使用SyncLock同步对List(of T)的访问 [英] Using SyncLock to synchronize access to List(of T)

问题描述

我有一个包含在多线程应用程序中使用的List(of T)的类.我有三种获取，添加和删除方法，这些方法用于访问和修改List(of T).每当我为所需对象查询以及添加或删除对象时，我都使用SyncLock锁定m_List. 但是我是否好奇通过添加对象或删除对象时简单地锁定m_List(而不是在搜索所需对象时)来提高性能?

I have a class that contains a List(of T) used in a multithreaded application. I have three methods Get, Add and Remove where these access and modify the List(of T). I was using SyncLock to lock m_List any time I queried it for the desired object as well as when I added or removed objects. However I'm curious as to if there is a performance gain by simply locking m_List when I add an object or remove an object as opposed to when I'm searching for a desired object?

Public Shared sub Add(SomeObject as object)

     SyncLock ctype(m_List, IList).SyncRoot

         m_List.add(SomeObject)

     end SyncLock

end sub

Public Shared sub Remove(SearchString as string)

     SyncLock ctype(m_List, IList).SyncRoot

           m_List.RemoveAll(function(o as SomeObject) o.SomeProperty = SearchString)

     end SyncLock
end Function

Public Shared Function Get(SearchString as string) as SomeObject
     'The Commented out code is what I am thinking of removing...
     'SyncLock ctype(m_List, IList).SyncRoot

     Dim FoundObjectList = m_List.where(function(o as SomeObject) o.SomeProperty = SearchString)

    if FoundObjectList.count > 0 then 

       If FoundObjectList(0).CreateDate < Now.AddMinutes(5) then
          Remove(FoundObjectList(0).SomeProperty)
          Return nothing
       end if
    else
         Return FoundObjectList(0)

    End if

   Return Nothing
'end SyncLock
end sub

推荐答案

如果您尝试遍历列表并在执行此操作时允许另一个线程添加条目，则会得到一个InvalidOperationException，它是就如此容易.我的猜测是那不是您想要的行为.

If you try to iterate over the list and allow another thread to add an entry while you're doing so, you'll get an InvalidOperationException, it's as simple as that. My guess is that's not the behaviour you want.

List<T>根本不支持从一个线程进行写入，而不能同时从另一个线程进行读取-特别是不遍历该列表.

List<T> simply doesn't support writing from one thread and reading from another at the same time - particularly not iterating over the list.

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