Access Cosmos Db JSON data using C# MVC

Question

I am trying to display Cosmos db JSON Subitems using c# MVC Web application. But I am getting an error:

Could not cast or convert from System.DateTime to WebApplication1.Models.Entry.

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>}

I want to disply Ping date and time. Please, help. Also if you have resources on how to call different styled JSON data please provide link for reference. Thank you.

In the JSON, LastContact is a single Entry object. But in your model LastContact is of type Dictionary<string, Entry>. What should it be? — devNull
– devNull, Commented Jan 9, 2020 at 3:08
LastContact is single entry object. but not sure how to call it — Ana
– Ana, Commented Jan 9, 2020 at 3:17
change the objects in your Entry class to DateTime and change Dictionary<string, Entry> to just Entry. — Jawad
– Jawad, Commented Jan 9, 2020 at 3:18
Can you please explain more or provide informative link @Jawad — Ana
– Ana, Commented Jan 9, 2020 at 3:41

Jawad · Accepted Answer · 2020-01-09 04:40:37Z

1

public class DeviceMap
{
    [JsonProperty(PropertyName = "id")]
    public string Id { get; set; } // Suggestion: Change this to 'Guid' instead of string

    [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; }
}

Your LastContact will deserialize correctly if you select DateTime as the type of each variable in Entry.

Testing

I used your json and converted it to DeviceMap object to test it and make sure that above works.

{
  "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
}

and used the following in my main to deserialize it to make sure it works correctly.

DeviceMap map = JsonConvert.DeserializeObject<DeviceMap>(json);

It is definitely better to define the types in class so that at time of deserialization, you wont have to parse it to the types they should be. Deserializer should take care of that for you and convert your strings to type of your class if it is convertible, like, automatically converting string to Guid or DateTime.

edited Jan 9, 2020 at 4:40

answered Jan 9, 2020 at 3:52

Jawad

11.4k3 gold badges28 silver badges43 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

Ana Over a year ago

after adding Deserialization code, I am getting error "CS0103 C# The name 'json' does not exist in the current context" I have aalso added Newtonsoft.Json library. @Jawad

Jawad Over a year ago

json is a string that holds the content of your json data. Thats my test variable.

Jawad Over a year ago

@Ana, were you able to sort this out?

Ana Over a year ago

No still struggling with it. @Jawad Can you please explain more

Jawad Over a year ago

@Ana Have you updated the classes like mentioned here? How are you deserializing the json

|

Collectives™ on Stack Overflow

Access Cosmos Db JSON data using C# MVC

1 Answer 1

9 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

9 Comments

Your Answer

Sign up or log in

Post as a guest

Related