添加一个孩子Viewport3D异步给人＆QUOT;这个API是带参数访问从错误的上下文中，QUOT。 [英] Adding a child to Viewport3D asynchronously gives "This API was accessed with arguments from the wrong context."

问题描述

当我尝试3D内容添加到Viewport3D，异步，这将导致这个API是从错误的环境参数进行访问。在Tar​​getInvocationException。

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.

的3D-内容从3D-扫描装置的数据生成的。通信与放大器，需要的计算都在一个单独的线程中完成的。首先，我试图从该线程存取权限的viewport3D。我意识到，这应该由GUI线程来完成，所以现在我用这个code：

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);

似乎名为模型的对象是不是在当前线程的上下文。我该如何解决这个问题？有没有办法让模型调度程序的情况下？ 或者是这样，这样做只是没有要走的路在这里的？

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?

推荐答案

这会当过您生成/修改场景对象添加到视口，从不同的线程，然后一个视口被实例化的发生。有一个简单的变通。封装code，更新视口对象到一个函数。将下面的代码片段，和你做。

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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