CefSharp禁止彈出新窗體，在同一視窗打開鏈接，並且支持帶type="POST" target="_blank"的鏈接

1、實現ILifeSpanHandler介面，為了支持帶type="POST" target="_blank"的鏈接，並且為了後面能夠獲取到ChromiumWebBrowser並釋放舊的ChromiumWebBrowser，新窗體還是要讓它彈的，只不過後面會隱藏它，代碼如下：

using CefSharp;
using CefSharp.WinForms;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace MyBrowser
{
    public class CefLifeSpanHandler : CefSharp.ILifeSpanHandler
    {
        public CefLifeSpanHandler()
        {

        }

        public bool DoClose(IWebBrowser browserControl, CefSharp.IBrowser browser)
        {
            if (browser.IsDisposed || browser.IsPopup)
            {
                return false;
            }

            return true;
        }

        public void OnAfterCreated(IWebBrowser browserControl, IBrowser browser)
        {

        }

        public void OnBeforeClose(IWebBrowser browserControl, IBrowser browser)
        {
        }

        public bool OnBeforePopup(IWebBrowser browserControl, IBrowser browser, IFrame frame, string targetUrl, string targetFrameName, WindowOpenDisposition targetDisposition, bool userGesture, IWindowInfo windowInfo, ref bool noJavascriptAccess, out IWebBrowser newBrowser)
        {
            var chromiumWebBrowser = (ExtChromiumBrowser)browserControl;

            ExtChromiumBrowser extBrowser = new ExtChromiumBrowser(targetUrl) { Dock = DockStyle.Fill };

            var windowX = windowInfo.X;
            var windowY = windowInfo.Y;
            var windowWidth = (windowInfo.Width == int.MinValue) ? 600 : windowInfo.Width;
            var windowHeight = (windowInfo.Height == int.MinValue) ? 800 : windowInfo.Height;

            chromiumWebBrowser.Invoke(new Action(() =>
            {
                var popup = new Form
                {
                    Left = windowX,
                    Top = windowY,
                    Width = windowWidth,
                    Height = windowHeight,
                    Text = targetFrameName
                };

                popup.CreateControl();

                var control = new Control();
                control.Dock = DockStyle.Fill;
                control.CreateControl();

                popup.Controls.Add(control);

                popup.Show();

                var rect = control.ClientRectangle;

                windowInfo.SetAsChild(control.Handle, rect.Left, rect.Top, rect.Right, rect.Bottom);

                NewWindowEventArgs e = new NewWindowEventArgs(extBrowser, targetUrl, popup);
                chromiumWebBrowser.OnNewWindow(e);
            }));

            newBrowser = null;
            return false;
        }

    }
}

2、使用ILifeSpanHandler介面：

using CefSharp.WinForms;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms.Integration;

namespace MyBrowser
{
    public class ExtChromiumBrowser : ChromiumWebBrowser
    {
        public ExtChromiumBrowser()
            : base("about:_blank")
        {
            this.LifeSpanHandler = new CefLifeSpanHandler();
            this.DownloadHandler = new DownloadHandler(this);
        }

        public ExtChromiumBrowser(string adress)
            : base(adress)
        {
            this.LifeSpanHandler = new CefLifeSpanHandler();
            this.DownloadHandler = new DownloadHandler(this);
        }

        public event EventHandler<NewWindowEventArgs> StartNewWindow;

        public void OnNewWindow(NewWindowEventArgs e)
        {
            if (StartNewWindow != null)
            {
                StartNewWindow(this, e);
            }
        }
    }
}

3、定義NewWindowEventArgs：

using CefSharp;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace MyBrowser
{
    public class NewWindowEventArgs : EventArgs
    {
        private ExtChromiumBrowser _browser;
        public ExtChromiumBrowser Browser
        {
            get { return _browser; }
            set { value = _browser; }
        }

        private string _url;
        public string Url
        {
            get { return _url; }
            set { value = _url; }
        }

        private Form _form;
        public Form Form
        {
            get { return _form; }
            set { value = _form; }
        }

        public NewWindowEventArgs(ExtChromiumBrowser browser, string url, Form form)
        {
            _url = url;
            _browser = browser;
            _form = form;
        }
    }
}

4、實現StartNewWindow，在StartNewWindow事件中做了三件事，一是替換掉舊的ChromiumWebBrowser，二是釋放掉舊的ChromiumWebBrowser，三是隱藏彈出的新窗體，實際效果可能會看到Windows任務欄的圖標會閃一下消失，那就是彈出的新窗體被隱藏了。這個實現方法比較變態，但是如果不讓新窗體彈出，就不支持帶type="POST" target="_blank"的鏈接，因為沒有把數據POST到伺服器，如果讓新窗體彈出，但是使用新窗體中的Control作為Child，而不new一個新的ChromiumWebBrowser，那麼找不到新ChromiumWebBrowser，雖然它可以正常顯示，但獲取不到它，後面無法釋放。

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    _browser = new ExtChromiumBrowser() { Dock = DockStyle.Fill };
    BindBrowser(_browser);
    _browser.FrameLoadEnd += FrameLoadEnd;
    _browser.Load(_tokenUrl);
    host.Child = _browser;
}

private void BindBrowser(ExtChromiumBrowser browser)
{
    browser.StartNewWindow += (s, e) =>
    {
        this.Dispatcher.BeginInvoke(new Action(() =>
        {
            _browser = e.Browser;
            BindBrowser(e.Browser);
            host.Child = e.Browser;

            e.Browser.FrameLoadStart += (ss, ee) =>
            {
                this.Dispatcher.BeginInvoke(new Action(() =>
                {
                    (ss as ExtChromiumBrowser).Focus();
                }));
            };

            e.Form.Visible = false;
            Task.Factory.StartNew(() =>
            {
                Thread.Sleep(1000);
                this.Dispatcher.BeginInvoke(new Action(() =>
                {
                    e.Form.Dispose();
                    browser.Dispose();
                }));
            });
        }));
    };
}