What causes my date to come in this format: /Date(1640035318903)/ in C# from the controller?

Question

My records are coming back from the server in C# in this format:

(via network tab / preview on the network call)

DateModified: "/Date(1640035318903)/"

What would cause this issue? Why won't it just come back like this?

This is how I'm returning it via my controller via a post:

        /// <summary>
        /// Gets the application file manager file system items.
        /// </summary>
        /// <param name="fileManagerJsParam">The file manager js parameter.</param>
        /// <returns>
        /// ActionResult
        /// </returns>
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<ActionResult> GetFileManagerFileSystemItems(FileManagerJsParamModel fileManagerJsParam)
        {
            if (fileManagerJsParam == null)
            {
                throw new ArgumentNullException(nameof(fileManagerJsParam));
            }

            if (!ModelState.IsValid)
            {
                return Json(new
                {
                    success = false,
                    errorMessage = string.Join(
                    ",",
                    ModelState.Values.Where(e => e.Errors.Count > 0)
                    .SelectMany(e => e.Errors)
                    .Select(e => e.ErrorMessage)
                    .ToArray())
                });
            }

            var csModel = mapper.Map<FileManagerCsParamModel>(fileManagerJsParam);

            var result = await fileManagerUtilities.GetApplicationFileManagerFileSystemItems(csModel, 107);

            return Json(result.FileSystemItems);
        }

Here is my javascript that calls it:

function getItemsFileManager(e) {
    var deferred = $.Deferred()

    let fullUrl = baseEndPoint + loadAction;

    // check to see if we have different base end point / load action urls
    if (e && e.dataItem) {
        var fileManagerAPIItems = getFileManagerAPIItems(e.dataItem);

        if (fileManagerAPIItems) {
            fullUrl = fileManagerAPIItems.BaseEndPoint + fileManagerAPIItems.LoadAction;
        }
    }

    let fileManagerJsParam = getFileManagerParams(e, true);

    if (!fileManagerJsParam) {
        console.log("fileManagerParms not set in getItemsFileManager @ " + new Date());
        genericErrorMessage();
        return;
    }

    $.post(BuildSafeURL(fullUrl, null), fileManagerJsParam)
    .done(function (data) {
        deferred.resolve(data);
    })
    .fail(function (error) {
        deferred.reject(getItemGenericErrorMessage(e));

        if (error && error.responseJSON && error.responseJSON.errorMessage) {
            console.log("error⚠️", error.responseJSON.errorMessage);
        }
        else {
            console.log("error⚠️", error);
        }
    });

    return deferred.promise();
}

Answer 1

I found the result from this post: https://stackoverflow.com/a/9302054 (Approach 2).

I had to update all my controller http post calls to return Task<JsonResult> / return new CustomJsonResult { Data = result.FileSystemItems };

Here is the code:

namespace WebPortal.MVC.Utilities
{
    using System;
    using System.Web;
    using System.Web.Mvc;
    using Newtonsoft.Json;
    using Newtonsoft.Json.Converters;

    /// <summary>
    /// CustomJsonResult
    /// </summary>
    /// <seealso cref="JsonResult" />
    public class CustomJsonResult : JsonResult
    {
        private const string DateFormat = "yyyy-MM-ddTHH:mm:ssZ";

        /// <summary>
        /// Executes the result.
        /// </summary>
        /// <param name="context">The context.</param>
        /// <exception cref="System.ArgumentNullException">context</exception>
        public override void ExecuteResult(ControllerContext context)
        {
            if (context == null)
            {
                throw new ArgumentNullException("context");
            }

            HttpResponseBase response = context.HttpContext.Response;

            if (!string.IsNullOrEmpty(ContentType))
            {
                response.ContentType = ContentType;
            }
            else
            {
                response.ContentType = "application/json";
            }

            if (ContentEncoding != null)
            {
                response.ContentEncoding = ContentEncoding;
            }

            if (Data != null)
            {
                // Using Json.NET serializer
                var isoConvert = new IsoDateTimeConverter();
                isoConvert.DateTimeFormat = DateFormat;
                response.Write(JsonConvert.SerializeObject(Data, isoConvert));
            }
        }
    }
}

        /// <summary>
        /// Gets the application file manager file system items.
        /// </summary>
        /// <param name="fileManagerJsParam">The file manager js parameter.</param>
        /// <returns>
        /// ActionResult
        /// </returns>
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<JsonResult> GetFileManagerFileSystemItems(FileManagerJsParamModel fileManagerJsParam)
        {
            if (fileManagerJsParam == null)
            {
                throw new ArgumentNullException(nameof(fileManagerJsParam));
            }

            if (!ModelState.IsValid)
            {
                return Json(new
                {
                    success = false,
                    errorMessage = string.Join(
                    ",",
                    ModelState.Values.Where(e => e.Errors.Count > 0)
                    .SelectMany(e => e.Errors)
                    .Select(e => e.ErrorMessage)
                    .ToArray())
                });
            }

            var csModel = mapper.Map<FileManagerCsParamModel>(fileManagerJsParam);

            var result = await fileManagerUtilities.GetApplicationFileManagerFileSystemItems(csModel, 107);

            return new CustomJsonResult { Data = result.FileSystemItems };
        }

Results: