Text Service Registration

In addition to the standard COM in-proc server registry entries, a text service must register itself with the Text Services Framework (TSF) so that it can be available for use with an application. TSF supplies the ITfInputProcessorProfiles and ITfCategoryMgr interface to simplify the registration process.

Text service providers should also provide digital signatures with their binary executables. See Introduction to Code Signing.

Registering the Text Service

A text service registers itself with TSF by calling ITfInputProcessorProfiles::Register with the class identifier of the text service. An instance of the ITfInputProcessorProfiles interface is obtained by calling CoCreateInstance with CLSID_TF_InputProcessorProfiles.

The following example demonstrates how to create an ITfInputProcessorProfiles object and register the text service.

BOOL RegisterTextService(CLSID clsidTextService)
{
    HRESULT hr;
    ITfInputProcessorProfiles *pInputProcessProfiles;

    hr = CoCreateInstance(  CLSID_TF_InputProcessorProfiles, 
                            NULL, 
                            CLSCTX_INPROC_SERVER,
                            IID_ITfInputProcessorProfiles, 
                            (LPVOID*)&pInputProcessProfiles);

    if (hr != S_OK)
    {
        return FALSE;
    }

    hr = pInputProcessProfiles->Register(clsidTextService);

    pInputProcessProfiles->Release();
    
    return (S_OK == hr);
}

ITfInputProcessorProfiles::Unregister

Registering Language Profiles

A text service is only available when an application has the focus and the proper language is selected in the language bar. To facilitate this, TSF requires that a text service register itself for all of the languages that it supports. The text service registers its language profiles by calling ITfInputProcessorProfiles::AddLanguageProfile with the text service class identifier, that language identifier of the profile, and a text service defined GUID that identifies the language profile.

A language profile can be removed by calling ITfInputProcessorProfiles::RemoveLanguageProfile. ITfInputProcessorProfiles::Unregister removes all language profiles for the text service; when a text service is uninstalled, it does require removal of the individual language profiles.

Registering Categories

A text service must also register the category that the text service applies to. For example, if the text service supplies display attribute information, it must register itself as a display attribute provider by calling ITfCategoryMgr::RegisterCategory with the class identifier of the text service for the first parameter, GUID_TFCAT_DISPLAYATTRIBUTEPROVIDER for the second parameter and the class identifier of the text service again for the third parameter. The possible categories are listed under Predefined Category Values.

Remove previously registered categories by calling ITfCategoryMgr::UnregisterCategory. ITfInputProcessorProfiles::Unregister removes all categories for the text service; when a text service is uninstalled, it must remove the individual categories.