下面是一个工作示例，如下所示:

1.Controller:

  [Route("api/[controller]")]公共类ValuesController:控制器{[HttpGet]公共DateTime Get(){var data = DateTime.Now;返回数据；}//POST api/< controller>[HttpPost]公共DateTime Post([FromBody]字符串值){var data = DateTime.Parse(value);返回数据；}} 

2.Startup.cs:

  public void ConfigureServices(IServiceCollection服务){services.AddControllers().AddNewtonsoftJson(options =>{var dateConverter = new Newtonsoft.Json.Converters.IsoDateTimeConverter{DateTimeFormat ="dd'-'MM'-'yyyy'T'HH':'mm"};options.SerializerSettings.Converters.Add(dateConverter);options.SerializerSettings.Culture = new CultureInfo("en-IE");options.SerializerSettings.DateFormatHandling = DateFormatHandling.IsoDateFormat;});services.AddSwaggerGen(c =>{c.SwaggerDoc("v1"，新的OpenApiInfo {标题=我的API"，版本="v1"})；});}//此方法由运行时调用.使用此方法来配置HTTP请求管道.公共无效配置(IApplicationBuilder应用程序，IWebHostEnvironment env){如果(env.IsDevelopment()){app.UseDeveloperExceptionPage();}app.UseSwagger();app.UseSwaggerUI(c =>{c.SwaggerEndpoint("/swagger/v1/swagger.json"，我的API V1");});app.UseHttpsRedirection();app.UseRouting();app.UseAuthorization();app.UseEndpoints(endpoints =>{endpoints.MapControllers();});} 

结果:

如果您在项目中使用本地化，请像

I am wondering if anyone can help me, I am trying to change the date format in swagger UI from

2020-03-07T14:49:48.549Z

to

07-03-2020T14:49

I am trying to remove the seconds and put the date format into "dd/MM/yyyy HH:mm", now I have tried

    services.AddControllers()
        .AddNewtonsoftJson(options =>
        {
            var dateConverter = new Newtonsoft.Json.Converters.IsoDateTimeConverter
            {
                DateTimeFormat = "dd'/'MM'/'yyyy HH:mm:ss"
            };

            options.SerializerSettings.Converters.Add(dateConverter);
            options.SerializerSettings.Culture = new CultureInfo("en-IE");
            options.SerializerSettings.DateFormatHandling = DateFormatHandling.IsoDateFormat;
        })

I seen various example on the web and none of which seems to work.

Here is a working demo like below:

1.Controller:

[Route("api/[controller]")]
public class ValuesController : Controller
{
    [HttpGet]
    public DateTime Get()
    {
        var data = DateTime.Now;
        return data;
    }

    // POST api/<controller>
    [HttpPost]
    public DateTime Post([FromBody]string value)
    {
        var data = DateTime.Parse(value);
        return data;
    }
}

2.Startup.cs:

public void ConfigureServices(IServiceCollection services)
{           
    services.AddControllers()
    .AddNewtonsoftJson(options =>
    {
        var dateConverter = new Newtonsoft.Json.Converters.IsoDateTimeConverter
        {
            DateTimeFormat = "dd'-'MM'-'yyyy'T'HH':'mm"
        };

        options.SerializerSettings.Converters.Add(dateConverter);
        options.SerializerSettings.Culture = new CultureInfo("en-IE");
        options.SerializerSettings.DateFormatHandling = DateFormatHandling.IsoDateFormat;
    });
    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "My API", Version = "v1" });
    });
}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    app.UseSwagger();

    app.UseSwaggerUI(c =>
    {
        c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
    });      

    app.UseHttpsRedirection();

    app.UseRouting();

    app.UseAuthorization();
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();                
    });

}

Result:

If you use localization in your project,please configure like this and then change like below:

1.Startup.cs:

public void ConfigureServices(IServiceCollection services)
{
    services.AddLocalization(options => options.ResourcesPath = "Resources");

    services.AddControllers().AddViewLocalization(
    LanguageViewLocationExpanderFormat.Suffix,
    opts => { opts.ResourcesPath = "Resources"; })
    .AddDataAnnotationsLocalization()
    .AddNewtonsoftJson(options =>
    {
        var dateConverter = new Newtonsoft.Json.Converters.IsoDateTimeConverter
        {
            DateTimeFormat = "dd'-'MM'-'yyyy'T'HH':'mm"
        };

        options.SerializerSettings.Converters.Add(dateConverter);
        options.SerializerSettings.Culture = new CultureInfo("en-IE");
        options.SerializerSettings.DateFormatHandling = DateFormatHandling.IsoDateFormat;
    }); 

    services.Configure<RequestLocalizationOptions>(options =>
    {
        var supportedCultures = new CultureInfo[] {
            new CultureInfo("en"),
            new CultureInfo("de"),
            new CultureInfo("en-IE")
    };
        options.DefaultRequestCulture = new RequestCulture("en");
        options.SupportedCultures = supportedCultures;
        options.SupportedUICultures = supportedCultures;

        options.RequestCultureProviders = new[]{ new CustomRouteDataRequestCultureProvider{
            IndexOfCulture=1,
        }};
    });

    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "My API", Version = "v1" });
    });
}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    app.UseSwagger();

    app.UseSwaggerUI(c =>
    {
        c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
    });
    var options = app.ApplicationServices.GetService<IOptions<RequestLocalizationOptions>>();
    app.UseRequestLocalization(options.Value);

    app.UseHttpsRedirection();


    app.UseRouting();

    app.UseAuthorization();
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
        endpoints.MapControllerRoute("LocalizedDefault", "{culture:cultrue}/{controller=Home}/{action=Index}/{id?}");

    });

}

2.Controller:

[Route("{culture?}/api/[controller]")]
//[Route("api/[controller]")]
public class ValuesController : Controller
{}

Result: