Compare Json subitem date with current datetime in c#view

Question

Hi.. I am using azure cosmosdb database. I am displaying webpage using Cosmosdb data and c# MVC web application. This time database json filr have DateTime as subitem in Json. I need to compare it with current datetime to flag signal on view page. Please find attached source code.

 

I am getting error:

 

Object reference not set to an instance of an object.

 

if I use "DateTime myday [email protected];"

 

I get error:

 

Cannot implicitly convert type 'System.Web.Mvc.MvcHtmlString' to 'System.DateTime' if I use " DateTime myday = Html.DisplayFor(modelItem => item.LastContact.Ping);"

 

Can anybody help please.

 

My code is as follows:

 

JSON:

"DataTypeId": 1,
"IPaddress": "192.168.2.177",
"id": "d1b81653-b7a5-4d79-85ea-79c01f43f747",
"PhoneNo": "0417518324",
"LastContact": {
"EnvLog": "2019-09-07T19:41:08",
"Ping": "2020-01-09T12:10:09",
"SpdLog": "2019-09-07T19:41:08"
},
"SpeedLog": true,
"DeviceModelId": 2,
"DisconnectEvents": 9,

Model:

    public class DeviceMap
    {

        [JsonProperty(PropertyName = "id")]
        public string Id { get; set; }

        [JsonProperty(PropertyName = "IPaddress")]
        public string IPaddress { get; set; }

        [JsonProperty(PropertyName = "SpeedLog")]
        public bool SpeedLog { get; set; }

        [JsonProperty(PropertyName = "LastContact")]
        public Entry LastContact { get; set; }
    }

     public class Entry
    {

        [JsonProperty(PropertyName = "EnvLog")]
        public DateTime EnvLogtime { get; set; }

        [JsonProperty(PropertyName = "Ping")]
        public DateTime Ping { get; set; }

        [JsonProperty(PropertyName = "SpdLog")]
        public DateTime SpdLog { get; set; }
    }
    }

Controller:

    public class DeviceMapController : Controller
    {
        [ActionName("Index")]
        public async Task<ActionResult> Map1Async()
        {
            string empty = "Unknown";
            var items = await DocumentDBRepository<DeviceMap>.GetMap1Async(d => d.Id != null, d => d.Lat != empty);
            if (Convert.ToInt32(User.GroupId()) != 200)
                {
                    items = items.Where(d => d.GroupId == Convert.ToInt32(User.GroupId()));
            }
            return View(items);
        }
    }

View:

@foreach (var item in Model)
{
if ((@item.IPaddress == "192.168.2.14") || (@item.IPaddress == "192.168.2.13") || (@item.IPaddress == "192.168.2.15") || (@item.IPaddress == "192.168.2.16")) { }
else
{
//SideId string
string siteId = null;
string newsiteId = null;
if (item.IPaddress != "0")
{
int index = item.IPaddress.IndexOf('.') + 1;
int space = item.IPaddress.IndexOf('.', index + 1);
int space2 = item.IPaddress.IndexOf('.', space + 1);
int end = item.IPaddress.Length;
if (index > 0) { siteId = item.IPaddress.Substring(space + 1, end - space - 1); newsiteId = siteId.Replace('.', '-'); }
}
// string Cutoff =Html.DisplayFor(modelItem => item.LastContact.Ping).ToString();
// DateTime day = DateTime.Parse(Cutoff.Value,"dd/MM/yyyy HH:mm:ss", CultureInfo.CurrentCulture);
DateTime myday =Html.DisplayFor(modelItem => item.LastContact.Ping);
DateTime now = DateTime.Now;
DateTime yesterday = now.AddDays(-7);
DateTime d;
// DateTime.TryParseExact(myday,@"dd/MM/yyyy HH:mm:ss", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal,out d);

// if (Html.DisplayFor(modelItem => item.LastContact.Ping) != null) { d = DateTime.Parse(myday, "dd/MM/yyyy HH:mm:ss", CultureInfo.CurrentCulture); } else { myday = DateTime.ParseExact("08/04/2000 14:00:02", "dd/MM/yyyy HH: mm:ss", CultureInfo.CurrentCulture); }
string a = @item.Name;
<tr>
<td>
@if (a.Length > 50) { a = a.Substring(0, 50); }
@if (item.GroupId != 82)
{
if (myday <= DateTime.Now.AddDays(-7))
{<h4>@myday</h4>
<img src="/Content/Images/trafficlight-red2.png" width="20" height="20"><a href="@Url.Action("DevicePage", "Device", new { item.DeviceId })"><h6>@a..</h6></a>
}
else
{<img src="/Content/Images/trafficlight-green1.png" width="20" height="20"><a href="@Url.Action("DevicePage", "Device", new { item.DeviceId })"><h6>@a..</h6></a>
}
}
else
{
if (myday <= DateTime.Now.AddDays(-7))
{
<img src="/Content/Images/trafficlight-red2.png" width="20" height="20"><a href="@Url.Action("Form", "TARP", new { item.DeviceId })"><h6>@a..</h6></a>
}
else
{<img src="/Content/Images/trafficlight-green1.png" width="20" height="20"><a href="@Url.Action("Form", "TARP", new { item.DeviceId })"><h6>@a..</h6></a>
}
}
@if (item.IPaddress != "0")
{<p>Site Id: @newsiteId;</p>}
@if (item.LastPing != null)
{
<p>
Last Contact: @Html.DisplayFor(modelItem => item.LastContact.Ping), @Html.DisplayFor(modelItem => item.BatVoltage)V
</p>}