最近在寫一點東西，因為太久沒有寫了，有點小生疏，因為我要跟網路大量的溝通，但是跟網路溝通的時候 UI 會被 hang 住，會等到連續操作完之後，UI 才會一次更新，這樣感覺很詭異，所以找了一些方法，目前這比較簡單而且成功..筆記一下
這邊我跑十次迴圈，每一次，我都去兩個網站把原始碼拿回來，顯示在 TextBox 裡面，每一個動作我都用 Application.Current.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background, new System.Threading.ThreadStart(delegate 去更新 UI
Full Source Code :
<![CDATA[
for (var i = 1; i <= 10; i++) {
//-- yahoo
Application.Current.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background, new System.Threading.ThreadStart(delegate
{
txtLog.Text += "第" + i + "次擷取網站..\r\n\r\n";
txtLog.Text += "擷取第一個網站\r\n";
txtLog.ScrollToEnd();
}));
WebClient webClient1 = new WebClient();
webClient1.Encoding = System.Text.Encoding.UTF8;
webClient1.Headers.Add("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)");
byte[] byteRes1 = webClient1.DownloadData("http://tw.yahoo.com");
string res1 = System.Text.Encoding.UTF8.GetString(byteRes1);
Application.Current.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background, new System.Threading.ThreadStart(delegate
{
txtLog.Text += res1 + "\r\n";
txtLog.ScrollToEnd();
}));
//--bing
Application.Current.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background, new System.Threading.ThreadStart(delegate
{
txtLog.Text += "擷取第二個網站\r\n";
txtLog.ScrollToEnd();
}));
byte[] byteRes2 = webClient1.DownloadData("http://www.bing.com");
webClient1.Encoding = System.Text.Encoding.UTF8;
string res2 = System.Text.Encoding.UTF8.GetString(byteRes2);
Application.Current.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background, new System.Threading.ThreadStart(delegate
{
txtLog.Text += res2 + "\r\n";
txtLog.ScrollToEnd();
}));
System.Threading.Thread.Sleep(1000);
}
]]>
關鍵是這一段:
Source Code :
<![CDATA[
Application.Current.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background, new System.Threading.ThreadStart(delegate
{
txtLog.Text +="....";
txtLog.ScrollToEnd();
}));
]]>
網路上有看到做法很多，但是效果不是我預期的，這邊就分享一下，順便自己筆記一下..
因為現在 .net Core 3.1 都出了，所以現在範例基本上我都是用 .net Core WPF 去撰寫
reference :
https://stackoverflow.com/questions/7959005/update-ui-from-background-thread/28563279#28563279
