[英]UI still freezes using backgroundWorker
I'm quite new to WPF. 我对WPF很陌生。 I am developing a PRISM application and want to update the UI when an enumerable is updated. 我正在开发PRISM应用程序,并希望在更新枚举时更新UI。 I use a backgroundWorker in my modelView to update the enumaration. 我在modelView中使用backgroundWorker更新了枚举。 it all works fine until the enumeration it self gets updated and then the UI freezes!! 一切正常,直到它自身的枚举被更新,然后UI冻结! a friend told my I might be able to use the yield
keyword but I didn't quite figured it out. 一位朋友告诉我,我也许可以使用yield
关键字,但我不太清楚。
Here is the code: 这是代码:
public void ChangeCollection()
{
BackgroundWorker worker = new BackgroundWorker();
// Set workers job
worker.DoWork += (sender, e) =>
{
RunOnUIThread(() => IsBusy = true);
e.Result = GetPrimes();
};
// On Complete
worker.RunWorkerCompleted += (sender, e) =>
{
RunOnUIThread(() =>
{
IsBusy = false;
// HERE IS WHERE IT GETS STUCK
Numbers = new ObservableCollection<int>
((IEnumerable<int>)e.Result);
});
};
// Start background operation
worker.RunWorkerAsync();
}
public ObservableCollection<int> Numbers
{
get {return _Numbers;}
set
{
_Numbers = value;
RaisePropertyChanged(() => Numbers);
}
}
public IEnumerable<int> GetPrimes()
{
List<int> primes = new List<int>();
for (int i = 0; i < 100000; i++)
{
bool IsPrime = true;
for (int j = 2; j < i; j++)
{
if (i % j == 0)
IsPrime = false;
}
if (IsPrime)
primes.Add(i);
}
return primes;
}
Any advise would be greatly appriciated! 任何建议将不胜感激!
Thanks, Omri 谢谢Omri
yield
won't help you here. yield
不会在这里帮助您。 RunWorkerCompleted
executes on the UI thread. RunWorkerCompleted
在UI线程上执行。 Apparently instantiating the ObservableCollection<int>
is taking a long time. 显然实例化ObservableCollection<int>
花费很长时间。 The simplest solution may be to move the instantiation to the background thread ( DoWork
) as well. 最简单的解决方案可能是将实例也移动到后台线程( DoWork
)。 It could also be a PropertyChanged
event handler that is taking a long time, in which case it should also run on a background thread. 它也可能是花费很长时间的PropertyChanged
事件处理程序,在这种情况下,它也应该在后台线程上运行。
A few things here. 这里有几件事。 1) Your worker and its delegates should be created when your object containing it is instantiated. 1)实例化包含它的对象时,应创建您的工作程序及其委托。
public class ViewModel
{
BackgroundWorker _primeWorker;
public ViewModel()
{
_primeWorker = new BackgroundWorker;
_primeWorker.DoWork += ...
}
public void AddSomeNumbers()
{
if(_primerWorker.IsBusy == false)
_primeWorker.RunWorkerAsync();
}
}
2) Your collection should be instantiated when the object containing it is instantiated to avoid a null exception being thrown should the object using this class calls the get
. 2)当实例化包含它的对象时,应该实例化您的集合,以避免使用该类的对象调用get
引发null异常。
3) Adding that many items would cause slowness due to each time you add a number an event is fired that the UI thread has to handle. 3)添加许多项会导致速度变慢,这是因为每次添加数字都会触发UI线程必须处理的事件。
This link has more info to help you out. 此链接有更多信息可以帮助您。 http://msdn.microsoft.com/en-us/library/cc221403(v=vs.95).aspx http://msdn.microsoft.com/zh-CN/library/cc221403(v=vs.95).aspx
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