Represents a document exposed within a document library by using a graphical icon. Each preconfigured document type in SharePoint Products and Technologies has a corresponding document icon entry in a server configuration file, but other file formats might lack the appropriate icon.
Real World Example
A bug tracker application uses files with a unique file format that is not supported by default in SharePoint Products and Technologies. For bug tracker files to appear correctly in the document libraries, you must install a new icon to support the bug tracker file format within SharePoint Products and Technologies.
Document icon references are registered in the server-side DOCICON.XML file located in the following path:
%COMMONPROGRAMFILES%\Microsoft Shared\web server extensions\12\TEMPLATE\XML\DOCICON.XML
The actual graphic images of the document icons are usually stored in the IMAGES directory:
%COMMONPROGRAMFILES%\Microsoft Shared\web server extensions\12\TEMPLATE\IMAGES\
The DOCICON.XML file also indicates how the file type is activated (for example, when opening .docx or .doc files directly in Microsoft Office Word), but these settings, like the icons, become globally available to the SharePoint environment. The following is an example of the items in the DOCICON.XML file.
<Mapping Key="asmx" Value="icasmx.gif" OpenControl=""/> <Mapping Key="asp" Value="ichtm.gif" OpenControl=""/> <Mapping Key="aspx" Value="ichtm.gif" EditText="Microsoft Office SharePoint Designer" OpenControl="SharePoint.OpenDocuments"/> <Mapping Key="bmp" Value="icbmp.gif"/>
Addition of a document icon adjusts only how it is rendered in lists or search results, and does not extend to client Office system programs or to the Explorer view of a document library. In Microsoft Office SharePoint Server 2003, document icons had to adhere to a specific naming convention to show up in search results, but this is no longer necessary with Microsoft Office SharePoint Server 2007 and Windows SharePoint Services 3.0.
The <OpenControl> tag included in the DOCICON.XML file, which indicates how the file type is activated or edited, can be set to refer to a new client-side DLL that is used to create or edit the specified control If you set this to any setting other than the default listed in the Windows SharePoint Services 3.0 SDK, then you must deploy the client DLL to each client that accesses the SharePoint environment.
A modified DOCICONS.XML file applies only to a single server, and must be copied to every server in a server farm for the icon to be displayed consistently. An IISReset command is required for the changes to the DOCICONS.XML file to be reflected in a rendered page.
Service packs or hot fix patches can overwrite changes to the DOCICON.XML file. Therefore you should package the changes in a format that can be easily reapplied. This makes it less likely that your changes will be overlooked or applied incorrectly if they are manually updated later.