Default return type in DOTNETCORE webapi
In ASP.NET Core Web API, the default return type for an action method is an `ActionResult<T>` where `T` is the type of data you want to return. `ActionResult<T>` is a flexible and powerful way to return data from your API because it allows you to return different HTTP status codes and handle various scenarios.
Here's how you can use `ActionResult<T>` in a typical ASP.NET Core Web API action method:
```csharp
[ApiController]
[Route("api/[controller]")]
public class ValuesController : ControllerBase
{
[HttpGet("{id}")]
public ActionResult<string> Get(int id)
{
// Simulated logic to get data based on the provided ID
if (id > 0)
{
// Return 200 OK status code with a string value
return Ok($"Value for ID {id}");
}
else
{
// Return 400 Bad Request status code with an error message
return BadRequest("Invalid ID");
}
}
}
In this example, the `Get` action method returns an `ActionResult<string>`. Inside the method, you can use the `Ok()` method to return a 200 OK status code along with the string value. Similarly, you can use other methods like `BadRequest()`, `NotFound()`, `CreatedAtAction()`, etc., to return different HTTP status codes.
If you don't specify a return type explicitly, ASP.NET Core Web API allows you to return the following types directly from action methods:
- **`Task<IActionResult>`:** For asynchronous action methods that return different types of `ActionResult` based on logic.
- **`ActionResult`:** When you need to return a specific HTTP status code without a response body.
- **`ObjectResult`:** When you need to return a specific HTTP status code along with an object (e.g., a custom DTO).
- **`ActionResult<T>`:** When you want to return a specific HTTP status code along with a strongly typed object (`T`).
You can choose the appropriate return type based on your API's requirements and the desired behavior for different scenarios.
