Chat with Your Own Data

• Sep 29, 2025
• 5 minutes to read

When integrating the AI Chat Control with the OpenAI Assistant API, you can configure it to retain and reference a specific context (for example, a text file or a PDF document). By providing a supplementary document as a context source, the assistant is primed with background information. OpenAI automatically parses the document and searches through it to retrieve relevant content to better respond to user queries.

1. Install the DevExpress.AIIntegration.OpenAI NuGet package.

2. Create an assistant.

   C#

   using OpenAI;
   using OpenAI.Assistants;
   using OpenAI.Files;
   using System.IO;
   using System.ClientModel;
   using System.Threading.Tasks;
   using System.Threading;
   using System;
   
   #pragma warning disable OPENAI001
   public class OpenAIAssistantCreator {
       readonly AssistantClient assistantClient;
       readonly OpenAIFileClient fileClient;
       readonly string deployment;
   
       public OpenAIAssistantCreator(OpenAIClient client, string deployment) {
           assistantClient = client.GetAssistantClient();
           fileClient = client.GetOpenAIFileClient();
           this.deployment = deployment;
       }
   
       public async Task<string> CreateAssistantAsync(
               Stream data,
               string fileName,
               string instructions,
               bool useFileSearchTool = true,
               CancellationToken ct = default) {
   
           data.Position = 0;
   
           ClientResult<OpenAIFile> fileResponse = await fileClient.UploadFileAsync(data, fileName, FileUploadPurpose.Assistants, ct);
           OpenAIFile file = fileResponse.Value;
   
           var resources = new ToolResources() {
               CodeInterpreter = new CodeInterpreterToolResources(),
               FileSearch = useFileSearchTool ? new FileSearchToolResources() : null
           };
           resources.FileSearch?.NewVectorStores.Add(new VectorStoreCreationHelper([file.Id]));
           resources.CodeInterpreter.FileIds.Add(file.Id);
   
           AssistantCreationOptions assistantCreationOptions = new AssistantCreationOptions() {
               Name = Guid.NewGuid().ToString(),
               Instructions = instructions,
               ToolResources = resources
           };
   
           assistantCreationOptions.Tools.Add(new CodeInterpreterToolDefinition());
           if (useFileSearchTool) {
               assistantCreationOptions.Tools.Add(new FileSearchToolDefinition());
           }
   
           ClientResult<Assistant> assistantResponse = await assistantClient.CreateAssistantAsync(deployment, assistantCreationOptions, ct);
           Assistant assistant = assistantResponse.Value;
   
           return assistant.Id;
       }
   }
   #pragma warning restore OPENAI001
   

   VB.NET

   Imports OpenAI
   Imports OpenAI.Assistants
   Imports OpenAI.Files
   Imports System.IO
   Imports System.Threading.Tasks
   Imports System.Threading
   Imports System
   
   #Disable Warning OPENAI001
   Public Class OpenAIAssistantCreator
       Private ReadOnly assistantClient As AssistantClient
       Private ReadOnly fileClient As OpenAIFileClient
       Private ReadOnly deployment As String
   
       Public Sub New(client As OpenAIClient, deployment As String)
           assistantClient = client.GetAssistantClient()
           fileClient = client.GetOpenAIFileClient()
           Me.deployment = deployment
       End Sub
   
       Public Async Function CreateAssistantAsync(data As Stream, fileName As String, instructions As String, Optional useFileSearchTool As Boolean = True, Optional ct As CancellationToken = Nothing) As Task(Of String)
           data.Position = 0
   
           Dim fileResponse As ClientResult(Of OpenAIFile) = Await fileClient.UploadFileAsync(data, fileName, FileUploadPurpose.Assistants, ct)
           Dim file As OpenAIFile = fileResponse.Value
   
           Dim resources As New ToolResources() With {
               .CodeInterpreter = New CodeInterpreterToolResources(),
               .FileSearch = If(useFileSearchTool, New FileSearchToolResources(), Nothing)
           }
           If resources.FileSearch IsNot Nothing Then
               resources.FileSearch.NewVectorStores.Add(New VectorStoreCreationHelper({file.Id}))
           End If
           resources.CodeInterpreter.FileIds.Add(file.Id)
   
           Dim assistantCreationOptions As New AssistantCreationOptions() With {
               .Name = Guid.NewGuid().ToString(),
               .Instructions = instructions,
               .ToolResources = resources
           }
   
           assistantCreationOptions.Tools.Add(New CodeInterpreterToolDefinition())
           If useFileSearchTool Then
               assistantCreationOptions.Tools.Add(New FileSearchToolDefinition())
           End If
   
           Dim assistantResponse As ClientResult(Of Assistant) = Await assistantClient.CreateAssistantAsync(deployment, assistantCreationOptions, ct)
           Dim assistant As Assistant = assistantResponse.Value
   
           Return assistant.Id
       End Function
   End Class
   #Enable Warning OPENAI001
   

   Warning

   The OpenAI.OpenAIClient API is for evaluation purposes only and is subject to change or removal in a future update. The following code snippet suppresses the OPENAI001 diagnostic:

3. Register the OpenAI Assistant service:

   Program.cs

   using Azure.AI.OpenAI;
   using System.Windows.Forms;
   using System.ClientModel;
   using DevExpress.AIIntegration;
   using Microsoft.Extensions.AI;
   
   namespace AIChat {
       internal static class Program {
           [STAThread]
           static void Main() {
               Application.EnableVisualStyles();
               Application.SetCompatibleTextRenderingDefault(false);
   
               var azureOpenAiClient = new Azure.AI.OpenAI.AzureOpenAIClient(AzureOpenAIEndpoint, AzureOpenAIKey);
   
               var container = AIExtensionsContainerDesktop.Default;
               container.RegisterChatClient(azureOpenAiClient.GetChatClient(ModelId).AsIChatClient());
               container.RegisterOpenAIAssistants(azureOpenAiClient, ModelId); // For example, ModelId = "gpt-4o-mini"
   
               Application.Run(new ChatForm(new OpenAIAssistantCreator(azureChatClient, ModelId)));
           }
           private static Uri AzureOpenAIEndpoint = new Uri("YOUR_AZURE_OPENAI_ENDPOINT");
           private static ApiKeyCredential AzureOpenAIKey = new ApiKeyCredential("YOUR_AZURE_OPENAI_KEY");
       }
   }
   

   Program.vb

   Imports Azure.AI.OpenAI
   Imports System.Windows.Forms
   Imports System.ClientModel
   Imports DevExpress.AIIntegration
   Imports Microsoft.Extensions.AI
   
   Namespace AIChat
       Friend Module Program
           <STAThread>
           Sub Main()
               Application.EnableVisualStyles()
               Application.SetCompatibleTextRenderingDefault(False)
   
               Dim azureOpenAiClient = New AzureOpenAIClient(AzureOpenAIEndpoint, AzureOpenAIKey)
   
               Dim container = AIExtensionsContainerDesktop.Default
               container.RegisterChatClient(azureOpenAiClient.GetChatClient(ModelId).AsIChatClient())
               container.RegisterOpenAIAssistants(azureOpenAiClient, ModelId) ' For example, ModelId = "gpt-4o-mini"
   
               Application.Run(New ChatForm(New OpenAIAssistantCreator(azureOpenAiClient, ModelId)))
           End Sub
   
           Private ReadOnly AzureOpenAIEndpoint As New Uri("YOUR_AZURE_OPENAI_ENDPOINT")
           Private ReadOnly AzureOpenAIKey As New ApiKeyCredential("YOUR_AZURE_OPENAI_KEY")
       End Module
   End Namespace
   

   Note

   The availability of Azure Open AI Assistants depends on the region. Refer to the following article for more information: Assistants (Preview).

4. Handle the Initialized event with an async handler. Call the e.SetupAssistantAsync method to supply the Open AI Assistant identifier:

   C#

   using System.IO;
   using DevExpress.AIIntegration.Blazor.Chat.WebView;
   
   public partial class ChatForm : XtraForm {
       FileStream dataStream;
       readonly OpenAIAssistantCreator _openAIAssistantCreator;
   
       public ChatForm(OpenAIAssistantCreator openAIAssistantCreator) {
           InitializeComponent();
           _openAIAssistantCreator = openAIAssistantCreator;
           dataStream = File.OpenRead(@"RestaurantMenu.pdf");
           /*
            * In this example, aiChatControl1 was created and configured at design time.
            */
           aiChatControl1.Initialized += AiChatControl1_Initialized;
       }
       async void AiChatControl1_Initialized(object sender, AIChatControlInitializedEventArgs e) {
           string fileName = "RestaurantMenu.pdf";
           string prompt = "You are an Analyst Assistant specializing in PDF file analysis. Your role is to assist users by providing accurate answers to their questions about data contained in these files.";
           string assistantID = await _openAIAssistantCreator.CreateAssistantAsync(dataStream, fileName, prompt);
           await e.SetupAssistantAsync(assistantID); 
       }
   }
   

   VB.NET

   Imports System.IO
   Imports DevExpress.AIIntegration.Blazor.Chat.WebView
   
   Public Partial Class ChatForm
       Inherits XtraForm
   
       Private dataStream As FileStream
       Private ReadOnly _openAIAssistantCreator As OpenAIAssistantCreator
   
       Public Sub New(openAIAssistantCreator As OpenAIAssistantCreator)
           InitializeComponent()
           _openAIAssistantCreator = openAIAssistantCreator
           dataStream = File.OpenRead("RestaurantMenu.pdf")
           '
           ' In this example, aiChatControl1 was created and configured at design time.
           '
           AddHandler aiChatControl1.Initialized, AddressOf AiChatControl1_Initialized
       End Sub
   
       Private Async Sub AiChatControl1_Initialized(sender As Object, e As AIChatControlInitializedEventArgs)
           Dim fileName As String = "RestaurantMenu.pdf"
           Dim prompt As String = "You are an Analyst Assistant specializing in PDF file analysis. Your role is to assist users by providing accurate answers to their questions about data contained in these files."
           Dim assistantID As String = Await _openAIAssistantCreator.CreateAssistantAsync(dataStream, fileName, prompt)
           Await e.SetupAssistantAsync(assistantID)
       End Sub
   End Class
   

The following screenshot shows the result:

Tip

The AI Chat Control does not render citation references as clickable links. These references appear as plain text (for example, [6:2†source]) in the output. To remove citation references from the AI response before display, handle the AI Chat Control’s MarkdownConvert event:

using Markdig;
using System.Text.RegularExpressions;

void AiChatControl1_MarkdownConvert(object sender, AIChatControlMarkdownConvertEventArgs e) {
    string output = ClearCitationReferences(e.MarkdownText);
    e.HtmlText = (MarkupString)Markdown.ToHtml(output);
}

string ClearCitationReferences(string text) {
    return Regex.Replace(text, @"\【.*?】", "");
}