c# - 在Web API中使用ExceptionFilterAttribute

我正在尝试在创建的web api中实现错误处理，需要以json格式返回异常详细信息。我创建了balexceptionfilterate属性

public class BALExceptionFilterAttribute : ExceptionFilterAttribute
{
    public override void OnException(HttpActionExecutedContext actionExecutedContext)
    {
        base.OnException(actionExecutedContext);
        actionExecutedContext.Response = actionExecutedContext.Request.CreateResponse(HttpStatusCode.BadRequest, new { error = actionExecutedContext.Exception.Message });
    }
}

并在gloal.asax.cs中注册

GlobalConfiguration.Configuration.Filters.Add(new BALExceptionFilterAttribute());

在我的控制器中，我想抛出异常

    [HttpGet]
    [BALExceptionFilter]
    public HttpResponseMessage Getdetails(string ROOM, DateTime DOB_GT)
    {
        if (string.IsNullOrEmpty(ROOM)
        {
            return Request.CreateResponse(new { error = "Input paramete cannot be Empty or NULL" });
        }
            //throws the exception
            throw new BALExceptionFilterAttribute();

            List<OracleParameter> prms = new List<OracleParameter>();
            List<string> selectionStrings = new List<string>();
            prms.Add(new OracleParameter("ROOM", OracleDbType.Varchar2, ROOM, ParameterDirection.Input));
            prms.Add(new OracleParameter("DOB_GT", OracleDbType.Date, DOB_GT, ParameterDirection.Input));
            string connStr = ConfigurationManager.ConnectionStrings["TGSDataBaseConnection"].ConnectionString;
            using (OracleConnection dbconn = new OracleConnection(connStr))
            {
                DataSet userDataset = new DataSet();
                var strQuery = "SELECT * from LIMS_SAMPLE_RESULTS_VW where ROOM = :ROOM and DOB > :DOB_GT ";
                var returnObject = new { data = new OracleDataTableJsonResponse(connStr, strQuery, prms.ToArray()) };
                var response = Request.CreateResponse(HttpStatusCode.OK, returnObject, MediaTypeHeaderValue.Parse("application/json"));
                ContentDispositionHeaderValue contentDisposition = null;
                if (ContentDispositionHeaderValue.TryParse("inline; filename=TGSData.json", out contentDisposition))
                {
                    response.Content.Headers.ContentDisposition = contentDisposition;
                }
                return response;
               }
        }

但它在throw new BALExceptionFilterAttribute();
Error 1 The type caught or thrown must be derived from System.Exception

最佳答案

//throws the exception
throw new BALExceptionFilterAttribute();

会产生编译器错误。异常筛选器属性是在发生异常时执行某些操作，以便您可以以一般方式处理它，如重定向到错误页或在json响应中发回一般异常消息等。异常筛选器属性本身不是异常，它处理异常。
因此throw new BALExceptionFilterAttribute();无效，因为BALExceptionFilterAttribute不是例外。
如果需要BALException类型，请创建一个。

public class BALException : Exception { /* add properties and constructors */}

现在你可以扔了

throw new BALException();

然后，您可以将BALExceptionFilterAttribute配置为在该异常到达筛选器（未在控制器中捕获）时执行某些操作。