我的应用程序需要根据请求调用(屏幕外)浏览器,并在完成后进行清理。
所以我创建了一个屏幕外的浏览器
public class OffScreenBrowser
{
private static ChromiumWebBrowser _browser;
private static CefSettings _settings;
public void Load(string url,System.Drawing.Size size)
{
if (Cef.IsInitialized) return;
Init(new BrowserProcessHandler());
_browser = new ChromiumWebBrowser(url) {Size = size};
_browser.NewScreenshot += _browser_NewScreenshot;
}
public System.Windows.Controls.Image BrowserImage { get; set; }
public Action NewScreenShotAction { get; set; }
private void _browser_NewScreenshot(object sender, EventArgs e)
{
var bitmap = _browser.ScreenshotOrNull();
Application.Current.Dispatcher.Invoke(new Action(() =>
{
using (MemoryStream memory = new MemoryStream())
{
bitmap.Save(memory, ImageFormat.Png);
memory.Position = 0;
BitmapImage bitmapImage = new BitmapImage();
bitmapImage.BeginInit();
bitmapImage.StreamSource = memory;
bitmapImage.CacheOption = BitmapCacheOption.OnLoad;
bitmapImage.EndInit();
BrowserImage = new System.Windows.Controls.Image() {Source = bitmapImage};
NewScreenShotAction();
}
}));
}
public void Close()
{
_browser.NewScreenshot -= _browser_NewScreenshot;
_browser.Dispose();
_settings.Dispose();
Cef.Shutdown();
}
public static void Init(IBrowserProcessHandler browserProcessHandler)
{
_settings = new CefSettings();
if (!Cef.Initialize(_settings, true, browserProcessHandler))
throw new Exception("Unable to Initialize Cef");
}
}
这个想法是:单击一个按钮创建浏览器,然后单击另一个按钮关闭浏览器
private OffScreenBrowser offScreenBrowser;
private void OPen_OnClick(object sender, RoutedEventArgs e)
{
var address = @"https://www.google.co.uk";
var width = 200;
var height = 100;
var windowSize = new System.Drawing.Size(width, height);
offScreenBrowser = new OffScreenBrowser();
offScreenBrowser.Load(address, windowSize);
offScreenBrowser.NewScreenShotAction = () =>
{
Browser.Content = offScreenBrowser.BrowserImage;
};
}
private void Close_OnClick(object sender, RoutedEventArgs e)
{
offScreenBrowser.Close();
}
第一次单击,一切正常。在单击关闭时,似乎清理很好。
但是当我第二次单击打开按钮时,出现如下异常
"An unhandled exception of type 'System.AccessViolationException' occurred in CefSharp.Core.dll
Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
我究竟做错了什么?
最佳答案
这是Chromium框架的局限性。
每个流程只能对CEF进行一次初始化/关闭,
有关更多详细信息,请参见Need to Know/Limitations,这是对底层Chromium框架的限制。