InvalidOperationException-feil med webbrowser

[dabear]

Heisann. Prøver meg på å endre et webdokument inne i en browser, gjennom Document object model (DOM), men det ser ikke ut til å fungere, jeg får følgende feilmelding:

Klikk for å se/fjerne innholdet nedenfor

System.InvalidOperationException was unhandled

  Message="An error occurred creating the form. See Exception.InnerException for details.  The error is: Object reference not set to an instance of an object."

  Source="BrowserTest"

  StackTrace:

      at BrowserTest.My.MyProject.MyForms.Create__Instance__[T](T Instance) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 190

      at BrowserTest.My.MyProject.MyForms.get_Form1()

      at BrowserTest.My.MyApplication.OnCreateMainForm() in C:\Documents and Settings\Bjørn\My Documents\Visual Studio 2005\Projects\BrowserTest\BrowserTest\My Project\Application.Designer.vb:line 35

      at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()

      at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()

      at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)

      at BrowserTest.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81

      at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)

      at System.Runtime.Hosting.ManifestRunner.Run(Boolean checkAptModel)

      at System.Runtime.Hosting.ManifestRunner.ExecuteAsAssembly()

      at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext, String[] activationCustomData)

      at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext)

      at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone()

      at System.Threading.ThreadHelper.ThreadStart_Context(Object state)

      at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)

      at System.Threading.ThreadHelper.ThreadStart()

 

Dette er altså når jeg ikke håndterer exception-en, det ser ut til at det er linja 'divBox = browser.Document.CreateElement("div")' som feiler. Hvordan kan jeg utføre det jeg vil?

 

    Public Sub Browser_Resizing(ByVal sender As Object, ByVal e As System.EventArgs) Handles Browser1.Resize

 

      ' MessageBox.Show(sender.ToString())

        Dim browser As System.Windows.Forms.WebBrowser = Browser1

        Dim doc As System.Windows.Forms.HtmlDocument = browser.Document

        Dim divBox As System.Windows.Forms.HtmlElement

 

        Try

            divBox = doc.CreateElement("div")

        Catch ex As Exception

            MessageBox.Show("failed")

            Return

        End Try

 

 

        divBox.Style = "color:red, margin:1px solid green"

        divBox.InnerHtml = String.Format("Bredde: {0}, høyde: {1}", "bredde1", "høyde1") 'Browser.Width, Browser.Height)

        Try

            doc.GetElementsByTagName("body").Item(0).AppendChild(divBox)

        Catch ex As Exception

 

        End Try

 

    End Sub

Endret 4. september 2007 av dabear

[dabear]

Sjekka bare om browseren ikke var lik nothing, og alt blei bra