我将如何在工作线程中执行它？ [英] How would i execute it in worker thread ?

问题描述

考虑下面的代码，我通过读取MS Access数据库将节点添加到树视图控件。


显然，如果我在一个单独的线程中执行，我会得到关于控件的异常从创建它的线程以外的线程访问。


现在每当我向树中添加一个节点时，我都可以将它解压缩到这样的GUI线程

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解决方案

您的代码未格式化且非常难以阅读。


更新c时从一个线程上对WinForm进行ontrols，使用Control.Invoke的派生来更新控件。


更新WinForm控件的一种非常安全的方法是使用BackgroundWorker生成线程组件。


这是一篇很好的文章讨论线程更新WinForms：
Windows窗体中的线程。

这是格式化的代码：

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我会提出两点建议，但我没有写一个例子来证明它们能正常工作。如果他们不这样做，请告诉我。


建议＃1：

• 在GUI中实例化初始TreeView。
• 将其作为参数传递到一个BackgroundWorker线程（也在GUI中创建）。
• 让线程填充节点（您发布的代码）。
• 处理RunWorkerCompleted事件以更新实际的显示已填写的TreeView。
• 如何使用：在后台运行操作。

建议＃2：

如果在执行后仍然收到线程访问冲突如上所述，然后向GUI添加一个辅助方法，该方法将在线程中创建的节点克隆到GUI TreeView中的节点。这可以是一个简单的回归循环，并且应该快速运行，因为您已经在线程中执行了数据访问部分。


但是，我真的相信第二步不是必需的。如果从GUI生成BackgroundWorker线程，则保证在与GUI本身相同的线程上执行。它在Component命名空间中专门提供，以消除与WinForms相关的交叉线程问题。

Consider the following code in which i add nodes to a treeview control by reading an MS Access database.

Obviously, if I execute in a seperate thread I will get exception about control accessed from a thread other than the one in which it is created.

Now whenever I am adding one node to the tree I could marshel it to the GUI thread like this

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解决方案

Your code is unformatted and very difficult to read.

When updating controls on a WinForm from a thread, use a derivative of Control.Invoke to update the control.

A very safe way to update controls on a WinForm is to spawn the thread using a BackgroundWorker component.

Here is a great article discussing thread updating WinForms:
Threading in Windows Forms.

Here is the formatted code :

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I will make two suggestions, but I have not written an example to prove they will work correctly. Let me know if they do not.

Suggestion #1:

• Instantiate the initial TreeView in the GUI.
• Pass it as a parameter to a BackgroundWorker thread (also created in the GUI).
• Have the thread fill in the nodes (your posted code).
• Handle the RunWorkerCompleted event to update the actual display of the filled-in TreeView.
• How To: Run an Operation in the Background.

Suggestion #2:
If you still receive a thread access violation after implementing the above, then add a helper method to your GUI which will clone the nodes created in the thread to the nodes in your GUI TreeView. This can be a simple recusion loop and should run quickly, since you have already performed the data access part in your thread.

However, I truly believe the second step will not be necessary. If you spawn a BackgroundWorker thread from the GUI, it is guaranteed to execute on the same thread as the GUI itself. It is provided in the Component namespace specifically to eliminate the cross-threading issues associated with WinForms.

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