WinForms - ChromiumHostControl add BrowserCore and IsBrowserInitialized event

- Can now access the IBrowser property via ChromiumHostControl.BrowserCore
- The ChromiumHostControl.IsBrowserInitialized event will be raised when
the underlying CEF browser has been created.

Author: amaitland

CefSharp.WinForms.Example/BrowserTabUserControl.cs

@@ -91,8 +91,14 @@ public BrowserTabUserControl(Action<string, int?> openNewTab, string url, bool m
                         }
                     }
                 })
-                .OnPopupBrowserCreated((popupBrowser) =>
+                .OnPopupBrowserCreated((ctrl, popupBrowser) =>
                 {
+                    //The host control maybe null if the popup was hosted in a native Window e.g. Devtools by default
+                    if(ctrl == null)
+                    {
+                        return;
+                    }
+
                     //You can access all the core browser functionality via IBrowser
                     //frames, browwser host, etc.
                     var isPopup = popupBrowser.IsPopup;

CefSharp.WinForms/ChromiumWebBrowser.cs

@@ -198,13 +198,6 @@ public IRequestContext RequestContext
         /// To access UI elements you'll need to Invoke/Dispatch onto the UI Thread.
         /// </summary>
         public event EventHandler<TitleChangedEventArgs> TitleChanged;
-        /// <summary>
-        /// Event called after the underlying CEF browser instance has been created. 
-        /// It's important to note this event is fired on a CEF UI thread, which by default is not the same as your application UI
-        /// thread. It is unwise to block on this thread for any length of time as your browser will become unresponsive and/or hang..
-        /// To access UI elements you'll need to Invoke/Dispatch onto the UI Thread.
-        /// </summary>
-        public event EventHandler IsBrowserInitializedChanged;
 
         /// <summary>
         /// A flag that indicates whether the state of the control currently supports the GoForward action (true) or not (false).
@@ -398,7 +391,6 @@ private void InternalDispose(bool disposing)
                 ConsoleMessage = null;
                 FrameLoadEnd = null;
                 FrameLoadStart = null;
-                IsBrowserInitializedChanged = null;
                 LoadError = null;
                 LoadingStateChanged = null;
                 StatusMessage = null;
@@ -604,6 +596,7 @@ private void CreateBrowser()
         /// <param name="browser">The browser.</param>
         partial void OnAfterBrowserCreated(IBrowser browser)
         {
+            BrowserCore = browser;
             BrowserHwnd = browser.GetHost().GetWindowHandle();
 
             // By the time this callback gets called, this control
@@ -639,7 +632,7 @@ partial void OnAfterBrowserCreated(IBrowser browser)
                 browser.GetHost()?.SetFocus(true);
             }
 
-            IsBrowserInitializedChanged?.Invoke(this, EventArgs.Empty);
+            RaiseIsBrowserInitializedChangedEvent();
         }
 
         /// <summary>
@@ -769,7 +762,7 @@ protected override void OnGotFocus(EventArgs e)
         /// <summary>
         /// Returns the current IBrowser Instance
         /// </summary>
-        /// <returns>browser instance or null</returns>
+        /// <returns>browser instance</returns>
         public IBrowser GetBrowser()
         {
             ThrowExceptionIfDisposed();

CefSharp.WinForms/Handler/LifeSpanHandler.cs

@@ -24,8 +24,10 @@ namespace CefSharp.WinForms.Handler
     /// Called when the <see cref="IBrowser"/> instance has been created.
     /// The <see cref="IBrowser"/> reference will be valid until <see cref="OnPopupDestroyedDelegate"/> is called
     /// </summary>
+    /// <param name="control">popup host control, maybe null if Browser is hosted in a native Popup window.
+    /// DevTools by default will be hosted in a native popup window.</param>
     /// <param name="browser">browser</param>
-    public delegate void OnPopupBrowserCreatedDelegate(IBrowser browser);
+    public delegate void OnPopupBrowserCreatedDelegate(ChromiumHostControl control, IBrowser browser);
 
     /// <summary>
     /// Called when the <see cref="ChromiumHostControl"/> is to be removed from it's parent.
@@ -53,8 +55,7 @@ protected override bool DoClose(IWebBrowser chromiumWebBrowser, IBrowser browser
         {
             if (browser.IsPopup)
             {
-                var windowHandle = browser.GetHost().GetWindowHandle();
-                var control = Control.FromChildHandle(windowHandle) as ChromiumHostControl;
+                var control = ChromiumHostControl.FromBrowser(browser);
 
                 //We don't have a parent control so we allow the default behaviour, required to close
                 //default popups e.g. DevTools
@@ -86,21 +87,17 @@ protected override void OnAfterCreated(IWebBrowser chromiumWebBrowser, IBrowser
         {
             if (browser.IsPopup)
             {
-                onPopupBrowserCreated?.Invoke(browser);
-
-                var windowHandle = browser.GetHost().GetWindowHandle();
-
                 //WinForms will kindly lookup the child control from it's handle
                 //If no parentControl then likely it's a native popup created by CEF
                 //(Devtools by default will open as a popup, at this point the Url hasn't been set, so 
                 // we're going with this assumption as it fits the use case currently)
-                var control = Control.FromChildHandle(windowHandle) as ChromiumHostControl;
+                var control = ChromiumHostControl.FromBrowser(browser);
 
                 //If control is null then we'll treat as a native popup (do nothing)
                 //If control is disposed there's nothing for us to do either.
                 if (control != null && !control.IsDisposed)
                 {
-                    control.BrowserHwnd = windowHandle;
+                    control.BrowserHwnd = browser.GetHost().GetWindowHandle();
 
                     control.InvokeOnUiThreadIfRequired(() =>
                     {
@@ -114,8 +111,13 @@ protected override void OnAfterCreated(IWebBrowser chromiumWebBrowser, IBrowser
                         };
 
                         popupParentFormMessageInterceptors.Add(browser.Identifier, interceptor);
-                    });                   
+                    });
+
+                    control.BrowserCore = browser;
+                    control.RaiseIsBrowserInitializedChangedEvent();
                 }
+
+                onPopupBrowserCreated?.Invoke(control, browser);
             }
         }
 

CefSharp.WinForms/Host/ChromiumHostControl.cs

@@ -19,6 +19,12 @@ namespace CefSharp.WinForms.Host
     Designer(typeof(ChromiumWebBrowserDesigner))]
     public class ChromiumHostControl : Control
     {
+        /// <summary>
+        /// Get access to the core <see cref="IBrowser"/> instance.
+        /// Maybe null if the underlying CEF Browser has not yet been
+        /// created or if this control has been disposed.
+        /// </summary>
+        public IBrowser BrowserCore { get; internal set; }
         /// <summary>
         /// IntPtr that represents the CefBrowser Hwnd
         /// Used for sending messages to the browser
@@ -33,6 +39,14 @@ public class ChromiumHostControl : Control
         [Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden), DefaultValue(false)]
         public bool IsActivating { get; set; }
 
+        /// <summary>
+        /// Event called after the underlying CEF browser instance has been created. 
+        /// It's important to note this event is fired on a CEF UI thread, which by default is not the same as your application UI
+        /// thread. It is unwise to block on this thread for any length of time as your browser will become unresponsive and/or hang..
+        /// To access UI elements you'll need to Invoke/Dispatch onto the UI Thread.
+        /// </summary>
+        public event EventHandler IsBrowserInitializedChanged;
+
         /// <summary>
         /// Gets the default size of the control.
         /// </summary>
@@ -161,10 +175,45 @@ protected override void Dispose(bool disposing)
         {
             if (disposing)
             {
+                BrowserCore = null;
                 BrowserHwnd = IntPtr.Zero;
+                IsBrowserInitializedChanged = null;
             }
 
             base.Dispose(disposing);
         }
+
+        /// <summary>
+        /// Trigger the <see cref="IsBrowserInitializedChanged"/> event
+        /// </summary>
+        internal void RaiseIsBrowserInitializedChangedEvent()
+        {
+            IsBrowserInitializedChanged?.Invoke(this, EventArgs.Empty);
+        }
+
+        /// <summary>
+        /// Gets the <see cref="ChromiumHostControl"/> associated with
+        /// a specific <see cref="IBrowser"/> instance. 
+        /// </summary>
+        /// <param name="browser">browser</param>
+        /// <returns>returns the assocaited <see cref="ChromiumHostControl"/> or null if Disposed or no host found.</returns>
+        public static ChromiumHostControl FromBrowser(IBrowser browser)
+        {
+            if(browser.IsDisposed)
+            {
+                return null;
+            }
+
+            var windowHandle = browser.GetHost().GetWindowHandle();
+
+            if(windowHandle == IntPtr.Zero)
+            {
+                return null;
+            }
+
+            var control = Control.FromChildHandle(windowHandle) as ChromiumHostControl;
+
+            return control;
+        }
     }
 }