View word document as thumbnails in VB.Net / ASP.Net

[sejal17]

Hello Friends,

I want Application that displays an image preview of a Word document (Like thumbnail View of word document)

Following is my code but i got error on bold part of code


[code=vbnet]
Imports System
Imports System.Text
Imports System.Drawing. Imaging.BitmapD ata
Imports System.Runtime. InteropServices
Imports System.IO
Imports System.Web.UI.W ebControls.Imag e

Partial Class vb
Inherits System.Web.UI.P age


Public Shared Function GetThumbnailIma ge(ByVal fileName As String, ByVal longestEdge As Integer, ByVal colorDepth As Integer) As Image

Dim desktopFolder As IShellFolder
Dim someFolder As IShellFolder
Dim extract As IExtractImage
Dim pidl As IntPtr
Dim filePidl As IntPtr
Dim MAX_PATH As IntPtr


'Manually define the IIDs for IShellFolder and IExtractImage
Dim IID_IShellFolde r = New Guid("000214E6-0000-0000-C000-000000000046")
Dim IID_IExtractIma ge = New Guid("BB2E617C-0920-11d1-9A0B-00C04FC2D6C1")

'Divide the file name into a path and file name
Dim folderName = Path.GetDirecto ryName(fileName )
Dim shortFileName = Path.GetFileNam e(fileName)

'Get the desktop IShellFolder
ShellInterop.SH GetDesktopFolde r(desktopFolder )

'Get the parent folder IShellFolder
desktopFolder.P arseDisplayName (IntPtr.Zero, IntPtr.Zero, folderName, 0, pidl, 0)
desktopFolder.B indToObject(pid l, IntPtr.Zero, IID_IShellFolde r, someFolder)

'Get the file's IExtractImage
someFolder.Pars eDisplayName(In tPtr.Zero, IntPtr.Zero, shortFileName, 0, filePidl, 0)
someFolder.GetU IObjectOf(IntPt r.Zero, 1, filePidl, IID_IExtractIma ge, 0, extract)

'Set the size
Dim size As SIZE
size.cx = 500
size.cy = 500

Dim flags = IEIFLAG.ORIGSIZ E Or IEIFLAG.QUALITY
Dim bmp As IntPtr
Dim thePath = Marshal.AllocHG lobal(MAX_PATH)


'Interop will throw an exception if one of these calls fail.
Try
extract.GetLoca tion(thePath, MAX_PATH, 0, size, colorDepth, flags)
extract.Extract (bmp)
Catch ex As Exception
End Try


'Free the global memory we allocated for the path string
Marshal.FreeHGl obal(thePath)

'Free the pidls. The Runtime Callable Wrappers
'should automatically release the COM objects
Marshal.FreeCoT askMem(pidl)
Marshal.FreeCoT askMem(filePidl )

If Not bmp.Equals(IntP tr.Zero) Then
GetThumbnailIma ge = Image.FromHbitm ap(bmp)- Error (FromHbitmap is not a member of System.Web.UI.W ebControls.Imag e)
' GetThumbnailIma ge = Image(bmp)

Else
GetThumbnailIma ge = Nothing
End If
End Function

Public Enum IEIFLAG As Integer
ASYNC = &H1
CACHE = &H2
ASPECT = &H4
OFFLINE = &H8
GLEAM = &H10
SCREEN = &H20
ORIGSIZE = &H40
NOSTAMP = &H80
NOBORDER = &H100
QUALITY = &H200
End Enum

<StructLayout(L ayoutKind.Seque ntial)> _
Public Structure STRRET_CSTR
Public uType As Integer
<FieldOffset(4) , MarshalAs(Unman agedType.LPWStr )> _
Public pOleStr As String
<FieldOffset(4) > _
Public uOffset As Integer
<FieldOffset(4) , MarshalAs(Unman agedType.ByValA rray, SizeConst:=520) > _
Public strName As Byte()
End Structure

<StructLayout(L ayoutKind.Seque ntial)> _
Public Structure SIZE
Public cx As Integer
Public cy As Integer
End Structure

<ComImportAttri bute(), _
GuidAttribute(" BB2E617C-0920-11d1-9A0B-00C04FC2D6C1"), _
InterfaceTypeAt tribute(ComInte rfaceType.Inter faceIsIUnknown) > _
Public Interface IExtractImage

Sub GetLocation( _
ByVal pszPathBuffer As IntPtr, _
ByVal cch As Integer, _
ByRef pdwPriority As Integer, _
ByRef prgSize As SIZE, _
ByVal dwRecClrDepth As Integer, _
ByRef pdwFlags As Integer)

Sub Extract(ByRef phBmpThumbnail As IntPtr)

End Interface

<ComImportAttri bute(), _
GuidAttribute(" 000214E6-0000-0000-C000-000000000046"), _
InterfaceTypeAt tribute(ComInte rfaceType.Inter faceIsIUnknown) > _
Public Interface IShellFolder

Sub ParseDisplayNam e( _
ByVal hWnd As IntPtr, _
ByVal pbc As IntPtr, _
ByVal pszDisplayName As String, _
ByRef pchEaten As Integer, _
ByRef ppidl As System.IntPtr, _
ByRef pdwAttributes As Integer)

Sub EnumObjects( _
ByVal hwndOwner As IntPtr, _
<MarshalAs(Unma nagedType.U4)> ByVal grfFlags As Integer, _
<Out()> ByRef ppenumIDList As IntPtr)

Sub BindToObject( _
ByVal pidl As IntPtr, _
ByVal pbcReserved As IntPtr, _
ByRef riid As Guid, _
ByRef ppvOut As IShellFolder)

Sub BindToStorage( _
ByVal pidl As IntPtr, _
ByVal pbcReserved As IntPtr, _
ByRef riid As Guid, _
<Out()> ByVal ppvObj As IntPtr)

<PreserveSig( )> _
Function CompareIDs( _
ByVal lParam As IntPtr, _
ByVal pidl1 As IntPtr, _
ByVal pidl2 As IntPtr) As Integer

Sub CreateViewObjec t( _
ByVal hwndOwner As IntPtr, _
ByRef riid As Guid, _
ByVal ppvOut As Object)

Sub GetAttributesOf ( _
ByVal cidl As Integer, _
ByVal apidl As IntPtr, _
<MarshalAs(Unma nagedType.U4)> ByRef rgfInOut As Integer)

Sub GetUIObjectOf( _
ByVal hwndOwner As IntPtr, _
ByVal cidl As Integer, _
ByRef apidl As IntPtr, _
ByRef riid As Guid, _
<Out()> ByVal prgfInOut As Integer, _
<Out(), MarshalAs(Unman agedType.IUnkno wn)> ByRef ppvOut As Object)

Sub GetDisplayNameO f( _
ByVal pidl As IntPtr, _
<MarshalAs(Unma nagedType.U4)> ByVal uFlags As Integer, _
ByRef lpName As STRRET_CSTR)

Sub SetNameOf( _
ByVal hwndOwner As IntPtr, _
ByVal pidl As IntPtr, _
<MarshalAs(Unma nagedType.LPWSt r)> ByVal lpszName As String, _
<MarshalAs(Unma nagedType.U4)> ByVal uFlags As Integer, _
ByRef ppidlOut As IntPtr)

End Interface

Public Class ShellInterop
<DllImport("she ll32.dll", CharSet:=CharSe t.Auto)> _
Public Shared Function SHGetDesktopFol der( _
<Out()> ByRef ppshf As IShellFolder) As Integer
End Function
End Class


End Class

[/code]
If anyone has code that display word document in Thumbnail view then please send me code...

Thanx in Advance........ ..

[CyberSoftHari]

I hink this will help you:
Microsoft Office Thumbnails in SharePoint
(Do not post toomany code part.)

[Frinavale]

Hi Sejal17,

As a full member now, you should know that we expect your code to be posted in [CODE] tags (See How to Ask a Question).
This makes it easier for our Experts to read and understand it. Failing to do so creates extra work for the moderators, thus wasting resources, otherwise available to answer the members' questions.
Please use [CODE] tags in future.

Also, as CyberSoftHari has pointed out, it is a lot easier to understand your problem if you post only the code that is relevant to the problem. Posting all of your code makes it harder to see the problem and harder to help you out.

- Moderator Frinny

[nshergold]

An answer hopefully

Hi sejal,

I was looking into doing this for my web application and couldn't find anything better than your post. I know its been a while since you posted. Well done peicing that together (I assume from the MSDN documentation). Your problem is that you want to return a System.Drawing. Image not a System.Web.UI.W ebControls.Imag e other than that this code should work.

Thanks,
Nat.

[mossmann]

This code does not work. I have been trying it all day.
I think that the MAX_PATH constant (see code line 19) is supposed to be an int, and not an intptr (although I'm not sure, the original code never initializes it...)
I'm currently looking at another solution:



http://www.vbaccelerat or.com/home/net/code/libraries/Shell_Projects/Thumbnail_Extra ction/article.asp

http://www.vbaccelerator.com/home/net/code/libraries/Shell_Projects/Thumbnail_Extraction/article.asp

It's also based around IExtractImage, and it sort of works... However, it does not work on pdfs...

There should be a way to generate pdf thumbnails via imagemagick (google imagemagick pdf thumbnail )
hovever that seems to be quite cumbersome, because , if I have understood this correctly, you would need to install imagemagick, and ghostscript in order for that to work.
Plz if anyone has a fullproof solution to this, post it.
(I am looking for something that can create thumbnails for .doc and .pdf)

[benaref]

Did you find a solution for extracting thumb of docs and pdfs yet ?