Question

我想将一些现有代码转换为Parallel.Foreach，但我是这个多线程编程的新手，我试图修改代码，但它显示了一些意想不到的行为。每次出错都有。我已经了解了要实现的locking机制，但我不知道如何以及在何处添加lock语句。我也不确定OrganizationRequestCollection是否是线程安全的。

public void ImportDataToCRM(List<Invoice> invoicesList, List<InvoiceLine> invoiceLinesList)
{
  var organizationRequestCollection = new OrganizationRequestCollection();

   foreach (Invoice invoice in invoicesList) //Need to convert this to Parallel.ForEach
   {
      Entity invoiceEntity = EntityMapper.GetEntity<Invoice>(invoice);
      List<InvoiceLine> relatedLines = invoiceLinesList.Where(x => x.InternalId.Equals(invoice.InternalId) && x.DocumentNumber.Equals(invoice.DocumentNumber)).ToList();
      if (relatedLines != null && relatedLines.Count > 0)
      {
           EntityCollection invoiceLineEntityCollection = new EntityCollection();
           foreach (var invoiceLine in relatedLines ) //should this be converted to Parallel.Foreach??
           {
             Entity invoiceLineEntity = EntityMapper.GetEntity<InvoiceLine>(invoiceLine);
             //Lock here ??
             invoiceLineEntityCollection.Entities.Add(invoiceLineEntity);
           }
          //Lock here ??
          invoiceEntity.RelatedEntities.Add(new Relationship("invoice_details"), invoiceLineEntityCollection);
      }
     //Lock here ??
     organizationRequestCollection.Add(new CreateRequest()
                    {
                        Target = invoiceEntity
                    });
   }
}

https://msdn.microsoft.com/en-us/library/microsoft.xrm.sdk.organizationrequestcollection.aspx

https://msdn.microsoft.com/en-us/library/microsoft.xrm.sdk.entitycollection.aspx

Answer 1

1 - 分配到ToList()

时，您不需要List<InvoiceLine> relatedLines =来电

第二 - 很难从代码中扣除，但是如果有可能的话不同的Entity invoiceEntity = EntityMapper.GetEntity<Invoice>(invoice);将返回相同的 invoiceEntity，您肯定需要锁定invoiceEntity.RelatedEntities.Add(..)。另一方面，如果设计保证您的程序永远不会发生，请不要使用lock()。

3 - 关于organizationRequestCollection：它是假设并行的在之外的，但是里面的到Add(..)，所以，是的，使用此设计，您需要lock()那里。

Parallel.Foreach在处理类Collection <t>时

1 个答案: