# Using ServerTextControl in Desktop Applications > Use ServerTextControl beside the Windows Forms editor: create and dispose it, pass documents as byte arrays, merge letters and license it in a class library. - **Product:** TX Text Control .NET for Windows Forms - **Section:** Documentation - **Kind:** Topic - **Path:** TX Text Control .NET for Windows Forms > Document Processing > Using ServerTextControl in Desktop Applications - **2351 words** - **Web URL:** https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-processing/servertextcontrol/ - **LLMs URL:** https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-processing/servertextcontrol/llms.txt - **LLMs-Full URL:** https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-processing/servertextcontrol/llms-full.txt --- The `TextControl` on a form is the document the user works on. Everything else your application does with documents, such as merging letters, converting a folder to PDF or preparing a document before the user sees it, belongs in a `ServerTextControl`: the same document engine and programming interface, without a window. Used this way, the editor keeps its document and its undo history, and long work can run on a background thread while the form stays responsive. [ServerTextControl](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/overview/components/servertextcontrol/llms-full.txt) in the Overview introduces the component. The examples below are handlers in *Form1.cs* with the `TextControl` named `textControl1`, and *Form1.cs* needs these `using` directives: ```csharp using System.IO; using TXTextControl; ``` ### When to Use ServerTextControl | Task | Use | |---|---| | The user edits, formats or reads a document | `TextControl` | | Build or merge a document before the user sees it | `ServerTextControl`, then load the result into the `TextControl` | | Convert, merge or print files the user doesn't see | `ServerTextControl` | | Work that takes longer than a moment | `ServerTextControl` on a background thread | A [ServerTextControl](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol/servertextcontrol/llms-full.txt) is a component without a window that has the document members of the `TextControl`; [What ServerTextControl Is](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/overview/components/servertextcontrol/#what-servertextcontrol-is) describes the class and why it is faster and smaller for the same work. ### Create and Dispose Each Instance Every use of a `ServerTextControl` follows the same pattern: ```csharp private void createDocumentButton_Click(object sender, EventArgs e) { using (ServerTextControl tx = new ServerTextControl()) { // Initialize the new instance before using any other member if (!tx.Create()) { MessageBox.Show("TX Text Control could not be initialized."); return; } tx.Text = "Thank you for your order."; tx.Save("confirmation.docx", StreamType.WordprocessingML); } } ``` - [Create](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol/servertextcontrol/create-method/llms-full.txt) initializes the resources of the instance and must be called first. It returns `false` if the instance couldn't be initialized. - The `using` block disposes the instance at its end, which releases its resources. [Memory Usage and Resource Disposal](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/performance/memory-usage/llms-full.txt) describes what happens to instances that are never disposed. Create one instance for each piece of work, and don't keep instances in fields of the form for later use. ### Move Documents Between the Editor and ServerTextControl Both classes load and save byte arrays, so a document moves between them without a file. [BinaryStreamType](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol/binarystreamtype/enumeration/llms-full.txt) `InternalUnicodeFormat`, the TX Text Control format, keeps everything the document contains. The following handler builds a letter in a `ServerTextControl` and shows it in the editor: ```csharp private void showLetterButton_Click(object sender, EventArgs e) { byte[] document; using (ServerTextControl tx = new ServerTextControl()) { tx.Create(); tx.Selection.FontSize = 280; // 14 points, in twips tx.Selection.Text = "Order Confirmation\r\n"; tx.Selection.FontSize = 220; tx.Selection.Text = "Thank you for your order."; tx.Save(out document, BinaryStreamType.InternalUnicodeFormat); } // Replace the document of the editor textControl1.Load(document, BinaryStreamType.InternalUnicodeFormat); } ``` The other direction works the same way: `textControl1.Save(out byte[] data, BinaryStreamType.InternalUnicodeFormat)` hands the editor's document to a `ServerTextControl`, for example to convert or print it in the background. [TextControl.Load](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol/textcontrol/load-method/llms-full.txt) replaces the document of the editor; [TextControl.Append](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol/textcontrol/append-method/llms-full.txt) adds a document at its end instead. [Selection.FontSize](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol/selection/fontsize-property/llms-full.txt) is set in twips, 20 per point. ### Work in the Background `Load`, `Save` and the merge methods have no asynchronous versions: they occupy the thread that calls them until they return, so called in a button handler, they block the form. A `ServerTextControl` can run on another thread: run long work with `Task.Run`, give each thread its own instance, and keep the `TextControl`, which belongs to the UI thread, out of it. To process the editor's document in the background, save it to a byte array on the UI thread, as shown above, and pass the array to the task. [UI Threading and Background Operations](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/performance/threading/llms-full.txt) shows these rules in code: it exports the editor's document in the background, brings a result back to the editor, converts a folder of files with progress and cancel, and explains why more threads don't make document processing proportionally faster. [Printing](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-processing/printing/#print-without-blocking-the-form) prints in the background the same way. ### Merge Templates Without the Editor A [MailMerge](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol-documentserver/mailmerge/llms-full.txt) works with the text component it is connected through [TextComponent](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol-documentserver/mailmerge/textcomponent-property/llms-full.txt). Connected to a `ServerTextControl`, it creates documents while the editor shows something else; the result can then be saved, printed or loaded into the editor: ```csharp private void mergeButton_Click(object sender, EventArgs e) { string jsonData = File.ReadAllText("customers.json"); byte[] result; using (ServerTextControl tx = new ServerTextControl()) { tx.Create(); TXTextControl.DocumentServer.MailMerge mailMerge = new TXTextControl.DocumentServer.MailMerge(); mailMerge.TextComponent = tx; mailMerge.LoadTemplate("letter-template.docx", TXTextControl.DocumentServer.FileFormat.WordprocessingML); mailMerge.MergeJsonData(jsonData); tx.Save(out result, BinaryStreamType.InternalUnicodeFormat); } textControl1.Load(result, BinaryStreamType.InternalUnicodeFormat); } ``` [Mail Merge and Reporting](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/mail-merge/llms-full.txt) describes templates, data and merge settings. ### License ServerTextControl in a Class Library `ServerTextControl` is covered by the license of TX Text Control .NET for Windows Forms and needs no server license. When it is used in a class library rather than in the executable of the application, the static property [ServerTextControl.EntryAssembly](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/reference/txtextcontrol/servertextcontrol/entryassembly-property/llms-full.txt) names the assembly that holds the license. [Class Libraries and User Controls](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/installation/licensing/application/#class-libraries-and-user-controls) shows a class library that sets it and lists the versions that support it. ### Next Steps - [Creating Documents](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-processing/creating/llms-full.txt): build documents in code. - [Saving and Converting Documents](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-processing/saving-converting/llms-full.txt): the formats `Save` writes. - [UI Threading and Background Operations](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/performance/threading/llms-full.txt): threads in a Windows Forms application. - [Mail Merge and Reporting](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/mail-merge/llms-full.txt): create documents from templates and data. --- ## Nearby - **Previous:** [Printing](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-processing/printing/llms-full.txt) - **Next:** [Exceptions and Error Handling](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-processing/exceptions/llms-full.txt)