How to filter search results for documents dynamically by the folder name?

The solution applies for Sitefinity version 14.4 and later.

Overview of the sample:

This sample will extend the built-in search functionality and add filters to the search results widget in Sitefinity.

The final output looks like:

A dropdown is added to the search results widget with filtering options. The filter options are used to filter the results for searching for documents. A document library contains a set of folders and inside them documents (refer to screenshot below)

The new functionality will list "folder1 and folder2" as options with which to filter search results.

Steps to add this customization:

Step 1: Setup of Sitefinity search

1. 1. Go to Administration -> Search and Indexes module and create a search index
   2. Edit the search index and in Advanced settings -> Additional fields for indexing add "FolderId"

       3. Go to Content -> Documents & Files module and create new document library named: SourceLibrary

       and inside it add two folders: folder1 and folder2. Upload documents to each folder.

Step 2: Create a widget displaying the search filter

To filter search results the filter options need to be displayed on a page so a Sitefinity widget needs to be created to do this.

The aim of the widget is to render folder1 and folder2 (or any other Sitefinity data can be used for filtering)

Refer to the attached files to this article. Download the attachments and place folder Mvc in the Sitefinity site solution using Visual Studio. Refer to the screenshot below:

Those are the files for a Sitefinity widget rendering folder1 and folder2 (or if more folders are present, it will list all).

Add the widget to a page, it is created under CustomWidgets section in page toolbox.

Add Search results and Search box widgets as well to a page in order to have Sitefinity search functionality established.

Step 3: Customize the built-in Sitefinity search widget to respect the filtering options listed in Library Dropbox widget.

Additional sample in  Search: Override MVC Search results widget

From the attached files include Global.asax.cs and CustomSearchResultsModel.cs and include them in the Visual Studio solution for the site.

Code walkthrough: 

Use the onchange event of the drop box and add the selected folder id to the "filter" query string parameter (it has to be base64 encoded). (this is done in the index.js)

(Attached are the files of the widget - LibraryDropboxController.cs, LibraryDropboxModel.cs, LibraryDropboxViewModel.cs, index.cshtml, index.js)

Extend SearchResultsModel (CustomSearchResultsModel.cs file):

- Override the PopulateResults method - when the method is called, the added filter value in the query string (from previous step) will come as an input for the filter parameter.

- in the SearchCustom method which is called by the PopulateResults - create new SearchFilter with a clause to filter by the field FolderId and add the filter to the searchParameters.

In Global.asax.cs register the custom search results to replace the built-in one by adding:

protected void Application_Start(object sender, EventArgs e)
{
    Bootstrapper.Bootstrapped += this.Bootstrapper_Bootstrapped;
}

private void Bootstrapper_Bootstrapped(object sender, EventArgs e)
{
    FrontendModule.Current.DependencyResolver.Rebind<ISearchResultsModel>().To<SearchResultsModelCustom>();
}