Compare Json subitem date with current datetime in c#view

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 Map1Async()
{
string empty = "Unknown";
var items = await DocumentDBRepository.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;
@if (a.Length > 50) { a = a.Substring(0, 50); }
@if (item.GroupId != 82)
{
if (myday <= DateTime.Now.AddDays(-7))
{
@myday
"/Content/Images/trafficlight-red2.png" width="20" height="20">"@Url.Action("DevicePage", "Device", new { item.DeviceId })">
@a..
}
else
{"/Content/Images/trafficlight-green1.png" width="20" height="20">"@Url.Action("DevicePage", "Device", new { item.DeviceId })">
@a..
}
}
else
{
if (myday <= DateTime.Now.AddDays(-7))
{
"/Content/Images/trafficlight-red2.png" width="20" height="20">"@Url.Action("Form", "TARP", new { item.DeviceId })">
@a..
}
else
{"/Content/Images/trafficlight-green1.png" width="20" height="20">"@Url.Action("Form", "TARP", new { item.DeviceId })">
@a..
}
}
@if (item.IPaddress != "0")
{
Site Id: @newsiteId;
}
@if (item.LastPing != null)
{
Last Contact: @Html.DisplayFor(modelItem => item.LastContact.Ping), @Html.DisplayFor(modelItem => item.BatVoltage)V
}

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Laxmidhar Sahoo6y ago
hi
Your model class is not properly assign in the view page.In the view page where call the model calss can show the code . like
@model DeviceMap

and whar is the cs file path in your project
Laxmidhar Sahoo6y ago
hi

In the view page call the model . That is on the top of the view page Like

@model folder.subfolder.DeviceMap

If your app and model in the same folder then

@model DeviceMap

for reference

https://docs.microsoft.com/en-us/aspnet/mvc/overview/getting-started/introduction/accessing-your-models-data-from-a-controller

Then change to

Last Contact: @Html.DisplayFor(model => model.LastContact.Ping)

others are also changed
Ana H6y ago
Got Error by doing so:

Error CS1061

'IEnumerable' does not contain a definition for 'LastContact' and no accessible extension method 'LastContact' accepting a first argument of type 'IEnumerable' could be found (are you missing a using directive or an assembly reference?)

@Laxmidher sahoo
Laxmidhar Sahoo6y ago
hi
Html.DisplayFor(modelItem => item.LastContact.Ping);"
Here you use lambda Expresion the object reference is modelItem so you have to call by modelItem like
Html.DisplayFor(modelItem => modelItem.LastContact.Ping);"

Compare Json subitem date with current datetime in c#view

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