WinForms - Add LifeSpanHandler.OnBeforePopupCreated

- Allow for cancelling of popup creation

browser.LifeSpanHandler = CefSharp.WinForms.Handler.LifeSpanHandler
	.Create()
	.OnBeforePopupCreated((chromiumWebBrowser, b, frame, targetUrl, targetFrameName, targetDisposition, userGesture, browserSettings) =>
	{
		//Can cancel opening popup based on Url if required.
		if(targetUrl?.StartsWith(CefExample.BaseUrl + "/cancelme.html") == true)
		{
			return PopupCreation.Cancel;
		}

		return PopupCreation.Continue;
	})

Author: amaitland

CefSharp.WinForms.Example/BrowserTabUserControl.cs

@@ -69,8 +69,18 @@ public BrowserTabUserControl(Action<string, int?> openNewTab, string url, bool m
             //The CefSharp.WinForms.Handler.LifeSpanHandler implementation
             //allows for Popups to be hosted in Controls/Tabs
             //This example also demonstrates docking DevTools in a SplitPanel
-            browser.LifeSpanHandler = LifeSpanHandler
+            browser.LifeSpanHandler = CefSharp.WinForms.Handler.LifeSpanHandler
                 .Create()
+                .OnBeforePopupCreated((chromiumWebBrowser, b, frame, targetUrl, targetFrameName, targetDisposition, userGesture, browserSettings) =>
+                {
+                    //Can cancel opening popup based on Url if required.
+                    if(targetUrl?.StartsWith(CefExample.BaseUrl + "/cancelme.html") == true)
+                    {
+                        return PopupCreation.Cancel;
+                    }
+
+                    return PopupCreation.Continue;
+                })
                 .OnPopupCreated((ctrl, targetUrl) =>
                 {
                     //Don't try using ctrl.FindForm() here as

CefSharp.WinForms/Handler/LifeSpanHandler.cs

@@ -10,6 +10,25 @@
 
 namespace CefSharp.WinForms.Handler
 {
+    /// <summary>
+    /// Called <b>before</b>the popup is created, can be used to cancel popup creation if required
+    /// or modify <see cref="IBrowserSettings"/>.
+    /// It's important to note that the methods of this interface are called on a CEF UI thread,
+    /// which by default is not the same as your application UI thread.
+    /// </summary>
+    /// <param name="chromiumWebBrowser">the ChromiumWebBrowser control</param>
+    /// <param name="browser">The browser instance that launched this popup.</param>
+    /// <param name="frame">The HTML frame that launched this popup.</param>
+    /// <param name="targetUrl">The URL of the popup content. (This may be empty/null)</param>
+    /// <param name="targetFrameName">The name of the popup. (This may be empty/null)</param>
+    /// <param name="targetDisposition">The value indicates where the user intended to
+    /// open the popup (e.g. current tab, new tab, etc)</param>
+    /// <param name="userGesture">The value will be true if the popup was opened via explicit user gesture
+    /// (e.g. clicking a link) or false if the popup opened automatically (e.g. via the DomContentLoaded event).</param>
+    /// <param name="browserSettings">browser settings, defaults to source browsers</param>
+    /// <returns>To cancel creation of the popup return true otherwise return false.</returns>
+    public delegate PopupCreation OnBeforePopupCreatedDelegate(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, string targetUrl, string targetFrameName, WindowOpenDisposition targetDisposition, bool userGesture, IBrowserSettings browserSettings);
+
     /// <summary>
     /// Called when the <see cref="ChromiumHostControl"/> has been created.
     /// When called you must add the control to it's intended parent
@@ -53,6 +72,7 @@ namespace CefSharp.WinForms.Handler
     public class LifeSpanHandler : CefSharp.Handler.LifeSpanHandler
     {
         private readonly Dictionary<int, ParentFormMessageInterceptor> popupParentFormMessageInterceptors = new Dictionary<int, ParentFormMessageInterceptor>();
+        private OnBeforePopupCreatedDelegate onBeforePopupCreated;
         private OnPopupDestroyedDelegate onPopupDestroyed;
         private OnPopupBrowserCreatedDelegate onPopupBrowserCreated;
         private OnPopupCreatedDelegate onPopupCreated;
@@ -159,8 +179,21 @@ protected override bool OnBeforePopup(IWebBrowser chromiumWebBrowser, IBrowser b
         {
             newBrowser = null;
 
+            PopupCreation userAction = onBeforePopupCreated?.Invoke(chromiumWebBrowser, browser, frame, targetUrl, targetFrameName, targetDisposition, userGesture, browserSettings) ?? PopupCreation.Continue;
+
+            //Cancel popup creation
+            if(userAction == PopupCreation.Cancel)
+            {
+                return true;
+            }
+
+            if(userAction == PopupCreation.ContinueWithJavascriptDisabled)
+            {
+                noJavascriptAccess = true;
+            }
+
             //No action so we'll go with the default behaviour.
-            if(onPopupCreated == null)
+            if (onPopupCreated == null)
             {
                 return false;
             }
@@ -204,13 +237,26 @@ protected override bool OnBeforePopup(IWebBrowser chromiumWebBrowser, IBrowser b
             return false;
         }
 
+        /// <summary>
+        /// The <see cref="OnBeforePopupCreatedDelegate"/> will be called <b>before</b> the popup has been created and
+        /// can be used to cancel popup creation if required or modify <see cref="IBrowserSettings"/>.
+        /// </summary>
+        /// <param name="onBeforePopupCreated">Action to be invoked before popup is created.</param>
+        /// <returns><see cref="LifeSpanHandler"/> instance allowing you to chain method calls together</returns>
+        public LifeSpanHandler OnBeforePopupCreated(OnBeforePopupCreatedDelegate onBeforePopupCreated)
+        {
+            this.onBeforePopupCreated = onBeforePopupCreated;
+
+            return this;
+        }
+
         /// <summary>
         /// The <see cref="OnPopupCreatedDelegate"/> will be called when the<see cref="ChromiumHostControl"/> has been
         /// created. When the <see cref="OnPopupCreatedDelegate"/> is called you must add the control to it's intended parent
         /// so the <see cref="Control.ClientRectangle"/> can be calculated to set the initial
         /// size correctly.
         /// </summary>
-        /// <param name="onPopupCreated">Action to be invoked when the Popup host has been created and is ready to be attached to it's parent..</param>
+        /// <param name="onPopupCreated">Action to be invoked when the Popup host has been created and is ready to be attached to it's parent.</param>
         /// <returns><see cref="LifeSpanHandler"/> instance allowing you to chain method calls together</returns>
         public LifeSpanHandler OnPopupCreated(OnPopupCreatedDelegate onPopupCreated)
         {

CefSharp.WinForms/Handler/LifeSpanHandlerBuilder.cs

@@ -16,14 +16,27 @@ public LifeSpanHandlerBuilder(CreatePopupChromiumHostControl chromiumHostControl
             handler = new LifeSpanHandler(chromiumHostControlCreatedDelegate);
         }
 
+        /// <summary>
+        /// The <see cref="OnBeforePopupCreatedDelegate"/> will be called <b>before</b> the popup has been created and
+        /// can be used to cancel popup creation if required, modify <see cref="IBrowserSettings"/> and disable javascript.
+        /// </summary>
+        /// <param name="onBeforePopupCreated">Action to be invoked before popup is created.</param>
+        /// <returns><see cref="LifeSpanHandlerBuilder"/> instance allowing you to chain method calls together</returns>
+        public LifeSpanHandlerBuilder OnBeforePopupCreated(OnBeforePopupCreatedDelegate onBeforePopupCreated)
+        {
+            handler.OnBeforePopupCreated(onBeforePopupCreated);
+
+            return this;
+        }
+
         /// <summary>
         /// The <see cref="OnPopupCreatedDelegate"/> will be called when the<see cref="ChromiumHostControl"/> has been
         /// created. When the <see cref="OnPopupCreatedDelegate"/> is called you must add the control to it's intended parent
         /// so the <see cref="Control.ClientRectangle"/> can be calculated to set the initial
         /// size correctly.
         /// </summary>
         /// <param name="onPopupCreated">Action to be invoked when the Popup is to be destroyed.</param>
-        /// <returns><see cref="LifeSpanHandler"/> instance allowing you to chain method calls together</returns>
+        /// <returns><see cref="LifeSpanHandlerBuilder"/> instance allowing you to chain method calls together</returns>
         public LifeSpanHandlerBuilder OnPopupCreated(OnPopupCreatedDelegate onPopupCreated)
         {
             handler.OnPopupCreated(onPopupCreated);
@@ -38,7 +51,7 @@ public LifeSpanHandlerBuilder OnPopupCreated(OnPopupCreatedDelegate onPopupCreat
         /// perform navigation (via frame) etc.
         /// </summary>
         /// <param name="onPopupBrowserCreated">Action to be invoked when the <see cref="IBrowser"/> has been created.</param>
-        /// <returns><see cref="LifeSpanHandler"/> instance allowing you to chain method calls together</returns>
+        /// <returns><see cref="LifeSpanHandlerBuilder"/> instance allowing you to chain method calls together</returns>
         public LifeSpanHandlerBuilder OnPopupBrowserCreated(OnPopupBrowserCreatedDelegate onPopupBrowserCreated)
         {
             handler.OnPopupBrowserCreated(onPopupBrowserCreated);
@@ -52,7 +65,7 @@ public LifeSpanHandlerBuilder OnPopupBrowserCreated(OnPopupBrowserCreatedDelegat
         /// When the <see cref="OnPopupDestroyedDelegate"/> is called you must remove/dispose of the <see cref="ChromiumHostControl"/>.
         /// </summary>
         /// <param name="onPopupDestroyed">Action to be invoked when the Popup is to be destroyed.</param>
-        /// <returns><see cref="LifeSpanHandler"/> instance allowing you to chain method calls together</returns>
+        /// <returns><see cref="LifeSpanHandlerBuilder"/> instance allowing you to chain method calls together</returns>
         public LifeSpanHandlerBuilder OnPopupDestroyed(OnPopupDestroyedDelegate onPopupDestroyed)
         {
             handler.OnPopupDestroyed(onPopupDestroyed);

CefSharp.WinForms/Handler/PopupCreation.cs

@@ -0,0 +1,25 @@
+// Copyright © 2022 The CefSharp Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+namespace CefSharp.WinForms.Handler
+{
+    /// <summary>
+    /// Popup Creation options
+    /// </summary>
+    public enum PopupCreation
+    {
+        /// <summary>
+        /// Popup creation is cancled, no further action will occur
+        /// </summary>
+        Cancel = 0,
+        /// <summary>
+        /// Popup creation will continue as per normal.
+        /// </summary>
+        Continue,
+        /// <summary>
+        /// Popup creation will continue with javascript disabled.
+        /// </summary>
+        ContinueWithJavascriptDisabled
+    }
+}