C# Parallel.ForEach处理和添加到ConcurrentDictionary中

我想把字节转换成pdf格式。因为我想加快进程，使用并行/多线程功能

问题是当MaxDegreeOfParallelism大于1时，它会挂起或中断。我想内存已经被破坏了，有人能给点建议吗

public ConcurrentDictionary<Int64, Byte[]> letterContentDictionary = new ConcurrentDictionary<Int64, Byte[]>();

private void ProcessFilesInParallel()
{
var files = _oldDbContext.LetterData.Where(x => x.ByteContent != null).Select(y => y).Take(100);
Parallel.ForEach(files, new ParallelOptions { MaxDegreeOfParallelism = 4 }, file =>
{
    byte[] byteCompleteLetterPdf = null;
    byteCompleteLetterPdf = ConvertToPdfWithAspose(file.ByteContent);
    letterContentDictionary.TryAdd(file.LetterId, byteCompleteLetterPdf);
});
}

---

尝试先在数组中缓冲DbContext结果，如下所示：

var files = _oldDbContext.LetterData.Where(x => x.ByteContent != null).Select(y => y).Take(100).ToArray();

---

当并行循环中断时，您看到了什么错误？您确定方法ConvertToPdfWithAspose是线程安全的吗？