# Building an ASP.NET Core Backend Application to Host the Document Editor and Document Viewer
> This article explains how to create an ASP.NET Core backend application to host the Document Editor and Document Viewer. This backend application is required to provide the required functionality to the frontend applications built with Angular, React, or JavaScript.
- **Author:** Bjoern Meyer
- **Published:** 2024-03-14
- **Modified:** 2025-11-16
- **Description:** This article explains how to create an ASP.NET Core backend application to host the Document Editor and Document Viewer. This backend application is required to provide the required functionality to the frontend applications built with Angular, React, or JavaScript.
- **3 min read** (493 words)
- **Tags:**
- ASP.NET
- ASP.NET Core
- Angular
- React
- JavaScript
- Document Editor
- Document Viewer
- Backend
- **LLMs.txt URL:** https://www.textcontrol.com/blog/2024/03/14/building-an-asp-net-core-backend-application-to-host-the-document-editor-and-document-viewer/llms.txt
- **LLMs-full.txt URL:** https://www.textcontrol.com/blog/2024/03/14/building-an-asp-net-core-backend-application-to-host-the-document-editor-and-document-viewer/llms-full.txt
- **Canonical URL:** https://www.textcontrol.com/blog/2024/03/14/building-an-asp-net-core-backend-application-to-host-the-document-editor-and-document-viewer/
---
All [client-side packages](https://www.textcontrol.com/product/client-package/), including those for Angular, React, and JavaScript, require an ASP.NET Core backend application based on TX Text Control .NET Server to host the Document Editor and Document Viewer.
> **Prerequisites**
>
> In order to create a back-end application, you must have the TX Text Control .NET Server installed on your machine. You can download a trial version here.
>
> [Download Trial Version ](https://www.textcontrol.com/product/tx-text-control-dotnet-server/download/)
### Creating the Application
1. Open Visual Studio and create a new *ASP.NET Core Empty* application.
2. Select a project name, location and solution name in the next dialog and confirm with *Next*.
3. In the next dialog, choose *.NET 8 (Long Term Support)* as the *Framework* and confirm with *Create*.
### Adding the NuGet Packages
1. In the *Solution Explorer*, select your created project and choose *Manage NuGet Packages...* from the *Project* main menu.
Select *Text Control Offline Packages* from the *Package* source drop-down.
Install the latest versions of the following packages:
- **TXTextControl.TextControl.ASP.SDK**
- **TXTextControl.Web**
- **TXTextControl.Web.DocumentViewer**
2. Select *nuget.org* as the *Package* source and check for updates of the above packages. Update them if a newer package is available.
### Adding the Middleware
1. Open the *Program.cs* file located in the project's root folder. Replace the complete code with the following code:
```
using TXTextControl.Web;
using TXTextControl.Web.MVC.DocumentViewer;
var builder = WebApplication.CreateBuilder(args);
// adding CORS policy to allow all origins
builder.Services.AddCors(options =>
{
options.AddDefaultPolicy(
builder =>
{
builder.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader();
});
});
// adding controllers for DocumentViewer Web API
builder.Services.AddControllers();
var app = builder.Build();
app.MapGet("/", () => "TX Text Control .NET Server for ASP.NET Backend is up and running!");
app.UseRouting();
// adding CORS middleware
app.UseCors();
// adding WebSockets middleware
app.UseWebSockets();
// adding TX Text Control middleware
app.UseTXWebSocketMiddleware();
app.UseTXDocumentViewer();
app.Run();
```
### Running the Backend
1. Press *F5* to start the application.
After launching the application, you should see the following screen.
### Connecting Client-Site Packages
The Document Editor and Document Viewer instances used in your Angular, React, or JavaScript applications can now be connected to your newly created backend.
#### Document Editor
In your Angular, React, or JavaScript project, change the *webSocketURL* attribute of the Document Editor component in the to the URL of your backend application created above. For example in Angular:
```
```
Make sure that *wss* is used if the backend is hosted using https and that *ws* is used in the case of http.
#### Document Viewer
In your Angular, React, or JavaScript project, change the *basePath* attribute of the Document Viewer component in the to the URL of your backend application created above. For example in Angular:
```
```
---
## About Bjoern Meyer
As CEO, Bjoern is the visionary behind our strategic direction and business development, bridging the gap between our customers and engineering teams. His deep passion for coding and web technologies drives the creation of innovative products. If you're at a tech conference, be sure to stop by our booth - you'll most likely meet Bjoern in person. With an advanced graduate degree (Dipl. Inf.) in Computer Science, specializing in AI, from the University of Bremen, Bjoern brings significant expertise to his role. In his spare time, Bjoern enjoys running, paragliding, mountain biking, and playing the piano.
- [LinkedIn](https://www.linkedin.com/in/bjoernmeyer/)
- [X](https://x.com/txbjoern)
- [GitHub](https://github.com/bjoerntx)
---
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