Archive: SwyxIt Full-Text Search Plug-in in C#

[Tom Wellige]

The following blog post is restored from the Swyx Forum Archive (2007-2014) and was posted originally at 26.11.2008 in "Martin's Blog".

 

Before you continue you should read the first part about how to write a SwyxIt Plug-In in managed code. This blog post extends the first sample and adds full-text search support.

SwyxIt can ask a plug-in to find a number for a name, e.g. when you use the phonebook search function. A plug-in needs to support this custom COM interface which is defined in the SDK (CLMGgrPub.idl):

 

[ 
   object,
   uuid(f8e55548-4c00-11d3-80bc-00105a653379),

   helpstring("IFulltextSearchAddIn Interface"),
   pointer_default(unique)
]
interface IFulltextSearchAddIn : IUnknown
{
   HRESULT FulltextSearchInContacts(
      [in] BSTR bstrSearchText, 
      [in] BOOL bEnableSearchInNumbers, 
      [in] IDispatch* pISearchResultCollection);        
};

 

In managed code this interface definition is

 

[ComVisible(true)] 
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown),
 Guid("f8e55548-4c00-11d3-80bc-00105a653379"),
 AutomationProxy(false)]
public interface IFulltextSearchAddIn
{
    [PreserveSig()]
    [return: MarshalAs(UnmanagedType.Error)]
        int FulltextSearchInContacts(
        [MarshalAs(UnmanagedType.BStr), In()] string searchText,
        [MarshalAs(UnmanagedType.Bool), In()] bool enableSearchInNumbers,
        [MarshalAs(UnmanagedType.IDispatch), In(), Out()] object searchResultCollection);
}

 

The interface has some unusual semantics. The third parameter is an IDispatch based interface which is defined in CLMgrPub.idl like this:

 

[ 
    object,
    uuid(f8e55543-4c00-11d3-80bc-00105a653379),
    dual,
    helpstring("INameNumberSearchResultCollection Interface"),
    oleautomation,
    pointer_default(unique)
]
interface INameNumberSearchResultCollection : IDispatch
{
   [propget, restricted, id(DISPID_NEWENUM)] 
   HRESULT _NewEnum([out, retval] IUnknown** pVal);

   [id(DISPID_VALUE)]
    HRESULT Item([in] VARIANT index, [out, retval] VARIANT* pVariant);

   [propget, id(1)] 
   HRESULT Count([out, retval] long *pVal);

   [propget, id(2)] 
   HRESULT CreateItem([out, retval] IDispatch** ppVal);

   [id(3)]
   HRESULT AddItem([in] IDispatch* pVal);
};

 

It’s an input parameter, i.e. SwyxIt provides such a collection object to your plug-in. You just have to fill it with data.

As you can see from the definition INameNumberSearchResultCollection is an automation interface. We can just add a COM reference to clmgr.exe to our project in Visual Studio and the framework creates a runtime callable wrapper (RCW) for it. The items in this collection are NameNumberSearchResult objects. Fortunately the interface of that object is an automation interface too and the RCW has a definition of it, too.

Here’s a small sample implementation of the search function:

 

  1: public int FulltextSearchInContacts( 
  2:        string searchText, 
  3:        bool enableSearchInNumbers, 
  4:        object searchResultCollection)
  5: {
  6:     NameNumberSearchResultCollection resultCollection = (NameNumberSearchResultCollection)searchResultCollection;
  7: 
  8:          // This is a sample, we find "Swyx" only. 
  9:          // Note: Swyxit always provides lower case text.
 10:          if (searchText.Contains("swyx"))
 11:     {
 12:         NameNumberSearchResult result = new NameNumberSearchResult();
 13:         result.Name = "Swyx Solutions AG (SampleAddIn result)";
 14:         result.Number = "+4923147770";
 15:         resultCollection.AddItem(result);
 16:     }
 17: 
 18:         return 0;
 19: }
 20: 

 

As you can see on line 6 the third parameter can be casted to a NameNumberSearchResultCollection. You just have to implement your search logic, create NameNumberSearchResult for each result and add it to the collection with AddItem() (lines 12 to 15).

 

Important: Per default full-text search is not enabled for SwyxIt! plug-ins. You have to create a REG_DWORD registry value named

FulltextSearchAddinEnabled

and set it to 1. It’s located in the registry key of your plug-in (See the previous blog entry). Without that registry value SwyxIt does not use the plug-in’s IFullTextSearchAddIn interface.

 

Last, but not least, here’s the updated sample plugin from the previous post. Have fun.

 

CSharpAddIn.zip