如何在线程中可观察的集合中复制列表

问题描述

我有一个背景工作人员填写/填写一个列表，并在填写和编辑列表后，将其列入可观察列表中：

  this.OBSMailCountList = new ObservableCollection< IMailCount>（_ allMailCounts）; 
  

问题是Collection被绑定到Live Diagramm，在List中复制之后

错误：

值不能为NULL / p>

我的问题是：

如何复制具有绑定的可观察集合线程？

解决方案

您的问题是您有 _allMailCounts == null 当时你调用可观察的收集构造函数。您可以检查 null 如下

  if（_allMailCounts！= null ）
 OBSMailCountList = new ObservableCollection< IMailCount>（_ allMailCounts）; 
  

以下是有关如何使用 ObservableCollection 从另一个步骤：

---

绑定到像往常一样定义的可观察集合

  ObservableCollection< IMailCount> _collection = new ObservableCollection< IMailCount>（）; 
 public ObservableCollection< IMailCount>集合
 {
 get {return _collection; } 
 set 
 {
 _collection = value; 
 OnPropertyChanged（）; 
} 
} 
  

在另一个线程中，以这种方式工作： p>

  //在UI线程中创建一个列表
列表< IMailCount> collection = null; 
 Dispatcher.Invoke（（）=> collection = new List< IMailCount>（_ collections））; 
 
 //在UI线程中完成工作集属性
 Dispatcher.InvokeAsync（（）=> Collection = new ObservableCollection< IMailCount>（collection））; 
  

I have a background worker who fills/refills a List and After refilling and editing the List I copy this list in an Observable List:

this.OBSMailCountList = new ObservableCollection<IMailCount>(_allMailCounts);

The Problem is that the Collection is bind to an Live Diagramm and after the Copy in the List I get the

Error:

"The Value can not be NULL".

My Question is:

How to Copy an Observable Collection with Bindings in a Thread ?

解决方案

Your problem is that you have _allMailCounts == null at the moment you call observable collection constructor. You can check for null like this

if(_allMailCounts != null)
    OBSMailCountList = new ObservableCollection<IMailCount>(_allMailCounts);

Below is the answer on question "how to work with ObservableCollection from another tread":

---

Bind to observable collection defined as usual

ObservableCollection<IMailCount> _collection = new ObservableCollection<IMailCount>();
public ObservableCollection<IMailCount> Collection
{
    get { return _collection; }
    set
    {
        _collection = value;
        OnPropertyChanged();
    }
}

In another thread do work in this manner:

// create a copy as list in UI thread
List<IMailCount> collection = null;
Dispatcher.Invoke(() => collection = new List<IMailCount>(_collection));

// when finished working set property in UI thread
Dispatcher.InvokeAsync(() => Collection = new ObservableCollection<IMailCount>(collection));

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