel.foreach is the solution, lock is optional to avoid the edge cases

 object locker = new object();
    Parallel.ForEach(deviceSetupsInfo, (item) =>
                 {
                       //do stuff
                     
                 });

edited Feb 03 '21 at 05:37

answered Feb 02 '21 at 11:45

SIbghat

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The `lock` statement creates synchronized blocks of code, where only one thread can enter at a time. As such, it defeats the purpose of `Parallel.ForEach` IMHO. – Theodor Zoulias Feb 02 '21 at 15:00
If parallell processes are sharing same object due to any reason, it would break without a lock. Lock necer makes in synchrounous. It holds resources just for a fraction – SIbghat Feb 03 '21 at 05:36
thank you i use it ` new Thread(() => Parallel.ForEach(deviceSetupsInfo, device => )).Start();` – Ramy Atef Feb 03 '21 at 09:10

Multitasking, how to run more than one object in foreach in the same time?

1 Answers1