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创建ActionFilter以排除WebAPI中的空值

asp.net-mvc asp.net c#

-1

Chenna · 技术社区 · 7 年前

Suppress NULL Values in every API call

只想为一个方法抑制空值吗

1 回复 | 直到 7 年前

er-sho 7 年前

如果你使用 Formatters.JsonFormatter 在你的 WebApiConfig.cs 然后

1) 如果必须在应用程序级别忽略空值,则意味着所有api操作都将忽略空值

public class IgnoreNullValuesFilter : ActionFilterAttribute
{
    public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
    {
        actionExecutedContext.ActionContext.RequestContext.Configuration.Formatters.JsonFormatter.SerializerSettings = new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore };
        base.OnActionExecuted(actionExecutedContext);
    }
}

并将此筛选器添加到喜欢

config.Filters.Add(new IgnoreNullValuesFilter());

将此筛选器添加到后,您将发现所有api操作都返回忽略空值的数据

[IgnoreNullValuesFilter] 因为我们在 WebApiConfig.cs网站

WebApiConfig.cs网站

2) 如果必须使用操作筛选器忽略特定api操作的空值

public class IgnoreNullValuesFilter : ActionFilterAttribute
{
    public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
    {
        var objectContent = actionExecutedContext.Response.Content as ObjectContent;
        if (objectContent != null)
        {
            var type = objectContent.ObjectType;
            var value = JsonConvert.SerializeObject(objectContent.Value, Newtonsoft.Json.Formatting.Indented, new JsonSerializerSettings
            {
                NullValueHandling = NullValueHandling.Ignore
            });

            objectContent.Value = value;

            //If you want to send your response as strongly type
            JObject jObject = JObject.Parse(value);
            objectContent.Value = jObject;
        }

        base.OnActionExecuted(actionExecutedContext);
    }
}

以及忽略空值的api

[HttpGet]
[IgnoreNullValuesFilter]
public IHttpActionResult ApiName()
{
    var myObject = new Item { Id = 1, Name = "Matthew", Salary = 25000, Department = null };

    return Ok(myObject);
}

如果您想包含空值,那么只需从api中删除[IgnoreNullValuesFilter]

如果你不想使用任何动作过滤器

public class Item
{
    public int Id { get; set; }
    public string Name { get; set; }
    public long Salary { get; set; }
    public string Department { get; set; }
}

你的API看起来像

[HttpGet]
public IHttpActionResult ApiName()
{
    var myObject = new Item { Id = 1, Name = "Matthew", Salary = 25000, Department = null };

    return Json(myObject, new JsonSerializerSettings()
    {
        NullValueHandling = NullValueHandling.Ignore
    });
}

[HttpGet]
public IHttpActionResult ApiName()
{
    var myObject = new Item1 { Id = 1, Name = "Matthew", Salary = 25000, Department = null };

    var jsonIgnoreNullValues = JsonConvert.SerializeObject(myObject, Newtonsoft.Json.Formatting.Indented, new JsonSerializerSettings
        {
          NullValueHandling = NullValueHandling.Ignore
        });

    JObject jObject = JObject.Parse(jsonIgnoreNullValues);

    return Ok(jObject);
}

结果:

Item 有财产 department = null

你可以发送 myObject