export one library in multiple site

• I will show how to create a custom web part that represents a list or library’s view and use this web part in other sites (at least in the same site collection) without copying documents between sites. 
• This custom web part supports a tool bar so files can be uploaded and maintained in a single library, but viewed and maintained from any site in the site collection that has this web part. 
• Tools needed:
  • SharePoint Designer (to make one quick change, export the web part, and then optionally roll back the change)
  • Some way to find the site’s GUID (see link to a tool below)
• First some observations:
  • While editing a web part page, click a web part’s menu and you will usually see an Export option, except for list and library web parts.
  • List and library view pages are web part pages (they have “Edit Page” in the Site Actions menu") and the displayed list is a web part.
• So how can you export a list web part?
  Turns out to be pretty easy. Edit the page in SharePoint Designer and change one word.
  1. Open the site in SharePoint Designer and double click on a page with the web part (default.aspx, Shared Documents/Forms/Allitems.aspx, etc)
  2. In the code view find the web part and find 
     <ExportControlledProperties>false</ExportControlledProperties> 
     and change from “false” to “true”
  3. Save the page (this will “unghost” the page, but you can undo the changes after the export is complete – right-click the file in the Folder List and select Reset to Site Definition)
  4. Go to a browser and visit this page. Go to Site Actions, Edit Page.
  5. Click Edit in web part you just modified and click Export.
  6. Give the file a name and save it somewhere where you can find it in the next step.
  To import the exported settings as a new web part:
  1. Visit your top level site in the site collection and go to Site Actions, Site Settings, and in the Galleries column click Web Parts
  To add the web part.
  1. Nothing special here. Add this web part just like any other web part.
  
  
  Some differences…
  Oddly, the displayed columns are different. The AllItems view displayed Type, Name, Modified and Modified By. The new web part displays Type, Name and Modified By. This is easy to fix. Edit the web part and change the Selected View property to All Documents then you will get the same list of columns in both displays.
  The new web part does not display a toolbar by default, but this can be enabled from the web part’s properties panel. If the toolbar is enabled you will see all of the buttons found in the AllItems page, New, Upload, Actions and Settings (depending on the current user’s security rights).
  
  
  Now test the web part in a sub site….
  Error!
      Unable to add selected web part(s).
      List does not exist.
      The page you selected contains a list that does not exist.
  On the first attempt it appears that the new exported web part will not work on another site. Time for more research…
  
  
  Find the missing GUID
  Open the .DWP (.WEBPART in 2010) file created by the Export. Find these two lines:
  SP 2007
     <ListName …..>{ list_guid_here } </ListName>
     <WebId ….> all_zeros_guid_here </WebId>
  SP 2010
     <property name="ListName" type="string">{ list_guid_here } </property>
     …
     <property name="WebId" …>all_zeros_guid_here </property>
  
  
  SharePoint uses Globally Unique IDs (GUIDS) to identify just about everything stored in the databases. Notice that the ListName has a GUID, but the WebId is all zeros. Replace the zeros with the GUID for the site that owns the list and all will then work.
  
  
  How to find a GUID
  I can’t find any place in the the pages exposed in SharePoint Designer where the web site’s GUID is used, although the list’s GUID can be found in some of the URLs (for example after clicking Settings, List or Library Settings). I wrote two little utilities to display a site’s GUIDs, one a Windows application and the other a page you can deploy to the LAYOUTS folder on the server.
  See: http://techtrainingnotes.blogspot.com/2009/03/sharepoint-finding-sharepoint-guids.html
  Quick note: Internally a site is call a “web” and a site collection is called a “site”. (go figure…) The utilities above use the web and site names.
  
  
  Update the web part file
  Edit the WebId element and replace the all zeros GUID with the site’s GUID:
    SP 2007”   <WebId ….> all_zeros_guid_here </WebId>
    SP 2010    <property name="WebId" …>all_zeros_guid_here </property>
  After updating the DWP file with the site’s (web’s) GUID, re-upload it to the web part gallery and go and test the web part in a sub site.
  
  And for the “Strange Things” list… the GUID for the web site does not include brackets ( { } ) and is in lower case. The GUID for the list must have brackets and MUST be in UPPER CASE or it will not work.
  
  
  
  
  Reference:http://techtrainingnotes.blogspot.com/2009/03/sharepoint-one-library-multiple-sites.html