如何为方法返回的IEnumerable设置MaxLengthAttribute(用于生成swagger maxItems

Question

我有一个返回数组的控制器方法：

[ApiController]
[Route("[controller]")]
[Produces("application/json")]
public class WeatherForecastController : ControllerBase
{
[HttpGet]
//[MaxLength(10)]   // <- !!!!!!!!!!!!!!
public  IEnumerable<WeatherForecast> Get([FromQuery] WeatherForecastQuery query)
...

已经为该控制器生成了一个swagger规范，该规范描述了一系列没有最小/最大项属性的响应

...
"responses": {
"200": {
"description": "Success",
"content": {
"application/json": {
"schema": {
"type": "array",
"items": {
"$ref": "#/components/schemas/WeatherForecast"
},
//minItems: 1,   // <- I want it
//maxItems: 10,  // <- I want it
}}}}}
...

如何将min/maxItems属性添加到方法返回数组中？

Answer 1

MaxLengthAttribute不是方法允许的属性，

它的目标是

[System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.Property, AllowMultiple=false)]

https://learn.microsoft.com/en-us/dotnet/api/system.componentmodel.dataannotations.maxlengthattribute?view=netcore-3.1

另请参阅：

https://github.com/domaindrivendev/Swashbuckle.AspNetCore/issues/1747

Answer 2

您必须将数据注释[MaxLength(10)]放到WeatherForecastQuery对象中。我认为这个对象包含IEnumerable？

更新

如果我现在理解正确，您最多需要返回10个条目。

你可以返回一个像这样的新对象

public class GetWeatherForecastResponse {
[MaxLength(10)]
public IEnumerable<WeatherForecast> Result { get; set; }
}

那么你的控制器应该像这个

[ApiController]
[Route("[controller]")]
[Produces("application/json")]
public class WeatherForecastController : ControllerBase
{
[HttpGet]
public GetWeatherForecastResponse Get([FromQuery] WeatherForecastQuery query)
...