[問題] WPF 物件跨執行緒問題
1.原本的做法
// 有一方法可以create出Canvas物件
private Canvas createCanvas(string canvasString)
{
....
}
// 今天有某個迴圈建立了Canvas的集合
IList<Canvas> canvasList = new List<Canvas>();
for(....)
{
canvasList.Add(createCanvas(..));
}
// 再把Canvas集合加到同一個Canvas, 目前為止是ok的
Canvas canvas = new Canvas();
foreach(Canvas c in canvasList)
{
canvas.Children.Add(c);
}
2. 我遇到的問題...多執行緒的做法
// 在上述的第二個迴圈改為
// inner class
class ThreadParameter
{
public string CanvasContentString { get; set; }
public IList<Canvas> CanvasList { get; set; }
}
void ThreadMethod(object obj)
{
ThreadParameter para = (ThreadParameter)obj;
para.CanvasList.Add(createCanvas(para.CanvasContentString));
}
IList<Canvas> canvasList = new List<Canvas>();
IList<Thread> threadList = new List<Thread>();
for(...)
{
ThreadParameter para = new ThreadParameter() { CanvasList = canvasList,
CanvasContentString = ...};
Thread t = new Thread(new ParameterizedThreadStart(ThreadMethod));
t.SetApartmentState(ApartmentState.STA);
threadList.Add(t);
t.Start(para);
}
foreach(Thread t in threadList)
{
// 等待執行緒跑完
t.Join();
}
// 以上都還沒問題, 以下就是問題, Add到canvas的過程發生Exception
Canvas canvas = new Canvas();
foreach(Canvas c in canvasList)
{
canvas.Children.Add(c);
}
例外訊息為 "呼叫執行緒無法存取此物件，因為此物件屬於另一個執行緒"
不知道怎辦
試了Dispatcher的做法
Canvas canvas = new Canvas();
foreach(Canvas c in canvasList)
{
canvas.Dispatcher.Invoke(DispatcherPriority.Normal, new
AddOverLapXaml(canvas.Children.Add), c);
}
delegate int AddOverLapXaml(UIElement ui);
但仍然有Exception "引動的過程傳回例外"
請問在WPF中
如果是不同Thread所建立的物件想要Add或被Add到UIElementCollection
那個做法是什麼
雖然都用主執行緒可以執行, 但效能真得有差
感恩
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◆ From: 60.251.1.226
※ 編輯: kairy 來自: 60.251.1.226 (10/25 09:50)
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