[HttpPost]
  public async Task<JsonResult> SaveNewCustomerAsnyc(AddCustomerInput input)
  {
   if (!ModelState.IsValid)
   {
    return Json(Result.FromCode(ResultCode.InvalidParams));
   }

   .....
  }

public class ApiValidationFilter : IActionFilter
 {
  public bool AllowMultiple => false;

  public async Task<HttpResponseMessage> ExecuteActionFilterAsync(HttpActionContext actionContext, CancellationToken cancellationToken, Func<Task<HttpResponseMessage>> continuation)
  {
   var method = actionContext.ActionDescriptor.GetMethodInfoOrNull();
   if (method == null)
   {
    return await continuation();
   }   

   if (!actionContext.ModelState.IsValid)
   {
    var error = actionContext.ModelState.GetValidationSummary();
    var result = Result.FromError($"參數(shù)驗證不通過：{error}", ResultCode.InvalidParams);
    return actionContext.Request.CreateResponse(result);
   }

   return await continuation();
  }
}

public static class ModelStateExtensions
 {
  /// <summary>
  /// 獲取驗證消息提示并格式化提示
  /// </summary>
  public static string GetValidationSummary(this ModelStateDictionary modelState, string separator = "\r\n")
  {
   if (modelState.IsValid) return null;

   var error = new StringBuilder();

   foreach (var item in modelState)
   {
    var state = item.Value;
    var message = state.Errors.FirstOrDefault(p => !string.IsNullOrWhiteSpace(p.ErrorMessage))?.ErrorMessage;
    if (string.IsNullOrWhiteSpace(message))
    {
     message = state.Errors.FirstOrDefault(o => o.Exception != null)?.Exception.Message;
    }
    if (string.IsNullOrWhiteSpace(message)) continue;

    if (error.Length > 0)
    {
     error.Append(separator);
    }

    error.Append(message);
   }

   return error.ToString();
  }
 }

if (!ModelState.IsValid)
{
  return BadRequest(ModelState);
}

public class ApiBehaviorOptions
  {
    public Func<ActionContext, IActionResult> InvalidModelStateResponseFactory { get; set; }

    public bool SuppressModelStateInvalidFilter { get; set; }

    public bool SuppressInferBindingSourcesForParameters { get; set; }

    public bool SuppressConsumesConstraintForFormFileParameters { get; set; }
  }

public void ConfigureServices(IServiceCollection services)
    {      
      services
         .AddMvc()
        .AddXmlSerializerFormatters() //設(shè)置支持XML格式輸入輸出
        .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

      //禁用默認行為
      services.Configure<ApiBehaviorOptions>(options =>
      {
        options.SuppressModelStateInvalidFilter = true;
      });
    }

public void ConfigureServices(IServiceCollection services)
    {
      .....
      services
         .AddMvc(options =>
         {
           options.Filters.Add<ApiValidationFilter>();
         })
        .AddXmlSerializerFormatters() //設(shè)置支持XML格式輸入輸出
        .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

    }

public void ConfigureServices(IServiceCollection services)
    {      
      services
         .AddMvc()
        .AddXmlSerializerFormatters() //設(shè)置支持XML格式輸入輸出
        .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

      //參數(shù)驗證
      services.Configure<ApiBehaviorOptions>(options =>
      {
        options.InvalidModelStateResponseFactory = (context) =>
        {
          var error = context.ModelState.GetValidationSummary();
          
          return new JsonResult(Result.FromError($"參數(shù)驗證不通過：{error.ToString()}", ResultCode.InvalidParams));
        };
      });
    }