如何在使用Windows.Forms.WebBrowser控件浏览Web文档的同时释放内存

Question

The following code, run in a windows form, creates a WebBrowser control and navigates to a number of URLs. Each time a URL is navigated to the memory consumed by the application increases and never seems to get released. In my case the memory consumed rises from ~10 Mb to ~45 Mb navigating just 4 documents. I need to navigate several hundred documents which quickly causes all the physical memory to be used.

How do I release the resources used by the WebBrowser control?

    private void ProcessDocs()
    {
        Random rnd = new Random();
        DateTime dtWaitUntil = DateTime.Now;
        string[] arrInputUrl = new string[] { "http://www.google.co.uk/", "http://www.google.com/", "http://www.yahoo.com/", "http://www.amazon.co.uk/" };

        for (int i = 0; i < arrInputUrl.Length; i++)
        {
            using (WebBrowser objWebBrowser = new WebBrowser())
            {
                string txtInputUrl = arrInputUrl[i];
                tboxTestingOutput.Text += "\r\n" + txtInputUrl;

                objWebBrowser.ScriptErrorsSuppressed = true;
                objWebBrowser.Navigate(txtInputUrl);

                //Should do this a better way, but, wait 10 secs for document to complete.
                //Would use objWebBrowser.DocumentCompleted event
                //but it seems to fire several times per document load!!!
                dtWaitUntil = DateTime.Now.AddSeconds(10);

                do
                {
                    Application.DoEvents();
                } while (DateTime.Now < dtWaitUntil);

                //Do whatever I need to with the document contents
                //...
                //...
            }
        }

        tboxTestingOutput.Text += "\r\nFinished";
    }

Answer 1

Although I wouldn't completely recommend it, P/Invoke SetProcessWorkingSetSize with -1 should force an empty of the process working set, for example:

[DllImport("kernel32.dll")]
static extern bool SetProcessWorkingSetSize(IntPtr handle, int minSize, int maxSize);

SetProcessWorkingSetSize(Process.GetCurrentProcess().Handle,-1,-1);

Read more here:

http://msdn.microsoft.com/en-us/library/windows/desktop/ms686234(v=vs.85).aspx