Find the rendered image memory address of a Webbrowser Control

• • Reply

  12 years ago

  by gregcost

  gregcost

  , United States

  Joined 17 years ago

  I have been using IHTML2Element for quite some time to thumbnail a WebBrowser screen’s image and it
  works fine…except now xsl/xml rendered HTML is not available in IHTML2Element.  I have developed code
  to go after the memory address of the Desktop Window and have successfully thumb nailed the desktop
  screen from memory with a form on it hosting a WebBrowser control on it.  This is not a screen scrap
  or copy from screen operation I have the desktop windows memory address and I am using StretchBlt from
  that address in memory to a thumbnail.

  Being able to use IHTMLElement to thumbnail WebBrowser controls allows me to create thumbnails of hosted
  webBrowser without displaying them.  This is what I am looking to do only now from finding the address
  where webBrowser controls are fully rendered in memory.  

  
  I thought I could just use Me.WebBrowser1.handle and that would point to where the rendered HTML lives…
  but that did not work.

  The following code below works fine for the Desktop window:
  

  Try

              'Handle for the desktop window
              Dim AddrDesktopWindow As IntPtr
              If AddrDesktopWindow = 0 Then AddrDesktopWindow = GetDesktopWindow

              'getWindow Size
              Dim rcWindow As RECT
              GetWindowRect(AddrDesktopWindow, rcWindow)
              Dim WinHeight As Integer = rcWindow.Right - rcWindow.Left
              Dim WinWidth As Integer = rcWindow.Bottom - rcWindow.Top

              Dim PB1 As Graphics = Me.PictureBox1.CreateGraphics
              Dim AddrOfPB1 As IntPtr = PB1.GetHdc

              Dim AddrOfPictureBox1 As IntPtr = Me.PictureBox1.Handle

              'create a compatible DC
              Dim AddrCreateCompatibleDC As IntPtr = CreateCompatibleDC(IntPtr.Zero)

              'create a memory bitmap in the DC just created, the size of the window we're capturing
              Dim AddrCreateCompatibleBitmap As IntPtr = CreateCompatibleBitmap(AddrOfPB1, WinWidth, WinHeight)

              'Prepare DC as a Bitmap using selectObject to configure the DC
              SelectObject(AddrCreateCompatibleDC, AddrCreateCompatibleBitmap)

              'copy the screen image into the DC
              BitBlt(AddrCreateCompatibleDC, 0, 0, WinWidth, WinHeight, GetWindowDC(AddrDesktopWindow), 0, 0, SRCCOPY)

              'Clone image of PictureBox1 to Picturebox2 when the IMAGE is in the Device Context
              '#### BitBlt(AddrOfPB1, 0, 0, WinWidth, WinHeight, AddrCreateCompatibleDC, 0, 0, SRCCOPY)
              StretchBlt(AddrOfPB1, 0, 0, 100, 100, AddrCreateCompatibleDC, 0, 0, WinWidth, WinHeight, TernaryRasterOperations.SRCCOPY)

              PB1.ReleaseHdc(AddrOfPB1)
              CType(PB1, IDisposable).Dispose()
              DeleteDC(AddrCreateCompatibleDC)
              DeleteObject(AddrCreateCompatibleBitmap)

          Catch ex As System.NullReferenceException
              MsgBox("--- NullReferenceException ---" & "  " & _
              vbCrLf & "Message --- " & ex.Message & "  " & _
              vbCrLf & "Source --- " & ex.Source & "  " & _
              vbCrLf & "StackTrace --- " & ex.StackTrace & "  " & _
              vbCrLf & "TargetSite --- " & ex.TargetSite.ToString)
              ' Code reacting to NullReferenceException
          Catch ex As Exception
              ' Code reacting to any exception
              MsgBox(vbCrLf & "Message --- " & ex.Message & "  " & _
              vbCrLf & "Source --- " & ex.Source & "  " & _
              vbCrLf & "StackTrace --- " & ex.StackTrace & "  " & _
              vbCrLf & "TargetSite --- " & ex.TargetSite.ToString)
          End Try
      End Sub

  
   

  Report abuse