How to wait until WebBrowser is completely loaded in VB NET

Question

I am using the WebBrowser control in my VB NET application to load a few URLs    10-15  and save their HTML source in a text file  However  my code doesn t write the source of the current page rather the initial one because the it is triggered even before the page is loaded    How can I wait until the page is completely loaded before calling any event   I tried the following code but it doesn t work   Do Until WebBrowser1 ReadyState   WebBrowserReadyState Complete    Application DoEvents   Loop

User · Answer

Another option is to check if it s busy with a timer   Set the timer as disabled by default  Then whenever navigating  enable it  i e    WebBrowser1 Navigate  https   www somesite com   tmrBusy Enabled   True   And the timer       Private Sub tmrBusy Tick sender As Object  e As EventArgs  Handles tmrBusy Tick          If WebBrowser1 IsBusy   True Then              Debug WriteLine  WB Busy                Else              Debug WriteLine  WB Done                tmrBusy Enabled   False          End If      End Sub

User · Answer

I made similar function  only that works to me   sorry it is in C  but easy to translate     private void WaitForPageLoad            while  pageReady    false           Application DoEvents          while  webBrowser1 IsBusy    webBrowser1 ReadyState    WebBrowserReadyState Complete           Application DoEvents

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In the load events  use Me Hide    In WebBrowser1 DocuementCompleted  use Me Show

User · Answer

Sounds like you want to catch the DocumentCompleted event of your webbrowser control    MSDN has a couple of good articles about the webbrowser control - WebBrowser Class has lots of examples  and How to  Add Web Browser Capabilities to a Windows Forms Application

User · Answer

Salvete  I needed  simply  a function I could call to make the code wait for the page to load before it continued   After scouring the web for answers  and fiddling around for several hours  I came up with this to solve for myself  the exact dilemma you present  I know I am late in the game with an answer  but I wish to post this for anyone else who comes along   usage   just call WaitForPageLoad   just after a call to navigation   whatbrowser Navigate  http   www google com   WaitForPageLoad     another example we don t combine the navigate feature with the page load  because sometimes you need to wait for a load without also navigating  for example  you might need to wait for a page to load that was started with an invokemember event   whatbrowser Document GetElementById  UserName   InnerText   whatusername whatbrowser Document GetElementById  Password   InnerText   whatpassword whatbrowser Document GetElementById  LoginButton   InvokeMember  click   WaitForPageLoad     Here is the code  You need both subs plus the accessible variable  pageready  First  make sure to fix the variable called whatbrowser to be your webbrowser control  Now  somewhere in your module or class  place this   Private Property pageready As Boolean   False   Region  Page Loading Functions      Private Sub WaitForPageLoad           AddHandler whatbrowser DocumentCompleted  New WebBrowserDocumentCompletedEventHandler AddressOf PageWaiter          While Not pageready             Application DoEvents           End While         pageready   False     End Sub      Private Sub PageWaiter ByVal sender As Object  ByVal e As WebBrowserDocumentCompletedEventArgs          If whatbrowser ReadyState   WebBrowserReadyState Complete Then             pageready   True             RemoveHandler whatbrowser DocumentCompleted  New WebBrowserDocumentCompletedEventHandler AddressOf PageWaiter          End If     End Sub   End Region

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I struggled with this  fully loaded  issue for some time but found the following solution worked for me  I m using IE7  so I m not sure if this works in other versions  but worth a look   I split the problem into two parts  first I needed a message from the DocumentComplete event    Private Sub WebBrowser1 DocumentComplete ByVal pDisp As Object  URL As Variant     fullyLoaded   True End Sub   Then in the part of code where I need to wait till the web page has fully loaded I call another sub that does this   Private Sub holdBrowserPage        fullyLoaded   False      Do While fullyLoaded   False          DoEvents      Loop       fullyLoaded   False End Sub   In addition  I also needed to do the same thing whilst waiting for javascript code to complete  For instance on one page when you select an item from an html drop down list  it populated the next drop down list  but took a while to reveal itself  In that instance I found calling this   Private Sub holdBrowser   Do While WebBrowser1 Busy Or WebBrowser1 ReadyState  lt  gt  READYSTATE COMPLETE    DoEvents Loop End Sub   was enough to hold the browser  Not sure if this will help everyone  as a combination of IE7  the website I was loading  and the javascript that the page was running alone might have allowed this solution  but certainly worth a try

User · Answer

Technically  there are two issues with the code posted by BGM    the adding of the handlers in the WaitForPageLoad method is potentially too late  The navigation is initiated before the handlers are added which means that in very rare cases where the browser already has the page it may complete before the handlers are added in which case you will miss the event and sit forever waiting   The solution is to add the handlers before the navigation starts and remove them after the navigation completed  This means the WaitForPageLoad method needs to be split into two methods  One is called before initiating the navigation  It should set the handlers  The second part does the ReadyState monitoring and cleans up when  Ready   good programming practices is to add a timeout so that a lost  or crashed  or looping  browser doesn t make your code wait forever for the document completed even

User · Answer

Sometimes if you use JavaScript the DocumentComplete event don t return the right answer  I use the event ProgressChanged instead   Private Sub WebBrowser1 ProgressChanged sender As Object  e As WebBrowserProgressChangedEventArgs  Handles WebBrowser1 ProgressChanged          Console WriteLine  Current Progress      e CurrentProgress ToString           If e CurrentProgress   e MaximumProgress Then                The maximum progress is reached             load started   True          End If            The page is confirmed downloaded after the progress returns to 0         If e CurrentProgress   0 Then              If load started Then                    The page is ready to print or download                    WebBrowser1 Print                   load started   False              End If          End If  End Sub

User · Answer

Hold on     From my experience  you SHOULD make sure that the DocumCompleted belongs to YOUR URL and not to a frame sub-page  script  image  CSS  etc  And that is regardless of the IsBusy or the ReadyState is finished or not  which both are often inaccurate when page is slightly complex   Well  that is my own personal experience  on a working program of VB 2013 and IE11  Let me also mention that you should take into account also the compatibility mode IE7 which is ON by default at the webBrowser1     Page  sub-frame or resource was totally loaded  Private Sub webBrowser1 DocumentCompleted sender As Object         e As WebBrowserDocumentCompletedEventArgs         Handles webBrowser1 DocumentCompleted        Check if finally the full page was loaded  inc  sub-frames  javascripts  etc      If e Url ToString   webBrowser1 Url ToString Then           Only now you are sure          fullyLoaded   True     End If  End Sub

[vb.net] How to wait until WebBrowser is completely loaded in VB.NET?

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