Connect to REST 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 ADO.NET Provider for REST can be used with standard ADO.NET interfaces, such as LINQ and Entity Framework, to interact with live REST 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 REST using standard SQL queries.

Install the CData ADO.NET Provider for REST

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

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

Create a REST-Connected Blazor App

Start by creating a Blazor project that references the CData ADO.NET Provider for REST

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.REST.dll, typically located at C:\Program Files\CData\CData ADO.NET Provider for REST\lib etstandard2.0).

SELECT REST Data from the Blazor App

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

   See the Getting Started chapter in the data provider documentation to authenticate to your data source: The data provider models REST APIs as bidirectional database tables and XML/JSON files as read-only views (local files, files stored on popular cloud services, and FTP servers). The major authentication schemes are supported, including HTTP Basic, Digest, NTLM, OAuth, and FTP. See the Getting Started chapter in the data provider documentation for authentication guides.

   After setting the URI and providing any authentication values, set Format to "XML" or "JSON" and set DataModel to more closely match the data representation to the structure of your data.

   The DataModel property is the controlling property over how your data is represented into tables and toggles the following basic configurations.

   • Document (default): Model a top-level, document view of your REST data. The data provider returns nested elements as aggregates of data.
   • FlattenedDocuments: Implicitly join nested documents and their parents into a single table.
   • Relational: Return individual, related tables from hierarchical data. The tables contain a primary key and a foreign key that links to the parent document.

   See the Modeling REST Data chapter for more information on configuring the relational representation. You will also find the sample data used in the following examples. The data includes entries for people, the cars they own, and various maintenance services performed on those cars.

   For example: DataModel=Relational;URI=C:/people.xml;Format=XML;

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

         @page "/"
         @using System.Data;
         @using System.Data.CData.REST;
         
         <h1>Hello, world!</h1>
         
         Welcome to your Data app.
         
         <div class="row">
             <div class="col-12">
         
                 @using (RESTConnection connection = new RESTConnection(
                   "DataModel=Relational;URI=C:/people.xml;Format=XML;"))
                 {
                     var sql = "SELECT [people].[personal.age] AS age, [people].[personal.gender] AS gender, [people].[personal.name.first] AS first_name, [people].[personal.name.last] AS last_name, [vehicles].[model], FROM [people] JOIN [vehicles] ON [people].[_id] = [vehicles].[people_id]";
                     var results = new DataTable();
         
                     RESTDataAdapter dataAdapter = new RESTDataAdapter(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 REST data as an HTML table in the Blazor app.

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