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

Install the CData ADO.NET Provider for Excel Online

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

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

Create a Excel Online-Connected Blazor App

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

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

SELECT Excel Online Data from the Blazor App

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

   You can connect to a workbook by providing authentication to Excel Online and then setting the following properties:

   • Workbook: Set this to the name or Id of the workbook.

     If you want to view a list of information about the available workbooks, execute a query to the Workbooks view after you authenticate.

   • UseSandbox: Set this to true if you are connecting to a workbook in a sandbox account. Otherwise, leave this blank to connect to a production account.

   You use the OAuth authentication standard to authenticate to Excel Online. See the Getting Started section in the help documentation for a guide. Getting Started also guides you through executing SQL to worksheets and ranges.

   For example:

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

         @page "/"
         @using System.Data;
         @using System.Data.CData.ExcelOnline;
         
         <h1>Hello, world!</h1>
         
         Welcome to your Data app.
         
         <div class="row">
             <div class="col-12">
         
                 @using (ExcelOnlineConnection connection = new ExcelOnlineConnection(
                   ""))
                 {
                     var sql = "SELECT Id, Column1 FROM Test_xlsx_Sheet1";
                     var results = new DataTable();
         
                     ExcelOnlineDataAdapter dataAdapter = new ExcelOnlineDataAdapter(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 Excel Online data as an HTML table in the Blazor app.

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