PCB Winform中的WebBrowser扩展拖放(拖拽)功能 实现方法

我们在Winform支持网页通常增加WebBrowser控件实现，相当于内嵌浏览器浏览网页使用，

而此WebBrowser默认情况是文件拖入功能是不支持的，

如何才能支持呢。在这里介绍如何实现方法

一.直接上源码吧，

       下载后直接用，其实不要了解太深入，会用就行了啦（用之前，网页需有加入JS drop功能）

      下载地址   http://pcbren.cn/ShareFiles/WebbrowserDemoDrop.zip

二.实现拖拽是重构WebBrowser浏览器Drag事件，让浏览器支持拖拽功能，以下为部份代码：

    public partial class ExtendedWebBrowser : System.Windows.Forms.WebBrowser, MsHtmHstInterop.IDocHostUIHandler, MsHtmHstInterop.IDropTarget, IEInterface.IWebBrowser2
    {
        
        public event Events.DragEnterEventHander ExDragEnter;
        private Events.DragEnterEventArgs dragEnterEventArgs;
        public event Events.DragOverEventHander ExDragOver;
        private Events.DragOverEventArgs dragOverEventArgs;
        public event Events.DragLeaveEventHander ExDragLeave;
        public event Events.DragDropEventHander ExDragDrop;
        private Events.DragDropEventArgs dragDropEventArgs;
        private bool registerAsDropTarget = true;
        private bool registerAsBrowser = true;
        private bool slient = true;
        MsHtmHstInterop.IDropTarget pDropTarget;//保存原有的拖放对象
        private bool isDragToInputBox = false;//判断是否是在向输入框中拖放

        public ExtendedWebBrowser()
        {
            InitializeComponent();
            this.AllowWebBrowserDrop = true;
            Navigate("about:blank");
            MsHtmHstInterop.ICustomDoc idoc = this.Document.DomDocument as MsHtmHstInterop.ICustomDoc;
            idoc.SetUIHandler(this as MsHtmHstInterop.IDocHostUIHandler);
            dragEnterEventArgs = new Events.DragEnterEventArgs();
            dragOverEventArgs = new Events.DragOverEventArgs();
            dragDropEventArgs = new Events.DragDropEventArgs();
        }



        #region 获取新窗口Url
        AxHost.ConnectionPointCookie cookie;
        WebBrowserExtendedEvents events;

        //This method will be called to give you a chance to create your own event sink
        protected override void CreateSink()
        {
            //MAKE SURE TO CALL THE BASE or the normal events won't fire
            base.CreateSink();
            events = new WebBrowserExtendedEvents(this);
            cookie = new AxHost.ConnectionPointCookie(this.ActiveXInstance, events, typeof(LuckyPang.ControlLibrary.IEInterface.DWebBrowserEvents2));
        }

        protected override void DetachSink()
        {
            if (null != cookie)
            {
                cookie.Disconnect();
                cookie = null;
            }
            base.DetachSink();
        }

        //This new event will fire when the page is navigating
        public event EventHandler<WebBrowserExtendedNavigatingEventArgs> ExtendedNavigating;

        protected void OnExtendedNavigating(string url, string frame, out bool cancel)
        {
            EventHandler<WebBrowserExtendedNavigatingEventArgs> h = ExtendedNavigating;
            WebBrowserExtendedNavigatingEventArgs args = new WebBrowserExtendedNavigatingEventArgs(url, frame);
            if (null != h)
            {
                h(this, args);
            }
            //Pass the cancellation chosen back out to the events
            cancel = args.Cancel;
        }

        public event EventHandler<WebBrowserExtendedNewWindowEventArgs> ExtendedNewWindow;

        protected void OnExtendedNewWindow(string url,out bool cancel)
        {
            EventHandler<WebBrowserExtendedNewWindowEventArgs> h = ExtendedNewWindow;
            WebBrowserExtendedNewWindowEventArgs args = new WebBrowserExtendedNewWindowEventArgs(url);
            if (null != h)
            {
                h(this, args);
            }
            //Pass the cancellation chosen back out to the events
            cancel = args.Cancel;
        }

        public event EventHandler<Events.WebBrowserExtendedWindowClosingEventArgs> ExtendedWindowClosing;
        protected void OnExtendWindowClosing(out bool cancel)
        {
            EventHandler<Events.WebBrowserExtendedWindowClosingEventArgs> h = ExtendedWindowClosing;
            Events.WebBrowserExtendedWindowClosingEventArgs args = new Events.WebBrowserExtendedWindowClosingEventArgs();
            if (null != h)
            {
                h(this, args);
            }
            //Pass the cancellation chosen back out to the events
            cancel = args.Cancel;
        }

        //This class will capture events from the WebBrowser
        class WebBrowserExtendedEvents : System.Runtime.InteropServices.StandardOleMarshalObject, LuckyPang.ControlLibrary.IEInterface.DWebBrowserEvents2
        {
            ExtendedWebBrowser _Browser;
            private bool m_bPop;
            public WebBrowserExtendedEvents(ExtendedWebBrowser browser)
            { _Browser = browser; }

            //Implement whichever events you wish
            public void BeforeNavigate2(object pDisp, ref object URL, ref object flags, ref object targetFrameName, ref object postData, ref object headers, ref bool cancel)
            {
                _Browser.OnExtendedNavigating((string)URL, (string)targetFrameName, out cancel);
            }

            public void NewWindow3(ref object ppDisp, ref bool Cancel, uint dwFlags, string bstrUrlContext, string bstrUrl)
            {
                _Browser.OnExtendedNewWindow(bstrUrl, out Cancel);
            }

            #region DWebBrowserEvents2 成员

            public void StatusTextChange(string Text)
            {
                throw new NotImplementedException();
            }

            public void ProgressChange(int Progress, int ProgressMax)
            {
                throw new NotImplementedException();
            }

            public void CommandStateChange(int Command, bool Enable)
            {
                throw new NotImplementedException();
            }

            public void DownloadBegin()
            {
                m_bPop = false;
            }

            public void DownloadComplete()
            {
                m_bPop = true;
            }

            public void TitleChange(string Text)
            {
                throw new NotImplementedException();
            }

            public void PropertyChange(string szProperty)
            {
                throw new NotImplementedException();
            }

            public void NewWindow2(ref object ppDisp, ref bool Cancel)
            {
                Cancel = m_bPop;
            }

            public void NavigateComplete2(object pDisp, ref object URL)
            {
                throw new NotImplementedException();
            }

            public void DocumentComplete(object pDisp, ref object URL)
            {
                throw new NotImplementedException();
            }

            public void OnQuit()
            {
                throw new NotImplementedException();
            }

            public void OnVisible(bool Visible)
            {
                throw new NotImplementedException();
            }

            public void OnToolBar(bool ToolBar)
            {
                throw new NotImplementedException();
            }

            public void OnMenuBar(bool MenuBar)
            {
                throw new NotImplementedException();
            }

            public void OnStatusBar(bool StatusBar)
            {
                throw new NotImplementedException();
            }

            public void OnFullScreen(bool FullScreen)
            {
                throw new NotImplementedException();
            }

            public void OnTheaterMode(bool TheaterMode)
            {
                throw new NotImplementedException();
            }

            public void WindowSetResizable(bool Resizable)
            {
                throw new NotImplementedException();
            }

            public void WindowSetLeft(int Left)
            {
                throw new NotImplementedException();
            }

            public void WindowSetTop(int Top)
            {
                throw new NotImplementedException();
            }

            public void WindowSetWidth(int Width)
            {
                throw new NotImplementedException();
            }

            public void WindowSetHeight(int Height)
            {
                throw new NotImplementedException();
            }

            public void WindowClosing(bool IsChildWindow, ref bool Cancel)
            {
                _Browser.OnExtendWindowClosing(out Cancel);
            }

            public void ClientToHostWindow(ref int CX, ref int CY)
            {
                throw new NotImplementedException();
            }

            public void SetSecureLockIcon(int SecureLockIcon)
            {
                throw new NotImplementedException();
            }

            public void FileDownload(ref bool Cancel)
            {
                throw new NotImplementedException();
            }

            public void NavigateError(object pDisp, ref object URL, ref object Frame, ref object StatusCode, ref bool Cancel)
            {
                throw new NotImplementedException();
            }

            public void PrintTemplateInstantiation(object pDisp)
            {
                throw new NotImplementedException();
            }

            public void PrintTemplateTeardown(object pDisp)
            {
                throw new NotImplementedException();
            }

            public void UpdatePageStatus(object pDisp, ref object nPage, ref object fDone)
            {
                throw new NotImplementedException();
            }

            public void PrivacyImpactedStateChange(bool bImpacted)
            {
                throw new NotImplementedException();
            }

            #endregion
        }
        #endregion

        #region IDocHostUIHandler 成员

        void MsHtmHstInterop.IDocHostUIHandler.EnableModeless(int fEnable)
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.FilterDataObject(MsHtmHstInterop.IDataObject pDO, out MsHtmHstInterop.IDataObject ppDORet)
        {
            ppDORet = pDO;
        }

        void MsHtmHstInterop.IDocHostUIHandler.GetDropTarget(MsHtmHstInterop.IDropTarget pDropTarget, out MsHtmHstInterop.IDropTarget ppDropTarget)
        {
            this.pDropTarget = pDropTarget;//保存默认的对象
            ppDropTarget = this as MsHtmHstInterop.IDropTarget ;//把当前对角注册为拖放对象
        }

        void MsHtmHstInterop.IDocHostUIHandler.GetExternal(out object ppDispatch)
        {
            if (this.ObjectForScripting != null)
            {
                ppDispatch = this.ObjectForScripting;
            }
            else
            {
                ppDispatch = null;
            }
        }

        void MsHtmHstInterop.IDocHostUIHandler.GetHostInfo(ref MsHtmHstInterop._DOCHOSTUIINFO pInfo)
        {
            pInfo.dwFlags = 0x00040000;
        }

        void MsHtmHstInterop.IDocHostUIHandler.GetOptionKeyPath(out string pchKey, uint dw)
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.HideUI()
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.OnDocWindowActivate(int fActivate)
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.OnFrameWindowActivate(int fActivate)
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.ResizeBorder(ref MsHtmHstInterop.tagRECT prcBorder, MsHtmHstInterop.IOleInPlaceUIWindow pUIWindow, int fRameWindow)
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.ShowContextMenu(uint dwID, ref MsHtmHstInterop.tagPOINT ppt, object pcmdtReserved, object pdispReserved)
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.ShowUI(uint dwID, MsHtmHstInterop.IOleInPlaceActiveObject pActiveObject, MsHtmHstInterop.IOleCommandTarget pCommandTarget, MsHtmHstInterop.IOleInPlaceFrame pFrame, MsHtmHstInterop.IOleInPlaceUIWindow pDoc)
        {
            if (pActiveObject != null)
            {
                pActiveObject.GetWindow((IntPtr )0);
            }
        }

        void MsHtmHstInterop.IDocHostUIHandler.TranslateAccelerator(ref MsHtmHstInterop.tagMSG lpmsg, ref Guid pguidCmdGroup, uint nCmdID)
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.TranslateUrl(uint dwTranslate, ref ushort pchURLIn, IntPtr ppchURLOut)
        {
            throw new NotImplementedException();
        }

        void MsHtmHstInterop.IDocHostUIHandler.UpdateUI()
        {
            throw new NotImplementedException();
        }

        #endregion

        #region IDropTarget 成员

        public new void DragEnter(MsHtmHstInterop.IDataObject pDataObj, uint grfKeyState, MsHtmHstInterop._POINTL pt, ref uint pdwEffect)
        {
            pDropTarget.DragEnter(pDataObj, grfKeyState, pt, ref pdwEffect);//调用默认方法
            //获取拖动的参数
            if (ExDragEnter != null)
            {
                DataObject dobj = null;
                if (pDataObj != null)
                {
                    dobj = new DataObject(pDataObj);//拖动数据
                    Point p = new Point(pt.x, pt.y);//鼠标在容器上的位置
                    dragEnterEventArgs.SetParameters(dobj, grfKeyState, p, pdwEffect);
                    ExDragEnter(this, dragEnterEventArgs);//此处为自定义事件
                    if (dragEnterEventArgs.handled)//自定义事件的返回值
                    {
                        pdwEffect = dragEnterEventArgs.pdwEffect;
                    }
                }
            }
        }

        public new void DragLeave()
        {
            pDropTarget.DragLeave();//调用默认的方法
            if (ExDragLeave != null)
            {
                ExDragLeave(this);//自定义事件
            }
        }

        public new void DragOver(uint grfKeyState, MsHtmHstInterop._POINTL pt, ref uint pdwEffect)
        {
            uint temp = pdwEffect;//保存原有的拖放效果,当调用默认的
                                  //操作时此参数会改变,并根据此来判
                                  //断是否向输入框中拖放

            pDropTarget.DragOver(grfKeyState, pt, ref pdwEffect);//调用默认方法        
            if (pdwEffect > 0)//如果值变为了零,那么是向输入框中拖放了
            {
                isDragToInputBox = true;//标记设为true
                temp = 0;
            }
            else
            {
                isDragToInputBox = false;//否则标记设为false
                pdwEffect = temp;
            }
            if (ExDragOver != null)//自定义事件处理
            {
                Point p = new Point(pt.x, pt.y);
                dragOverEventArgs.SetParameters(grfKeyState, p, temp);
                if (dragOverEventArgs.handled)
                {
                    pdwEffect = dragOverEventArgs.pdwEffect;
                }
            }
        }

        public void Drop(MsHtmHstInterop.IDataObject pDataObj, uint grfKeyState, MsHtmHstInterop._POINTL pt, ref uint pdwEffect)
        {
            if (ExDragDrop != null)//自定义事件处理
            {
                if (pDataObj != null && !isDragToInputBox )//如果没有向输入框中拖放则触发此事件
                                                           //否则按默认处理
                {
                    DataObject dobj = new DataObject(pDataObj);
                    Point p = new Point(pt.x, pt.y);
                    dragDropEventArgs.SetParameters(dobj, grfKeyState, p, pdwEffect);
                    ExDragDrop(this, dragDropEventArgs);
                    if (dragDropEventArgs.handled)
                    {
                        pdwEffect = dragDropEventArgs.pdwEffect;
                    }
                }
            }
            pDropTarget.Drop(pDataObj, grfKeyState, pt, ref pdwEffect);//调用默认方法
        }

        #endregion

        #region IWebBrowser2 成员

        public bool RegisterAsDropTarget
        {
            get
            {
                return registerAsDropTarget;
            }
            set
            {
                registerAsDropTarget = value;
            }
        }
        public bool Silent
        {
            get
            {
                return slient;
            }
            set
            {
                slient = value;
            }
        }

        public bool RegisterAsBrowser 
        { 
            get
            {
                return registerAsBrowser; 
            }
            set
            {
                registerAsBrowser = value;
            }
        }
        #endregion
    }

三.拖拽界面展示：