How to execute each iteration of the loop in one thread with task?

I have a method that check some data and I would like to know how to check this data in differents threads. I am using task and async/await pattern.

private bool my myCheckMethod(List<long> paramData) { //code that check the information in the list } private void mainMethod() { //1.- get data from the data base //2.- i group the data from the database in many lists. foreach(list<List<long>> iterator in myListOfLists) { myCheckMethod(itrator); } } 

But I would like that the myCheckMethod not execute only one at time, but to use tasks to execute many at same time. I think that it would take less time.

However, I don't know well how to do that. I try something like that:

private void mainMethod() { //1.- get data from the data base //2.- i group the data from the database in many lists. string initTime = System.DateTime.String(); foreach(list<List<long>> iterator in myListOfLists) { myCheckMethod(itrator); } string endTime = System.DateTime.String(); } 

I would like to have information when the check is started and when all the lists are checked.

I try something like that:

private void mainMethod() { //1.- get data from the data base //2.- i group the data from the database in many lists. string startTime = System.DateTime.String(); foreach(list<List<long>> iterator in myListOfLists) { TaskEx.Run(() => { myCheckMethod(itrator); }); } string endTime = System.DateTime.String(); } 

But in this case start time and end time is the same, because I don't await the task. So I try this other option:

private void mainMethod() { //1.- get data from the data base //2.- i group the data from the database in many lists. string startTime = System.DateTime.String(); foreach(list<List<long>> iterator in myListOfLists) { TaskEx.Run(() => { myCheckMethod(itrator); }).wait(); } string endTime = System.DateTime.String(); } 

But in this case only is executed one myCheckMethod at the same time, because I am wating to finish one to continue with the next iteration.

So how can I execute many check methods at the same time?