Connect to Foursquare Data from Blazor Apps

Blazor is a framework for developing modern, client-side web UIs using .NET technology. Instead of coding in JavaScript, developers can use the familiar C# language and .NET libraries to build app UIs.

The CData API Driver for ADO.NET can be used with standard ADO.NET interfaces, such as LINQ and Entity Framework, to interact with live Foursquare data. Since Blazor supports .NET Core, developers can use CData ADO.NET Providers in Blazor apps. In this article, we will guide you to build a simple Blazor app that talks to Foursquare using standard SQL queries.

Install the CData API Driver for ADO.NET

CData ADO.NET Providers allow users to access Foursquare just like they would access SQL Server, using simple SQL queries.

Install the Foursquare ADO.NET Data Provider from the CData website or from NuGet. Search NuGet for "Foursquare ADO.NET Data Provider."

Create a Foursquare-Connected Blazor App

Start by creating a Blazor project that references the CData API Driver for ADO.NET

1. Create a Blazor project on Visual Studio.

2. From the Solution Explorer, right click Dependencies, then click Add Project Reference.
3. In the Reference Manager, click the Browse button, and choose the .dll file of the installed ADO.NET Provider (e.g. System.Data.CData.API.dll, typically located at C:\Program Files\CData\CData API Driver for ADO.NET\lib etstandard2.0).

SELECT Foursquare Data from the Blazor App

1. Open the Index.razor file from the Project page.
2. In a APIConnection object, set the connection string:

   Using API Key Authentication

   Foursquare Places API uses Service Key (Bearer token) authentication. To obtain a Service Key:

   1. Go to the Foursquare Developer Console at https://foursquare.com/developers/
   2. Create a new project or select an existing one
   3. Navigate to the API Keys section
   4. Generate a new Service Key for the Places API

   After setting the following connection properties, you are ready to connect:

   • AuthScheme: Set this to APIKey.
   • ServiceKey: Set this to your Foursquare Service Key obtained from the Developer Console.
   • XPlacesApiVersion: (Optional) Set this to the API version date. Defaults to 2025-06-17.

   Example APIKey connection string

   Profile=C:\profiles\Foursquare.apip;AuthScheme=APIKey;ProfileSettings='APIKey=your_personal_access_token';
   

   For example: Profile=C:\profiles\Foursquare.apip;AuthScheme=APIKey;ProfileSettings='APIKey=your_personal_access_token';

3. The code below creates a simple Blazor app for displaying Foursquare data, using standard SQL to query Foursquare just like SQL Server.

         @page "/"
         @using System.Data;
         @using System.Data.CData.API;
         
         <h1>Hello, world!</h1>
         
         Welcome to your Data app.
         
         <div class="row">
             <div class="col-12">
         
                 @using (APIConnection connection = new APIConnection(
                   "Profile=C:\profiles\Foursquare.apip;AuthScheme=APIKey;ProfileSettings='APIKey=your_personal_access_token';"))
                 {
                     var sql = "SELECT ,  FROM Autocomplete WHERE Query = 'abc'";
                     var results = new DataTable();
         
                     APIDataAdapter dataAdapter = new APIDataAdapter(sql, connection);
                     dataAdapter.Fill(results);
         
                     <table class="table table-bordered">
                         <thead class="thead-light">
                             <tr>
                                 @foreach (DataColumn item in results.Rows[0].Table.Columns)
                                 {
                                     <th scope="col">@item.ColumnName</th>
                                 }
                             </tr>
                         </thead>
                         <tbody>
                             @foreach (DataRow row in results.Rows)
                             {
                                 <tr>
                                     @foreach (var column in row.ItemArray)
                                     {
                                         <td>@column.ToString()</td>
                                     }
                                 </tr>
                             }
                         </tbody>
                     </table>
                 }
             </div>
         </div>
       

4. Rebuild and run the project. The ADO.NET Provider renders Foursquare data as an HTML table in the Blazor app.

   At this point, you have a Foursquare-connected Blazor app, capable of working with live Foursquare data just like you would work with a SQL Server instance. Download a free, 30-day trial and start working with live Foursquare data in your Blazor apps today.