C# 通过扩展WebBrowser捕获网络连接错误信息

想捕获WebBrowser连接指定网站过程中发生的错误信息，包括网络无法连接、404找不到网页等等错误！经过网上的搜集，找到了以下解决方案，该解决方案不会在网站连接前发出多余的测试请求。

向Webbrowser中注册NavigateError事件，以扩展webbrowser：

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

InterfaceType(ComInterfaceType.InterfaceIsIDispatch),

TypeLibType(TypeLibTypeFlags.FHidden)]

public interface DWebBrowserEvents2

{

    [DispId(271)]

    void NavigateError(

        [In, MarshalAs(UnmanagedType.IDispatch)] object pDisp,

        [In] ref object URL, [In] ref object frame,

        [In] ref object statusCode, [In, Out] ref bool cancel);

}

 

自定义NavigateError事件的参数：

using System;

using System.Runtime.InteropServices;

public class WebBrowserNavigateErrorEventArgs : EventArgs

{

    private String urlValue;

    private String frameValue;

    private Int32 statusCodeValue;

    private Boolean cancelValue;

    public WebBrowserNavigateErrorEventArgs(

        String url, String frame, Int32 statusCode, Boolean cancel)

    {

        urlValue = url;

        frameValue = frame;

        statusCodeValue = statusCode;

        cancelValue = cancel;

    }

    public String Url

    {

        get { return urlValue; }

        set { urlValue = value; }

    }

    public String Frame

    {

        get { return frameValue; }

        set { frameValue = value; }

    }

    public Int32 StatusCode

    {

        get { return statusCodeValue; }

        set { statusCodeValue = value; }

    }

    public Boolean Cancel

    {

        get { return cancelValue; }

        set { cancelValue = value; }

    }

}

 

 

扩展webbrowser为MyWebBrowser，在程序中将webbrowser改成Mywebbrowser即可：

using System.Windows.Forms;

using System.Security.Permissions;

using System.Runtime.InteropServices;

using System;

public class MyWebBrowser : WebBrowser

{

    AxHost.ConnectionPointCookie cookie;

    MyWebBrowserEventHelper helper;

    public delegate void WebBrowserNavigateErrorEventHandler(object sender,

        WebBrowserNavigateErrorEventArgs e);



    [PermissionSetAttribute(SecurityAction.LinkDemand, Name = "FullTrust")]

    protected override void CreateSink()

    {

        base.CreateSink();

        // Create an instance of the client that will handle the event

        // and associate it with the underlying ActiveX control.

        helper = new MyWebBrowserEventHelper(this);

        cookie = new AxHost.ConnectionPointCookie(

            this.ActiveXInstance, helper, typeof(DWebBrowserEvents2));

    }

    [PermissionSetAttribute(SecurityAction.LinkDemand, Name = "FullTrust")]

    protected override void DetachSink()

    {

        // Disconnect the client that handles the event

        // from the underlying ActiveX control.

        if (cookie != null)

        {

            cookie.Disconnect();

            cookie = null;

        }

        base.DetachSink();

    }

    public event WebBrowserNavigateErrorEventHandler NavigateError;

    // Raises the NavigateError event.

    protected virtual void OnNavigateError(

        WebBrowserNavigateErrorEventArgs e)

    {

        if (this.NavigateError != null)

        {

            this.NavigateError(this, e);

        }

    }

    // Handles the NavigateError event from the underlying ActiveX 

    // control by raising the NavigateError event defined in this class.

    private class MyWebBrowserEventHelper :

        StandardOleMarshalObject, DWebBrowserEvents2

    {

        private MyWebBrowser parent;

        public MyWebBrowserEventHelper(MyWebBrowser parent)

        {

            this.parent = parent;

        }

        public void NavigateError(object pDisp, ref object url,

            ref object frame, ref object statusCode, ref bool cancel)

        {

            // Raise the NavigateError event.

            this.parent.OnNavigateError(

                new WebBrowserNavigateErrorEventArgs(

                (String)url, (String)frame, (Int32)statusCode, cancel));

        }

    }

}

 

 

将以上代码完全复制粘贴到您的程序当中，然后将您原本程序中使用webbrowser的地方修改成MyWebBrowser就行了。这个时候你的mywebbrowser控件就有了onnavigateerror事件，在这个事件里编写您的错误处理方法。您或许需要用到错误消息中的错误代码，具体错误代码请参照里的每个错误代码代表的意义。

本人项目中所使用的错误处理代码如下：

 private void WebBrowserIE_NavigateError(object sender, WebBrowserNavigateErrorEventArgs e)

        {

            log.Debug("ERROR:----------" + e.Url);

            int code = e.StatusCode;

            // 发生错误时，转向本地页面

            if (code == -2146697211)

            {                WebBrowserIE.Navigate("本地页面");

            }

        }

 

这个扩展方法完全不会影响webbrowser原有的任何功能，当然，您还可以按照这种思路继续进行扩展，比如扩展使其用有mousemove事件，也是可以的！