在发布“淘宝登货员”时发现不少朋友对WebBrowser控件比较感兴趣，故在此分享一下使用心得。

首先分享一个WebBrowser的扩展类（此类所需的dll将在文章末尾提供下载），大家最好都使用这个类来替代.Net框架中的WebBrowser类，它提供了两个扩展功能：

1.屏蔽错误脚本提示。修正了WebBrowser控件本身屏蔽错误不全的问题，由启明提出，原文：http://www.cnblogs.com/hobe/archive/2007/01/14/619906.html

2.扩展NewWindow事件。修正了WebBrowser控件本身的NewWindow事件不提供新窗口Url的问题，通过新增的BeforeNewWindow事件予以支持，由佳文转载并整理，原文：http://www.cnblogs.com/yjwgood/archive/2009/02/09/1386789.html

整合后的代码如下：

public class ExWebBrowser : System.Windows.Forms.WebBrowser

{

private SHDocVw.IWebBrowser2 Iwb2;

protected override void AttachInterfaces(object nativeActiveXObject)

{

Iwb2 = (SHDocVw.IWebBrowser2)nativeActiveXObject;

Iwb2.Silent = true;

base.AttachInterfaces(nativeActiveXObject);

}

protected override void DetachInterfaces()

{

Iwb2 = null;

base.DetachInterfaces();

}

System.Windows.Forms.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 System.Windows.Forms.AxHost.ConnectionPointCookie(this.ActiveXInstance, events, typeof(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 BeforeNavigate;

/// <summary>

/// 可用于替代原来的NewWindow事件，新增了事件的Url参数支持。

/// </summary>

[CategoryAttribute("操作"), DescriptionAttribute("经过扩展的NewWindow事件，使用继承后的WebBrowserExtendedNavigatingEventArgs类型参数实现Url参数支持")]

public event EventHandler BeforeNewWindow;

protected void OnBeforeNewWindow(string url, out bool cancel)

{

EventHandler h = BeforeNewWindow;

WebBrowserExtendedNavigatingEventArgs args = new WebBrowserExtendedNavigatingEventArgs(url, null);

if (null != h)

{

h(this, args);

}

cancel = args.Cancel;

}

protected void OnBeforeNavigate(string url, string frame, out bool cancel)

{

EventHandler h = BeforeNavigate;

WebBrowserExtendedNavigatingEventArgs args = new WebBrowserExtendedNavigatingEventArgs(url, frame);

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, DWebBrowserEvents2

{

ExWebBrowser _Browser;

public WebBrowserExtendedEvents(ExWebBrowser 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.OnBeforeNavigate((string)URL, (string)targetFrameName, out cancel);

}

public void NewWindow3(object pDisp, ref bool cancel, ref object flags, ref object URLContext, ref object URL)

{

_Browser.OnBeforeNewWindow((string)URL, out cancel);

}

[System.Runtime.InteropServices.ComImport(), System.Runtime.InteropServices.Guid("34A715A0-6587-11D0-924A-0020AFC7AC4D"),

System.Runtime.InteropServices.InterfaceTypeAttribute(System.Runtime.InteropServices.ComInterfaceType.InterfaceIsIDispatch),

System.Runtime.InteropServices.TypeLibType(System.Runtime.InteropServices.TypeLibTypeFlags.FHidden)]

public interface DWebBrowserEvents2

{

[System.Runtime.InteropServices.DispId(250)]

void BeforeNavigate2(

[System.Runtime.InteropServices.In,

System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.IDispatch)] object pDisp,

[System.Runtime.InteropServices.In] ref object URL,

[System.Runtime.InteropServices.In] ref object flags,

[System.Runtime.InteropServices.In] ref object targetFrameName, [System.Runtime.InteropServices.In] ref object postData,

[System.Runtime.InteropServices.In] ref object headers,

[System.Runtime.InteropServices.In,

System.Runtime.InteropServices.Out] ref bool cancel);

[System.Runtime.InteropServices.DispId(273)]

void NewWindow3(

[System.Runtime.InteropServices.In,

System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.IDispatch)] object pDisp,

[System.Runtime.InteropServices.In, System.Runtime.InteropServices.Out] ref bool cancel,

[System.Runtime.InteropServices.In] ref object flags,

[System.Runtime.InteropServices.In] ref object URLContext,

[System.Runtime.InteropServices.In] ref object URL);

}

public class WebBrowserExtendedNavigatingEventArgs : CancelEventArgs

{

private string _Url;

public string Url

{

get { return _Url; }

}

private string _Frame;

public string Frame

{

get { return _Frame; }

}

public WebBrowserExtendedNavigatingEventArgs(string url, string frame)

: base()

{

_Url = url;

_Frame = frame;

}

技巧1：在当前窗口内打开目标为新窗口的超链接

通过上述的扩展类支持得以实现，增加BeforeNewWindow事件的处理函数以进行处理：

void webBrowser1_BeforeNewWindow(object sender, EventArgs e)

{

WebBrowserExtendedNavigatingEventArgs eventArgs = e as WebBrowserExtendedNavigatingEventArgs;

if (eventArgs.Url.ToLower() != "about:blank")

webBrowser1.Navigate(eventArgs.Url);

eventArgs.Cancel = true;

}

这种方法的弊病在于可能会错误地转向到网站的弹窗广告，为了规避此问题，可以强制取消一切弹出窗口，采取另一种方法实现当前窗口内打开新窗口超链接，增加DocumentCompleted事件的处理函数以进行处理：

void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)

{

if (webBrowser1.ReadyState > WebBrowserReadyState.Interactive)

{

foreach (HtmlElement f in webBrowser1.Document.Links)

{

var s = f.GetAttribute("target");

if (s != null && s.ToLower() == "_blank") f.SetAttribute("target", "_self");

}

此方法将遍历所有<a>元素，修改其目标为当前窗口，但是此方法又会引发新的问题，即如果页面中某些元素长时间都未加载完成时，此事件将迟迟不会被引发，也就是说用户必须要等到页面完完全全加载完毕之后才可能在当前窗口内打开新窗口超链接。

根据一些人的经验，DocumentCompleted事件会在每次加载网页的过程中触发两次，第一次触发时WebBrowser控件的ReadyState属性应为Interactive，第二次则为Complete，根据注释来看，Interactive应该是代表页面加载初步完成，已具有基本交互能力的状态，这时应当是理想的编辑状态，但我尝试将代码中的if (webBrowser1.ReadyState > WebBrowserReadyState.Interactive)修改为if(webBrowser1.ReadyState >= WebBrowserReadyState.Interactive)，并没有什么明显效果，页面上的超链接还是要等待全部加载之后才会被修改。