介绍
这是一个很长的问题!您将在开始时找到有关问题的一些背景,然后是代码示例,这些示例已被简化以用于表示和之后的问题。请按照您认为适合您的任何顺序阅读!
背景资料
我正在为与 STA COM 通信的应用程序编写概念验证部分。这部分应用程序需要在单线程单元 (STA) 上下文中运行,以便与所述 STA COM 通信。应用程序的其余部分在 MTA 上下文中运行。
当前状态
到目前为止,我想出的是创建一个包含循环的通信类,在 STA 中运行。while
需要中继到 COM 对象的工作从外部通过ConcurrentQueue
. 然后工作项在 while 循环中出列并执行工作。
代码上下文
通讯类
这是一个static
类,包含一个循环,旨在在 STA 状态下运行并检查是否需要由 COM 完成某些工作并将工作分派给处理程序。
static class Communication
{
#region Public Events
/// This event is raised when the COM object has been initialized
public static event EventHandler OnCOMInitialized;
#endregion Public Events
#region Private Members
/// Stores a reference to the COM object
private static COMType s_comObject;
/// Used to queue work that needs to be done by the COM object
private static ConcurrentQueue<WorkUnit> s_workQueue;
#endregion Private Members
#region Private Methods
/// Initializes the COM object
private static void InternalInitializeCOM()
{
s_comObject = new COMType();
if (s_comObject.Init())
{
OnCOMInitialized?.Invoke(null, EventArgs.Empty);
}
}
/// Dispatches the work unit to the correct handler
private static void HandleWork(WorkUnit work)
{
switch (work.Command)
{
case WorkCommand.Initialize:
InternalInitializeCOM();
break;
default:
break;
}
}
#endregion Private Methods
#region Public Methods
/// Starts the processing loop
public static void StartCommunication()
{
s_workQueue = new ConcurrentQueue<WorkUnit>();
while (true)
{
if (s_workQueue.TryDequeue(out var workUnit))
{
HandleWork(workUnit);
}
// [Place for a delaying logic]
}
}
/// Wraps the work unit creation for the task of Initializing the COM
public static void InitializeCOM()
{
var workUnit = new WorkUnit(
command: WorkCommand.Initialize,
arguments: null
);
s_workQueue.Enqueue(workUnit);
}
#endregion Public Methods
}
工作指挥
此类描述需要完成的工作以及可能提供的任何参数。
enum WorkCommand
{
Initialize
}
工作单位
此枚举定义了 COM 可以执行的各种任务。
class WorkUnit
{
#region Public Properties
public WorkCommand Command { get; private set; }
public object[] Arguments { get; private set; }
#endregion Public Properties
#region Constructor
public WorkUnit(WorkCommand command, object[] arguments)
{
Command = command;
Arguments = arguments == null
? new object[0]
: arguments;
}
#endregion Constructor
}
所有者
这是拥有或生成Communication
COM 的类的示例,并且是对应用程序其余部分使用的抽象Communication
。
class COMController
{
#region Public Events
/// This event is raised when the COM object has been initialized
public event EventHandler OnInitialize;
#endregion Public Events
#region Constructor
/// Creates a new COMController instance and starts the communication
public COMController()
{
var communicationThread = new Thread(() =>
{
Communication.StartCommunication();
});
communicationThread.SetApartmentState(ApartmentState.STA);
communicationThread.Start();
Communication.OnCOMInitialized += HandleCOMInitialized;
}
#endregion Constructor
#region Private Methods
/// Handles the initialized event raised from the Communication
private void HandleCOMInitialized()
{
OnInitialize?.Invoke(this, EventArgs.Emtpy);
}
#endregion Private Methods
#region Public Methods
/// Requests that the COM object be initialized
public void Initialize()
{
Communication.InitializeCOM();
}
#endregion Public Methods
}
问题
现在,看一下Communication.StartCommunication()
方法,更具体地说是这部分:
...
// [Place for a delaying logic]
...
如果此行替换为以下内容:
await Task.Delay(TimeSpan.FromMilliseconds(100)).ConfigureAwait(false);
// OR
await Task.Delay(TimeSpan.FromMilliseconds(100)).ConfigureAwait(true);
在检查最后一站 -Communication.InternalInitializeCOM()
线程的公寓似乎是MTA。
但是,如果延迟逻辑更改为
Thread.Sleep(100);
该CommunicationInternalInitializeCOM()
方法似乎在STA状态下执行。
检查由Thread.CurrentThread.GetApartmentState()
.
问题
谁能向我解释为什么会Task.Delay
破坏 STA 状态?还是我在这里做其他错误的事情?
谢谢!
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