kevin8977

2009-09-01

讓WebBrowser可以辨認Navigate Error Http 404 的錯誤(不止404)

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webbrowser控制項，傳回NavigateError事件

 

WebBrowserExtensibility.rar為了要讓WEBBROWSER能夠追到網頁的ERROR CODE查了好多資料，都沒結果，好不容易找到了MSDN，卻還是看不懂，不過MSDN的好處是稍稍理解一下，就可以直接剪程式碼來用了，我把程式碼做作CLASS，只要讓WEBBROWSER實做WEBBROWSER2即可。(也是要稍稍動點手腳啦)

在Form1.designer.cs裡面要改成

this.xwebbowser = new  WebBrowser2();

然後手動寫事件發生時要做什麼

private void wb_NavigateError(object sender, WebBrowserNavigateErrorEventArgs e)
        {
console.writeline(e.StatusCode);
                    }

這裡要注意的是事件的委派要從『屬性』視窗的『事件』頁面的"其他"裡指定事件

這樣e.StatusCode就能帶出錯誤碼,EX:找不到頁面的http 404的那個404碼

msdn裡有列錯誤碼所代表的意思

http://msdn.microsoft.com/en-us/library/bb268233(VS.85).aspx


CLASS 如下

using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Security.Permissions;

namespace webHeartBeat_checker
{
    //繼承webbrowser
    public class WebBrowser2 : WebBrowser
    {
        AxHost.ConnectionPointCookie cookie;
        WebBrowser2EventHelper helper;

        [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 WebBrowser2EventHelper(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();
        }

        //加入一個新的事件
        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 WebBrowser2EventHelper : StandardOleMarshalObject, DWebBrowserEvents2
        {
            private WebBrowser2 parent;

            public WebBrowser2EventHelper(WebBrowser2 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));
            }
        }
    }
    // Represents the method that will handle the WebBrowser2.NavigateError event.
    public delegate void WebBrowserNavigateErrorEventHandler(object sender, WebBrowserNavigateErrorEventArgs e);

    // Provides data for the WebBrowser2.NavigateError event.
    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; }
        }
    }

    // Imports the NavigateError method from the OLE DWebBrowserEvents2  
    // interface.  
    [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);
    }
}