VB.Net: Tabcontrol and webbrowser control

[geertvdijk]

I've got this little wannabe-webbrowser project that uses the Webbrowser control inside a Tabcontrol.
For opening a new tab+browser I've got this:

Dim n As Integer
Dim w as New WebBrowser
n = tabcontrol1.TabPages.Count + 1
Dim t As New TabPage
t.Text = "Page " & n
w.Dock = DockStyle.Fill
w.Navigate("about:blank")
t.Controls.Add(w)
Me.TabControl1.Controls.Add(t)

Now once I've got it up, how can I tell the Tabcontrol1.Selectedtab's webbrowser control to navigate to cboURL.text?
So, with other words, what should be in place of x in the following lines of code:

cboURL.Items.Add(cboUrl.Text)
x.Navigate(cboUrl.Text)

?

Thnx in advance, graey.

[Phil Weber]

w.

cboURL.Items.Add(cboUrl.Text)
w.Navigate(cboUrl.Text)

[geertvdijk]

im sorry if I was unclear.
every webbrowser is called w.
So on tab 1 a browser is called w, on tab 2 a browser is called w, and so on...
and also these arent public declarations, so W is only available within the form's load event...

[Phil Weber]

I would probably create a form-level collection (e.g., ArrayList) to contain the WebBrowser controls. Then you could do this:

Dim w As New WebBrowser
BrowserCollection.Add(w)
.
.
.
Dim ActiveBrowser As WebBrowser = CType(BrowserCollection(TabControl1.TabIndex), WebBrowser)
ActiveBrowser.Navigate(cboUrl.Text)

[geertvdijk]

hmm im using vb.net 2005, dunno if that should give difficulties, but i get an error when adding a browser to the arraylist:

[title]NullReferenceException was unhandled.[/title]
Object reference not set to an instance of an object.

as Im new to .net, I don't know what to do with this...

[Phil Weber]

Please post your code.

[geertvdijk]

Public Class Main
Public i As Integer
Dim Browsercollection As ArrayList




Private Sub newtabToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles newtabToolStripMenuItem.Click
Dim w As New WebBrowser
Dim t As New TabPage
t.Controls.Add(w)
Browsercollection.Add(w)
cboURL.Width = (Me.Width / 2)
w.Dock = DockStyle.Fill
w.Navigate("about:blank")
t.Text = "Tab " & i
tabControl1.Controls.Add(t)
i = i + 1
End Sub

Private Sub cmdGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGo.Click
cboURL.Items.Add(cboURL.Text)
Dim ActiveBrowser As WebBrowser = CType(Browsercollection(tabControl1.TabIndex), WebBrowser)
ActiveBrowser.Navigate(cboURL.Text)
End Sub

End Class

Obviously there were some more items in it, but these are not important (like wether the statusbar is visible and stuff).

[Phil Weber]

You're declaring a variable of type ArrayList, but you're never creating an instance of it (New).

Change:
Dim BrowserCollection As ArrayList

To:
Dim BrowserCollection As New ArrayList

Generally, when you get a NullReferenceException it means you've forgotten a New.

[geertvdijk]

thnx
however this error pops up now:

ArgumentOutOfRangeException was unhandled.
Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

Code:

    Private Sub cmdGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGo.Click
        cboURL.Items.Add(cboURL.Text)
        (this line gave the error)Dim ActiveBrowser As WebBrowser = CType(Browsercollection(tabControl1.TabCount), WebBrowser)
        ActiveBrowser.Navigate(cboURL.Text)
    End Sub

EDIT: i changed tabcontrol1.tabindex into tabcount, still the same error tho...

[Phil Weber]

OK, you should be able to figure that out: What is the value of tabControl1.TabIndex when the error occurs? How may items are in the BrowserCollection arraylist? Do the math. ;-)

[geertvdijk]

the strange thing is, no matter how many tabs are open, tabindex is always 6...
and logicly tabcount doesnt work cause it doesnt show the active tabs nr....

[geertvdijk]

i see, in vb.net 2005 it is selectedindex...
dunno how it is in earlier .net versions btw... xD

[Phil Weber]

Sorry, my mistake. TabIndex is the control's position in the tab order.

[geertvdijk]

ofcourse i could have know that xD
thanks for all of your help, tho...
is there btw any way of calling the webbrowser's find/replace form? xD

[yz4now]

Hello,

I am trying to do the same make a simple browser with tabs and when I tried out what is above it didn't work for me?

I get this error:

Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

Would anyone know why?

My Code is like this:

Dim w As New WebBrowser
BrowserCollection.Add(w)
Dim ActiveBrowser As WebBrowser = CType(BrowserCollection(Me.TabControl1.SelectedIndex), WebBrowser)
ActiveBrowser.Navigate(Me.ComboBox1.Text)