.NET MAUI - Simple Chat Client

Browse code

A minimal .NET MAUI sample that wires Microsoft.Extensions.AI into a chat UI. It registers an IChatClient via a Host Builder extension using Azure AI Foundry (OpenAI-compatible) and demonstrates MVVM command binding, a CollectionView EmptyView, and a simple "typing" placeholder while awaiting responses.

What you'll learn

• How to register and consume IChatClient (Microsoft.Extensions.AI) with DI in a MAUI app
• How to configure Azure AI Foundry/OpenAI-compatible endpoints using environment variables
• How to drive a chat UI with MVVM (CommunityToolkit.Mvvm) and update the UI as responses arrive
• How to use a CollectionView EmptyView for a “first-run” prompt experience

Prerequisites

• .NET SDK compatible with the repo branch (Windows desktop build shown)
• Azure AI Foundry (or Azure OpenAI) endpoint and API key — see Set up: retrieve key and endpoint

Configure (desktop; environment variables)

Set these variables for your user profile so the app can connect to your Foundry/OpenAI-compatible endpoint:

• AZURE_OPENAI_ENDPOINT (required) — for example https://your-endpoint
• AZURE_OPENAI_API_KEY (required)
• AZURE_OPENAI_MODEL (optional; defaults to gpt-4o-mini)

PowerShell (per-user, persistent):

[System.Environment]::SetEnvironmentVariable('AZURE_OPENAI_ENDPOINT','https://your-endpoint','User')
[System.Environment]::SetEnvironmentVariable('AZURE_OPENAI_API_KEY','your-api-key','User')
# Optional
[System.Environment]::SetEnvironmentVariable('AZURE_OPENAI_MODEL','gpt-4o-mini','User')

Restart your IDE/terminal after setting variables.

How it’s wired

• Services/HostingExtensions.cs: Adds AddFoundryChatClient(), reading environment variables and registering a singleton IChatClient backed by AzureOpenAIClient.
• MauiProgram.cs: On Windows, calls AddFoundryChatClient() and registers ChatViewModel.
• ViewModels/ChatViewModel.cs: Injects IChatClient, exposes Send/SendPrompt commands, and simulates typing by inserting a temporary "..." assistant message and replacing it with the final response.
• MainPage.xaml: CollectionView with EmptyView containing four sample prompts as big bordered buttons.

Run (Windows desktop)

Build and run the Windows target. Once running, pick a sample prompt or type your own and press Send.

Useful docs and resources

• Microsoft.Extensions.AI overview — learn.microsoft.com/dotnet/ai/microsoft-extensions-ai
• Azure AI Foundry integration with IChatClient (Aspire) — learn.microsoft.com/dotnet/aspire/azureai/azureai-foundry-integration#client-integration
• Azure OpenAI / Azure AI Foundry quickstart (environment setup) — learn.microsoft.com/azure/ai-foundry/openai/chatgpt-quickstart#set-up
• NuGet packages:
  • Microsoft.Extensions.AI
  • Microsoft.Extensions.AI.OpenAI
  • Azure.AI.OpenAI
  • CommunityToolkit.Mvvm

Notes

• This sample prefers environment variables for desktop development and ignores mobile configuration.
• If you change models or endpoints, restart the app after updating environment variables.