Products Technologies Demo Docs Blog Support Company

How to Manipulate the Document using the WebSocketHandler

The WebSocketHandler acts as a proxy between the client-side JavaScript and the TCP synchronization service. However, the WebSocketHandler can be used directly on the server side to do document manipulation.

How to Manipulate the Document using the WebSocketHandler

As of 32.0 SP1, the Document Editor has the new JavaScript property connectionID that returns the unique ID of the WebSocket connection. The WebSocketHandler acts as a proxy between the client-side JavaScript and the TCP synchronization service. This id is used for communication between the editor and the server-side WebSocketHandler for document rendering synchronization.

Now that this ID is publicly available, you can use it to connect to the document instance on the server side and manipulate the document directly in the WebSocketHandler in server-side C# code.

The following JavaScript code shows how to retrieve the connection ID and store it globally.

var connectionID;

 TXTextControl.addEventListener("textControlLoaded", function () {
     connectionID = TXTextControl.connectionID;
 });

Loading Documents

In the first example, a document is loaded directly from the server using the WebSocketHandler. The example consists of a button that calls the loadDocument function.

@using TXTextControl.Web.MVC

@Html.TXTextControl().TextControl().Render()

<input type="button" onclick="loadDocument()" value="Load Document" />

<script>

    var connectionID;

    TXTextControl.addEventListener("textControlLoaded", function () {
        connectionID = TXTextControl.connectionID;
    });

    function loadDocument() {
      $.ajax({
              url: '@Url.Action("LoadDocument")',
              type: 'POST',
              data: { connectionID: connectionID },
      });
    }
    
</script>

The method posts the connection ID to the LoadDocument endpoint. The GetInstance method of the WebSocketHandler returns the instance specified by the connection id. The LoadText method is then used to load the document directly into the instance.

[HttpPost]
public HttpResponseMessage LoadDocument(string ConnectionID)
{
        // connect the WebSocketHandler with the ConnectionID
        WebSocketHandler wsHandler = WebSocketHandler.GetInstance(ConnectionID);

        // the document directly server-side
        wsHandler.LoadText("App_Data/demo.tx", StreamType.InternalUnicodeFormat);

        return new HttpResponseMessage()
        {
                StatusCode = HttpStatusCode.OK
        };
}

Direct loading of a document is shown in the following screen video.

Loading using WebSocketHandler

Complex Formatting

For complex formatting tasks, the JavaScript API may be too slow (callbacks). In the following example, we want to highlight the keyword TextControl in a selected area of text.

Formatting using WebSocketHandler

The doComplexFormatting function calls the DoComplexFormatting server-side method. Before the Http POST method is called, the editor is set to read-only, and upon successful execution, the editor is set back to edit mode.

@using TXTextControl.Web.MVC

@Html.TXTextControl().TextControl().Render()

input type="button" onclick="doComplexFormatting()" value="Complex Formatting" />

<script>

    var connectionID;

    TXTextControl.addEventListener("textControlLoaded", function () {
        connectionID = TXTextControl.connectionID;
    });

    function doComplexFormatting() {

        TXTextControl.editMode = TXTextControl.EditMode.ReadOnly;

        $.ajax({
            url: '@Url.Action("DoComplexFormatting")',
            type: 'POST',
            data: { connectionID: connectionID },
            success: function (data) {
                TXTextControl.editMode = TXTextControl.EditMode.Edit;
            }
        });
    }
</script>

The selection is loaded into a temporary ServerTextControl for manipulation. Found keywords are highlighted in a loop before the selection is saved and loaded back into the editor.

[HttpPost]
public HttpResponseMessage DoComplexFormatting(string ConnectionID)
{
    // connect the WebSocketHandler with the ConnectionID
    WebSocketHandler wsHandler = WebSocketHandler.GetInstance(ConnectionID);

    byte[] data;

    // save the current selection to a byte array
    wsHandler.Selection.Save(out data, BinaryStreamType.InternalUnicodeFormat);

    // load the byte array into a ServerTextControl
    using (TXTextControl.ServerTextControl tx = new TXTextControl.ServerTextControl())
    {
        tx.Create();
        tx.Load(data, TXTextControl.BinaryStreamType.InternalUnicodeFormat);

        // loop through all words and format the word "TextControl"
        for (int i = 0; i < tx.Text.Length; i++)
        {
            tx.Select(i, 1);
            tx.SelectWord();

            if (tx.Selection.Text == "TextControl")
            {
                tx.Selection.Bold = true;
                tx.Selection.Italic = true;
                tx.Selection.ForeColor = Color.Red;

                i += tx.Selection.Text.Length;
            }
        }

        // save the document to a byte array and load it into the WebSocketHandler
        tx.Save(out data, TXTextControl.BinaryStreamType.InternalUnicodeFormat);
        wsHandler.Selection.Load(data, BinaryStreamType.InternalUnicodeFormat);
    }

    return new HttpResponseMessage()
    {
        StatusCode = HttpStatusCode.OK
    };
}

Conclusion

The WebSocketHandler can be used to directly manipulate the document on the server side using C# code. This is a very sufficient way to edit documents, especially for complex formatting tasks.

Stay in the loop!

Subscribe to the newsletter to receive the latest updates.

ASP.NET

Integrate document processing into your applications to create documents such as PDFs and MS Word documents, including client-side document editing, viewing, and electronic signatures.

ASP.NET Core
Angular
Blazor
JavaScript
React
  • Angular
  • Blazor
  • React
  • JavaScript
  • ASP.NET MVC, ASP.NET Core, and WebForms

Learn more Trial token Download trial

Related Posts

ASP.NETAIASP.NET Core

AI Natural Language Document Generation with MCP and TX Text Control .NET

This article explains how AI agents can use natural language to create documents through an MCP server. Instead of letting a language model generate documents directly, the AI translates prompts…


ASP.NETASP.NET CoreConference

WeAreDevelopers World Congress Europe 2026 Wrap Up: Record Breaking Days in…

WeAreDevelopers World Congress Europe 2026 was a record-breaking event in Berlin, bringing together over 15,000 developers and tech enthusiasts from around the world. The conference featured…


ASP.NETReportingASP.NET Core

C# Document Generation: A Developer's Guide for .NET

Document generation refers to the automatic creation of documents from application data. The success or complexity of a document generation workflow often depends on a single early architectural…


ASP.NETAccessibilityASP.NET Core

Validating PDF/UA Documents in .NET C#: A Practical Guide

This article explains how to validate PDF/UA documents in .NET C# using the TXTextControl.PDF.Validation NuGet package. It shows how to inspect validation status, generate JSON reports, handle…


ASP.NETASP.NET CoreConferences

See Text Control at WeAreDevelopers World Congress Europe 2026 in Berlin

WeAreDevelopers World Congress Europe 2026 is the largest developer conference in Europe. Text Control will be there to showcase our latest products and features. Join us in Berlin from July 9-10,…

Share on this blog post on: