向 Viewport3D 异步添加子项会给出“此 API 是使用来自错误上下文的参数访问的。”

发布于 2024-08-12 20:49:40 字数 855 浏览 4 评论 0原文

当我尝试将 3D 内容异步添加到 Viewport3D 时，会导致“使用来自错误上下文的参数访问此 API”。在 TargetIncationException 中。

3D 内容是根据 3D 扫描设备的数据生成的。所需的通信和计算是在单独的线程中完成的。首先，我尝试从该线程访问 viewport3D。我意识到这应该由 GUI 线程完成，所以现在我使用这段代码：

        ModelVisual3D model = new ModelVisual3D();
        model.Content = scanline;

        DispatcherOperation dispOp = this.viewport.Dispatcher.BeginInvoke(
            new AddModelDelegate(StartAddModel), model);
    }
    private void StartAddModel(ModelVisual3D model)
    {
        this.viewport.Children.Add(model); 
        //model is not in the context of this current thread. 
        //Throws exception: "This API was accessed with arguments from the wrong context."
    }

    private delegate void AddModelDelegate(ModelVisual3D model);

看起来名为“model”的对象不在当前线程的上下文中。我该如何解决这个问题？有没有办法让模型进入调度程序的上下文？或者这种做法不适合这里？

原文

When I try to add 3D-content to a Viewport3D, asynchronously, this results in "This API was accessed with arguments from the wrong context." in a TargetInvocationException.

The 3D-content is generated from the data of a 3D-scanning device. The communication&calculations needed for that are done in a separate thread. First, I tried to acces the viewport3D from that thread. I realized this should be done by the GUI-thread, so now I use this code:

        ModelVisual3D model = new ModelVisual3D();
        model.Content = scanline;

        DispatcherOperation dispOp = this.viewport.Dispatcher.BeginInvoke(
            new AddModelDelegate(StartAddModel), model);
    }
    private void StartAddModel(ModelVisual3D model)
    {
        this.viewport.Children.Add(model); 
        //model is not in the context of this current thread. 
        //Throws exception: "This API was accessed with arguments from the wrong context."
    }

    private delegate void AddModelDelegate(ModelVisual3D model);

It seems that the object named "model" is not in the context of the current thread. How can I fix this? Is there a way to get the model to the context of the Dispatcher?
Or is this way of doing this just not the way to go here?

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决绝 2024-08-19 20:49:40

当您从实例化视口的不同线程生成/修改场景对象以添加到视口时，就会发生这种情况。有一个简单的解决方法。将更新 Viewport 对象的代码封装到一个函数中。插入以下代码片段即可完成。

private delegate void MyFunctionDelegate();

void MyFunction()
{
     if(!Application.Current.Dispatcher.CheckAccess())
     {
         Application.Current.Dispatcher.Invoke(new MyFunctionDelegate(MyFunction));
         return; // Important to leave the culprit thread
     }
     .
     .
     .
     this.Viewport3D.Children.Remove(model);
     MyModifyModel(model);
     this.Viewport3D.Children.Add(model); 
}

This will occur when ever you generate/modify scene objects to add to Viewport, from a different thread then the one Viewport was instantiated on. There is a simple work around. Encapsulate the code that updates Viewport objects into a function. Insert the following snippet and you are done.

private delegate void MyFunctionDelegate();

void MyFunction()
{
     if(!Application.Current.Dispatcher.CheckAccess())
     {
         Application.Current.Dispatcher.Invoke(new MyFunctionDelegate(MyFunction));
         return; // Important to leave the culprit thread
     }
     .
     .
     .
     this.Viewport3D.Children.Remove(model);
     MyModifyModel(model);
     this.Viewport3D.Children.Add(model); 
}

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