从后台工作更新的ObservableCollection [英] Update ObservableCollection from background Worker

问题描述

我有一个DatGrid，这势必 VAR Result_Full =新的ObservableCollection< IP_DataRow>（）。这是一个包含若干个串放一个简单的类;双变量。没有什么困难的。

我做的，是我读的Excel文件（Telerik的RadSpreadProcessing），它解析行到我的课堂。我这样做的一个线程，这样用户界面不会被阻断。我也遇到了一些问题，但：

1）在相当长的过程，读取Excel中我不能使用 REF 关键字文件（因为Result_Full是绑定到一个DataGrid公共财产），但我必须创建临时的ObservableCollection< IP_DataRow>（），其中的值放置。一旦这个过程完成后我运行下面的脚本复制值：

 的foreach（在tmpFull VAR项）
 {
 InvokeOnUIThread（（）=> 
 {
 Result_Full.Add（项目）; 
}）; 
} 
  

的我想什么做的，就是能看到在实时（如果可能）的项目是如何被添加到集合在我的DataGrid中。的

由于我使用.NET 4.5我试图执行 BindingOperations.EnableCollectionSynchronization 这已在一些其他职位的建议，但我无法弄清楚如何我的UI鲍尔德收集的 Result_Full 绑定到一个临时使用流程。

2）即使当前的设置，当（我的用户界面下），我移动到我的选项，其中包含的DataGrid（我的DataGrid是在不同的TabPage）和我尝试新的项目加入到与上述代码的集合，它会返回一个错误说：调用线程不能因为不同的线程拥有它访问该对象，这是相当奇怪的，因为<。 STRONG> InvokeOnUIThread 不是别的， Dispatcher.Invoke（），这应该是线程安全的？

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编辑：显示更多的代码：

这是这个过程中我打电话从BackgroundWorker的：

 公共无效ProcessFile（）
 {
变种tmpError =新的ObservableCollection< IP_DataRow>（ ）; 
变种tmpFull =新的ObservableCollection< IP_DataRow>（）; 
 
变种_reader =新IP_ExcelReader（sExcelPath，楼盘tmpError，裁判tmpFull）; 
串sResult = _reader.ReadExcelFile（）; 
如果（sResult！=的String.Empty）
 {
 System.Windows.MessageBox.Show（选择Excel文件错误处理！+ Environment.NewLine + Environment.NewLine +错误信息：+ Environment.NewLine + sResult）; 
} 
 
的foreach（在tmpError VAR项目）//填充错误列表
 {
 IP_InvokeOnUIThread（（）=> 
 {
 Result_Error.Add（项目）; 
}）; 
} 
 
的foreach（在tmpFull VAR项目）//填充完整列表
 {
 IP_InvokeOnUIThread（（）=> 
 {
 Result_Full.Add（项目）; 
}）; 
} 
 
 OnPropertyChanged（Result_Full）; 
 // OnPropertyChanged（Result_Error）; 
 
 iSelectedTabIndex = 1; 
 
} 
  

在这里你可以看到，我必须创建临时集合 tmpError，tmpFull 在这里我收集我的数据。在过程结束时，我手动值复制到我的必然的DataGrid主集合。我想改变这一点，这意味着值复制到过程中的主要集合（不是暂时的），使用户可以在值如何添加到集合实时看到。

PS2：
为UKNOWN理由给我，其中一个问题在我的 InvokeOnUIThread 通话撒谎。有一次，我从 App.Current.Dispatcher.Invoke（动作）改变; 到 App.Current.Dispatcher.BeginInvoke（动作）; 错误是 ..不同的线程拥有它停止。

解决方案

1. 您可以使用BackgroundWorker的，而不是线程，因为它去报告进度。
   这里是一个简单的教程


2. 我认为，简单地调用调度员将使用一种背景下，这是不是UI线程在你的案件线索。尝试 Application.Current.Dispatcher 而不是

在总之，我相信你应该请执行以下操作：

1. 在UI线程创建公共的ObservableCollection并将其绑定到数据网格


2. 创建后台工作。设置为true报告。订阅ReportProgress和DoWork的事件。


3. 运行工人异步


4. 在DoWork的处理程序创建一个列表，且读取值的一定量的它。当你到达一定量，比方说百，通话（发件人为BackgroundWorker的）.ReportProgress 方法，在事件参数传递这个集合已填充。


5. 在报告进度处理程序中，你已经通过throught事件参数列表填充您的ObservableCollection


6. 步骤4 - 5被重复，直到一切都做

I have a DatGrid, which is bound to var Result_Full = new ObservableCollection<IP_DataRow>(). This is a simple class containing several string & double variables. Nothing difficult.

What I do, is that I read an Excel File (with Telerik RadSpreadProcessing), which parses rows into my class. I do this on a thread so that the UI is not blocked. I have encountered a few problems though:

1) I cannot use ref keyword in a long process which reads excel file (because Result_Full is a public property bound to a DataGrid), but I have to create temporary ObservableCollection<IP_DataRow>(), where the values are placed. Once the process has finished I run the following script for copying the values:

        foreach (var item in tmpFull)
        {
            InvokeOnUIThread(() =>
            {
                Result_Full.Add(item);
            });
        }

What I would like to do, is to be able to see in a real time (if possible) how items are being added to the collection in my DataGrid.

As I am using .Net 4.5 I tried to implement BindingOperations.EnableCollectionSynchronization as was suggested by some other post, yet I could not figure out how to bind my UI bould collection Result_Full to temporary used in a process.

2) Even with the current setup, when (under my UI) I move to my Tab which contains DataGrid (my DataGrid is on a different TabPage), and I try to add new item to the collection with the above mentioned code, it returns an error saying: The calling thread cannot access this object because a different thread owns it., which is rather weird, as InvokeOnUIThread is nothing else but Dispatcher.Invoke(), which should be thread safe?

Any help would be highly appreciated.

EDIT: Showing more code:

This is the process I call from BackgroundWorker:

    public void ProcessFile()
    {
        var tmpError = new ObservableCollection<IP_DataRow>();
        var tmpFull = new ObservableCollection<IP_DataRow>();

        var _reader = new IP_ExcelReader(sExcelPath, ref tmpError, ref tmpFull);
        string sResult = _reader.ReadExcelFile();
        if (sResult != string.Empty)
        {
            System.Windows.MessageBox.Show("Error processing selected Excel File!" + Environment.NewLine + Environment.NewLine + "Error message:" + Environment.NewLine + sResult);
        }

        foreach (var item in tmpError)//populates error list
        {
            IP_InvokeOnUIThread(() =>
            {
                Result_Error.Add(item);
            });
        }

        foreach (var item in tmpFull)//populates full list
        {
            IP_InvokeOnUIThread(() =>
            {
                Result_Full.Add(item);
            });
        }

        OnPropertyChanged("Result_Full");
        //OnPropertyChanged("Result_Error");

        iSelectedTabIndex = 1;

    }

Here you can see, that I have to create temporary collection tmpError, tmpFull where I gather my data. At the end of process, I manually copy values into my main collections bound to DataGrid. I would like to change this, meaning that values are copied to the main collection (not temporary ones) during the process, so that user can see in a real time how values are added to the collection.

P.S.2: for uknown reason to me, one of the problems lied in my InvokeOnUIThread call. Once I changed from App.Current.Dispatcher.Invoke(action); to App.Current.Dispatcher.BeginInvoke(action); error with ..different thread owns it stopped.

解决方案

1. You can use BackgroundWorker instead of thread, to report progress as it goes. Here is a simple tutorial
2. I believe that simply calling Dispatcher will use thread of a context, which is not UI-thread in your case. Try Application.Current.Dispatcher instead

In short, I believe you should do the following:

1. Create public ObservableCollection in UI-thread and bind it to DataGrid
2. Create a background worker. Set reporting to true. Subscribe to ReportProgress and DoWork events.
3. Run worker async
4. In DoWork handler create a list and read some amount of values to it. As you reach some amount, let's say a hundred, call (sender as BackgroundWorker).ReportProgress method, passing in event args this collection you have populated.
5. In report progress handler, populate your ObservableCollection from a list you've passed throught event args.
6. Steps 4 - 5 are repeated until everything is done

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