LinkGenerator returns NULL Url 而 Url.Action 没有...为什么

LinkGenerator returns NULL Url while Url.Action doesn't ... Why

在 ASP.NET Core 2.2 控制器上,我尝试以 3 种方式生成 Link:

var a = Url.Action(action: "GetContentByFileId", values: new { fileId = 1 });

var b = _linkGenerator.GetUriByAction(HttpContext, action: "GetContentByFileId", controller: "FileController", values: new { fileId = 1 });

var c = _linkGenerator.GetUriByAction(_httpContextAccessor.HttpContext, action: "GetContentByFileId", controller: "FileController", values: new { fileId = 1 });

结果

我正在控制器中注入 Link生成器,它不为空 ...

我也在注入 HttpContextAccessor 并且启动时有:

services.AddSingleton<IActionContextAccessor, ActionContextAccessor>();

services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();

文件控制器是:

[ApiVersion("1.0", Deprecated = false), Route("v{apiVersion}")]
public class FileController : Controller {

  private readonly IHttpContextAccessor _httpContextAccessor;
  private readonly LinkGenerator _linkGenerator; 

  public FileController(IHttpContextAccessor httpContextAccessor, LinkGenerator linkGenerator) {

    _httpContextAccessor = httpContextAccessor;
    _linkGenerator = linkGenerator;

  }

  [HttpGet("files/{fileId:int:min(1)}")]
  public async Task<IActionResult> GetContentByFileId(FileGetModel.Request request) {
    // Remaining code
  }

我错过了什么?

更新

除了 TanvirArjel 回答的 Controller 后缀之外,我能够指出问题所在。

如果我注释以下代码行,所有网址都是正确的:

[ApiVersion("1.0", Deprecated = false), Route("v{apiVersion}")]

但是如果我在启动时添加前面的代码行和以下代码:

services.AddApiVersioning(x => {
  x.ApiVersionSelector = new CurrentImplementationApiVersionSelector(x);
  x.AssumeDefaultVersionWhenUnspecified = true;
  x.DefaultApiVersion = new ApiVersion(1, 0);
  x.ReportApiVersions = false;
});

然后 url 变为 null ...

这个 ApiVersion 添加的是 "v1.0" 在文件之前所以它变成了 "v1.0/files".

所以link生成器应该变成:

var b = _linkGenerator.GetUriByAction(HttpContext, 
  action: "GetContentByFileId", 
  controller: "File", 
  values: new { apiVersion = "1.0", fileId = 1 
});

问题

有没有办法在不指定的情况下将 apiVersion 集成到 LinkGenerator 中?

问题是您使用的控制器名称带有 Controller 后缀。请去掉控制器名称的Controller后缀,写成如下:

var b = _linkGenerator.GetUriByAction(HttpContext, 
    action: "GetContentByFileId", 
    controller: "File", 
    values: new { FileId = 1 }
);

现在应该可以了。

         app.UseEndpoints(endpoints =>
          {
            // Default route
            endpoints.MapControllerRoute(
                name: "default",
                pattern: "{controller=Account}/{action=Login}/{id?}");
           });

services.AddMvc(options => options.EnableEndpointRouting = true);

      string url = _generator.GetUriByAction("index", "home", null, 
 _accessor.HttpContext.Request.Scheme, _accessor.HttpContext.Request.Host);
        var url1 = _generator.GetPathByAction("index", "home", 
   new { FileId = 1 });