Parallel.ForEach 意外退出，无异常

Question

I am running a .NET 4.7 C# console application in which I am iterating through a collection of files (list of strings with file paths.

I want to run an operation on each file in parallel.

private void LaunchComparators()
{
    //1) Get Trade Files
    var files = GetTradeFiles();

    //2) Run comparisons
    try
    {
        Parallel.ForEach(files, file => LaunchComparator(file));
    }
    catch (Exception ex)
    {
        Log.Error(ex.Message);
        throw ex;
    }
    //2 Write Results
    WriteResults();
}

private void LaunchComparator(string file)
{
    var comparator = new TradeComparator();
    var strategyComparisonOutput = comparator.ComparePerStrategy(file);

}

While running the comparison, the first comparison completes and then the program abruptly stops without any exceptions.

I am not sure what I should do differently here, so that the files are all processed individually.

I am new to parallel programming/threading. Any help appreciated.

Answer 1

Parallel For and ForEach operations do not re-throw exception that occur inside the loop. If you don't add exception handling inside the loop the exceptions are lost and the loop just terminates.

Here is a link to an article on how to handle exception inside of Parallel processing loops:

https://docs.microsoft.com/en-us/dotnet/standard/parallel-programming/how-to-handle-exceptions-in-parallel-loops