1# C# (.NET) Entry Point (DO NOT MODIFY)
2 
3The base Azure Functions template includes a properly configured `Program.cs` that should NOT be modified or replaced by recipes.
4 
5> ⛔ **CRITICAL**: Do NOT replace or modify `Program.cs` from the base template.
6 
7## Base Template Program.cs
8 
9The official `functions-quickstart-dotnet-azd` template uses:
10 
11```csharp
12using Microsoft.Azure.Functions.Worker;
13using Microsoft.Extensions.DependencyInjection;
14using Microsoft.Extensions.Hosting;
15 
16var host = new HostBuilder()
17    .ConfigureFunctionsWebApplication()  // ASP.NET Core integration
18    .ConfigureServices(services =>
19    {
20        services.AddApplicationInsightsTelemetryWorkerService();
21        services.ConfigureFunctionsApplicationInsights();
22    })
23    .Build();
24 
25host.Run();
26```
27 
28## Why This Matters
29 
30| Feature | ConfigureFunctionsWebApplication | ConfigureFunctionsWorkerDefaults |
31|---------|----------------------------------|----------------------------------|
32| ASP.NET Core integration | ✅ Yes | ❌ No |
33| IActionResult return types | ✅ Yes | ❌ No |
34| [FromBody] model binding | ✅ Yes | ❌ No |
35| App Insights integration | ✅ Built-in | ❌ Manual setup |
36| Modern HTTP handling | ✅ Yes | ⚠️ Limited |
37 
38## What Recipes Should Provide
39 
40Recipes only need to add:
411. **Trigger function files** (`.cs` files with `[Function]` attributes)
422. **Package references** (`.csproj` additions for extensions)
433. **App settings** (connection strings, configuration)
44 
45All triggers use attribute-based binding — no Program.cs modifications needed:
46- `[HttpTrigger]`, `[TimerTrigger]`, `[CosmosDBTrigger]`
47- `[ServiceBusTrigger]`, `[EventHubTrigger]`, `[BlobTrigger]`
48- `[DurableClient]`, `[SqlTrigger]`
49 
50## Common Mistake
51 
52❌ **WRONG** — Recipe overwrites Program.cs with outdated version:
53```csharp
54var host = new HostBuilder()
55    .ConfigureFunctionsWorkerDefaults()  // OLD PATTERN
56    .Build();
57```
58 
59✅ **CORRECT** — Recipe leaves Program.cs untouched, only adds function files.
60