Question

我在使用[FromQuery]属性进行模型绑定时遇到问题。

我有以下课程：

public class PaginationSettings
{
    public const int DefaultRecordsPerPage = 5;

    public PaginationSettings(int pageIndex, int recordsPerPage)
    {
        RecordsPerPage = recordsPerPage == 0 ? DefaultRecordsPerPage : recordsPerPage;
        PageIndex = pageIndex == 0 ? 1 : pageIndex;
    }

    public int RecordsPerPage { get; set; }
    public int PageIndex { get; set; }
    public int RecordsStartIndex => RecordsPerPage * (PageIndex - 1);

    public static PaginationSettings Normalize(PaginationSettings source)
    {
        if (source == null)
        {
            return new PaginationSettings(0, 0);
        }

        return new PaginationSettings(source.PageIndex, source.RecordsPerPage);
    }
}

查询：

public class GetBlogListQuery : IRequest<IExecutionResult>
{
    public string Filter { get; set; }
    public PaginationSettings PaginationSettings { get; set; }
}

最后是Controller方法：

[HttpGet]
[ProducesResponseType(200)]
[ProducesResponseType(204)]
public async Task<IActionResult> GetBlogs([FromQuery] GetBlogListQuery query)
{
   ...
}

如果尝试使用以下URL调用Get，则会获得HTTP 500。

http://localhost:5000/api/Blogs/GetBlogs?PaginationSettings.RecordsPerPage=2&PaginationSettings.PageIndex=2

Answer 1

从docs

为了使绑定发生，该类必须具有公共默认值构造函数和要绑定的成员必须是公共可写属性。当模型绑定发生时，该类将仅使用实例化公共默认构造函数，则可以设置属性

因此，为了使模型绑定起作用。向PaginationSettings类添加一个公共默认构造函数（默认构造函数是可以不带参数调用的构造函数）

public class PaginationSettings
{
    public PaginationSettings(){ }
    ...the other stuff
}

Asp.Net Core [FromQuery]绑定

1 个答案: