The [FromQuery] attribute tells an ASP.NET Core minimal API to bind a handler parameter from query-string data. It can also name the query key explicitly. section 7.2 section 7.4
Use [FromQuery] when you need to make query binding explicit or separate a parameter name from its query key:
- Override convention-based binding for simple values such as int and string. section 7.2
- Bind repeated query values to an array, such as ?id=123&id=456. section 7.4
- Use Name to keep a descriptive handler parameter while matching the client’s query key. section 7.4
- Remember that an explicit source takes precedence, and a failed required binding returns 400 Bad Request without trying another source. section 7.8
Rename the handler parameter without changing the URL
app.MapGet("/products/search", ([FromQuery(Name = "id")] int[] ids) => $"Received {ids.Length} ids"); A request to /products/search?id=123&id=456 binds both values to ids, while the handler keeps a clear plural name. section 7.4
Listing 7.1 Binding simple values using [From] attributes
using Microsoft.AspNetCore.Mvc; #1
WebApplicationBuilder builder = WebApplication.CreateBuilder(args);
WebApplication app = builder.Build();
app.MapGet("/products/{id}/paged",
([FromRoute] int id, #2
[FromQuery] int page, #3
[FromHeader(Name = "PageSize")] int pageSize) #4
=> $"Received id {id}, page {page}, pageSize {pageSize}");
app.Run();
Compare explicit binding for route, query-string, and header values in one minimal API endpoint. section 7.2
