任务并行库不适用于内部 foreach 循环

基本上我正在尝试使用task一起运行四个函数。这四个函数运行自己的 ForEach 循环。当我执行这些函数时，不断出现错误。"收藏被修改;枚举操作可能无法执行。'"

到目前为止，我已经尝试过的方法：

方法 1：失败

var tasks = new[] 
{ 
    Task.Factory.StartNew(() => function1(publishrequest,nextshiftRq, publishList)),
    Task.Factory.StartNew(() => function2(publishrequest,nextshiftRq, publishList)),
    Task.Factory.StartNew(() => function3(publishrequest,nextshiftRq, publishList)),
    Task.Factory.StartNew(() => function4(publishrequest,nextshiftRq, publishList))
};
Task.WaitAll(tasks);

方法 2：失败

List<Task> tasks = new List<Task>();
tasks.Add(Task.Factory.StartNew(() => function1(publishrequest, nextshiftRq, publishList)));
tasks.Add(Task.Factory.StartNew(() => function2(publishrequest, nextshiftRq, publishList)));
tasks.Add(Task.Factory.StartNew(() => function3(publishrequest, nextshiftRq, publishList)));
tasks.Add(Task.Factory.StartNew(() => function4(publishrequest, nextshiftRq, publishList)));
Task.WaitAll(tasks.ToArray());

方法 3：失败

Parallel.Invoke(
    () = {function1(publishrequest, nextshiftRq, publishList)},
    () = {function2(publishrequest, nextshiftRq, publishList)},
    () = {function3(publishrequest, nextshiftRq, publishList)},
    () = {function4(publishrequest, nextshiftRq, publishList)});

在函数中内部

public void function1(publish p1,nextshift nx, List<publish> pub)
{
    foreach(publish in pub.ToList())
    {
       Evaluate.EvaluateShift(p1.publishShift.ShiftRpt,publish.SectionId);
       Evaluate.EvaluateShift(nx,publish.SectionId);
    }
}

这个函数 1 再次调用另一个函数，其中另一个 foreach 循环正在运行。

//Evaluate.Evaluateshift
Evaluateshift(shiftRpt rpt, int sectionId)
{
 ShiftPI currentShiftI = DataService.GetEntity(GetDataRequest<ShiftPI>.Create(c =>
                c.ShiftID == rpt.ShiftID && c.SectionPanelID == sectionId, "ShiftPI"));
    if(currentShiftI != null)
    {
      List<SectionPanelPI> sectionPanelPIs = DataService.GetAll(GetDataRequest<SectionPanelHSEKPI>.Create(c =>
                        c.SectionPanelID == sectionId, "PI", "PIStatistics")).ToList();

                foreach(sectionPanelPI in sectionPanelPIs)
                {
                 do more stuff....
                }
    }
}

public void function2(publish p1,nextshift nx, List<publish> pub)
{
    foreach(publish in pub.ToList())
    {
    //do stuff
    }
}
public void function3(publish p1,nextshift nx, List<publish> pub)
{
    foreach(publish in pub.ToList())
    {
    //do stuff
    }
}
public void function4(publish p1,nextshift nx, List<publish> pub)
{
    foreach(publish in pub.ToList())
    {
    //do stuff
    }
}