Catch 404 error exception on web browser control

Question

How can I catch 404 error on web browser control?

 

 Try
  TimeTable.Navigate("URL/File.htm")
 Catch ex As Exception
  TimeTable.Navigate("URL/File2.html")
End Try

It still show 404 error on the control.

Answer 1

How can I catch 404 error on web browser control?

 

 Try



 TimeTable.Navigate("URL/File.htm")



 Catch ex As Exception



 TimeTable.Navigate("URL/File.html")



End Try

It still show 404 error on the control.

Hello duanebytes,

The 404 error indicates that we could not find the requested URL, try typing another URL to see if a problem
code or actually find the page you want does not exist.

Try

 TimeTable.Navigate("URL\File.htm")

 Catch ex As Exception

 TimeTable.Navigate("URL\File.html")

End Try

Hello

---

Carmelo La Monica  http://community.visual-basic.it/carmelolamonica/

Answer 2

How can I catch 404 error on web browser control?

 

 Try



 TimeTable.Navigate("URL/File.htm")



 Catch ex As Exception



 TimeTable.Navigate("URL/File.html")



End Try

It still show 404 error on the control.

Hello duanebytes,

The 404 error indicates that we could not find the requested URL, try typing another URL to see if a problem
code or actually find the page you want does not exist.

Try

 TimeTable.Navigate("URL\File.htm")

 Catch ex As Exception

 TimeTable.Navigate("URL\File.html")

End Try

Hello

---

Carmelo La Monica  http://community.visual-basic.it/carmelolamonica/

I'm sorry. In my post above. after the Catch. The file name should be a different name. File2.html. Sorry my bad.

Fixed in the first post.

And I'm sure that File2.html exists.

Answer 3

You get the 404 returned from a webserver, it is not really an error which you can catch, because the navigate function is doing it correct.

 

---

Success
Cor

Answer 4

Hello,

the  HTTP Status Codes are realised on http network protocol. You cannot catch them as exception.

But You can handle the errors on this way:

Dim response As HttpWebResponse = request.GetResponse() 

 If response.StatusCode = HttpStatusCode.OK Then

 Sorry I've overlooked something. webbrowser control:

gets the status of the browser :StatusTextChanged

regards Ellen

---

Ich benutze/ I'm using VB2008 & VB2010

Answer 5

(I appologize if this is a duplicate. I thought I posted a while ago...)

 

Try the following translated from an old C# post on the same question:

 

Option Strict On
Public Class Form1
 Private Sub Button1_Click _
  (ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  WebBrowser1.Navigate("http://localhost/foo.bar")
 End Sub
 Private Sub ErrorHandler(ByVal pDisp As Object, ByRef URL As Object, ByRef Frame As Object,
  ByRef StatusCode As Object, ByRef Cancel As Boolean)
  If (StatusCode.ToString() = "404") Then
   MessageBox.Show("404...")
  End If
 End Sub
 Private Sub Form1_Shown(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Shown
  Dim axBrowser As SHDocVw.WebBrowser
  axBrowser = CType(WebBrowser1.ActiveXInstance, SHDocVw.WebBrowser)

 

  AddHandler axBrowser.NavigateError, AddressOf ErrorHandler
 End Sub
End Class

--
Mike

Answer 6

Mike,

I just try Your code. I cannot reach the NavigateError Event.

Handles WebBrowser1.  ... this event not displayed

Ellen

---

Ich benutze/ I'm using VB2008 & VB2010

Answer 7

Do you have a webbrowser control named WebBrowser1 on your form?

--
Mike

Answer 8

Sorry Ellen, I neglected to mention you need to add a COM reference to "Microsoft Internet Controls".

--
Mike

Answer 9

Mike, I have this webbrowser control:

 Friend WithEvents WebBrowser1 As System.Windows.Forms.WebBrowser

Ellen

---

Ich benutze/ I'm using VB2008 & VB2010

Answer 10

Mario Cossi made an interesting observation regarding the DocumentType at

http://social.msdn.microsoft.com/forums/en-US/netfxnetcom/thread/3557dd12-252b-49be-9572-1d647eb36991/

"As for the detection of errors, the documentation offers no direct solution to the problem. Yet, there might be an undocumented workaround: the DocumentType property is "HTML document" when a page is displayed, but becomes "" whenever the page or the server do not exist. This seems to be true even if the server redirects you to a custom 404 page."

I tried checking it in the DocumentCompleted event, and it does seem to work.

Addendum: I switched off IIS on my machine, and got "File" for the DocumentType when trying to navigate to a page on 127.0.0.1.

--
Andrew

Answer 11

Hello,

the  HTTP Status Codes are realised on http network protocol. You cannot catch them as exception.

But You can handle the errors on this way:

Dim response As HttpWebResponse = request.GetResponse() 

 If response.StatusCode = HttpStatusCode.OK Then

 Sorry I've overlooked something. webbrowser control:

gets the status of the browser :StatusTextChanged

regards Ellen

---

Ich benutze/ I'm using VB2008 & VB2010

Private Sub WB_StatusTextChanged(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserNavigatingEventArgs) Handles WB.StatusTextChanged
        Dim response As HttpWebResponse = request.GetResponse()
        If response.StatusCode = HttpStatusCode.OK Then
        Else
            WB.Navigate("URL/File2.html")
        End If

    End Sub
Does not work

Answer 12

Hello,

HttpWebResponse is anoher technique. Please try this code:

Private Sub WB_StatusTextChanged(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserNavigatingEventArgs) Handles WB.StatusTextChanged

Me.label1.Text = WB.StatusText

  End Sub

Create a new label on the form to display text. Does the event fire?

regards Ellen

 

---

Ich benutze/ I'm using VB2008 & VB2010

Answer 13

Hello,

HttpWebResponse is anoher technique. Please try this code:

Private Sub WB_StatusTextChanged(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserNavigatingEventArgs) Handles WB.StatusTextChanged

Me.label1.Text = WB.StatusText

 End Sub

Create a new label on the form to display text. Does the event fire?

regards Ellen

 

---

Ich benutze/ I'm using VB2008 & VB2010

Sorry for the late reply, was busy. Tried what you suggested, the label.text changes from "Label1" to ""

Answer 14

Hello,

I've found a soulution. It works. Make a new Windows forms project, no changes in formdesigner and copy the code into the emtpy code window.

success and best regards Ellen

http://social.msdn.microsoft.com/Forums/de-DE/visualbasicde/thread/292445fe-cd1c-450d-8ab8-5dd9cc1fbccd/#d068e8c1-8f33-4efd-8b94-13ebb1b139f0

link to CreateSink Method

---

Ich benutze/ I'm using VB2008 & VB2010

Answer 15

Hello,

I've found a soulution. It works. Make a new Windows forms project, no changes in formdesigner and copy the code into the emtpy code window.

success and best regards Ellen

http://social.msdn.microsoft.com/Forums/de-DE/visualbasicde/thread/292445fe-cd1c-450d-8ab8-5dd9cc1fbccd/#d068e8c1-8f33-4efd-8b94-13ebb1b139f0

link to CreateSink Method

---

Ich benutze/ I'm using VB2008 & VB2010

That's quite a long line of code. I'll try to understand and post results soon.

And wb = Web browser control right?

Answer 16

And wb = Web browser control right?

Hello,

Yes it's ok. Take a look to this line:

Private WithEvents wb As New WebBrowser2()

regards Ellen

 

---

Ich benutze/ I'm using VB2008 & VB2010

Answer 17

And wb = Web browser control right?

Hello,

Yes it's ok. Take a look to this line:

Private WithEvents wb As New WebBrowser2()

regards Ellen

 

---

Ich benutze/ I'm using VB2008 & VB2010

Thanks Ellen.

Answer 18

If the page is valid, it doesn't navigate to the site. Help?
Oh I have found what my problems are:

In the Load event there's this code:

Controls.Add(wb)

I also added a WebBrowser control with the name WebBrowser2 so it kinda replaces the Web Browser.

It works now.

Answer 19

How can I do this if the controls are already on my form? I got this error:

'HomeworksBrowser' is already declared as 'Friend WithEvents HomeworksBrowser As System.Windows.Forms.WebBrowser' in this class.

Answer 20

Hmm,

Private WithEvents wb As New WebBrowser2()

does not make a instance of webBrowser. But the webBrowser2 is inherits from webBrowser.

It seems; that You make second instance by draging the control on to the form?

 

---

Ich benutze/ I'm using VB2008 & VB2010

Answer 21

Hmm,

Private WithEvents wb As New WebBrowser2()

does not make a instance of webBrowser. But the webBrowser2 is inherits from webBrowser.

It seems; that You make second instance by draging the control on to the form?

 

---

Ich benutze/ I'm using VB2008 & VB2010

Yes. The web browser are already on my form.