Grid - UrlAdaptor / DataManagerRequest / operation.PerformFiltering error : 'Object reference not set to an instance of an object.'

Question

I get the following error : System.NullReferenceException : 'Object reference not set to an instance of an object.'
when doing an operation.PerformFiltering in a DataManagerRequest on my Grid UrlAdaptor

Here is my ContactController :

        [HttpPost]
        public IActionResult UrlDatasource([FromBody] DataManagerRequest dm)
        {

            IEnumerable<Contact> contacts = _context.Contact.Include(c => c.CreateBy).Include(c => c.Customer).AsEnumerable();
            DataOperations operation = new DataOperations();

            if (dm.Search != null && dm.Search.Count > 0)
            {
                contacts = operation.PerformSearching(contacts, dm.Search); //Search
            }
            if (dm.Sorted != null && dm.Sorted.Count > 0) //Sorting
            {
                if (!dm.Sorted.Any(item => item.Name.Contains(".")))
                {
                    contacts = operation.PerformSorting(contacts, dm.Sorted);
                }
            }
            if (dm.Where != null && dm.Where.Count > 0)
            {
                //dm.Where[0].IgnoreCase = false;
                contacts = operation.PerformFiltering(contacts, dm.Where, dm.Where[0].Operator);     //Filtering
            }

            if (dm.Skip != 0)
            {
                contacts = operation.PerformSkip(contacts, dm.Skip);   //Paging
            }
            if (dm.Take != 0)
            {
                contacts = operation.PerformTake(contacts, dm.Take);
            }
            return Ok(new { result = contacts, count = contacts.Count() });

        }

The where condition seems OK to me (I tried with IgnoreCase = false also but doesn't seem to be a PascalCase problem...

What should be done to get this filter working ?

Best regards,

Romain

Manivel Sellamuthu · Accepted Answer

Hi Romain,

Thanks for your update.

We checked the attached sample and we found that you have implemented URL service in the WebAPI controller. By default the URL adaptor is not compatible with WebAPI controller. So, we suggest you to use webApi adaptor for the Grid to resolve the reported issue.

For WebApiAdaptor we need to handle the Grid actions such as filtering, paging, sorting in server side by manually. By default grid sends request to the server for all the grid actions like Paging, Sorting, Filtering, Searching etc., in the controller side you can perform these operation with the correspond queries and return the data with Items & Count value pair which will be bound to the grid.

Please refer the below documentation and code example for more information.

Documentation: https://ej2.syncfusion.com/documentation/grid/data-binding/#web-api

OrderController.cs

public class OrderController : Controller

{

// GET: api/Orders

[HttpGet]

public object Get()

{

var queryString = Request.Query;

// perform the operation using the concern querystring

int skip = Convert.ToInt32(queryString["$skip"]); //paging

int take = Convert.ToInt32(queryString["$top"]);

string filter = queryString["$filter"]; // filtering

string sort = queryString["$orderby"]; // sorting

var data = OrdersDetails.GetAllRecords();

List<OrdersDetails> Datae = new List<OrdersDetails>();

List<OrdersDetails> Datase = new List<OrdersDetails>();

if (sort != null) //Sorting

{

switch (sort)

{

// here you can perform sorting action

case "OrderID":

if (sort.Substring(sort.IndexOf(' ') + 1) != null)

data = data.OrderByDescending(x => x.OrderID).ToList();

else

data = data.OrderBy(x => x.OrderID).ToList();

break;

case "CustomerID":

if (sort.Substring(sort.IndexOf(' ') + 1) != null)

data = data.OrderByDescending(x => x.CustomerID).ToList();

else

data = data.OrderBy(x => x.CustomerID).ToList();

break;

case "ShipCity":

if (sort.Substring(sort.IndexOf(' ') + 1) != null)

data = data.OrderByDescending(x => x.ShipCity).ToList();

else

data = data.OrderBy(x => x.ShipCity).ToList();

break;

case "ShipCountry":

if (sort.Substring(sort.IndexOf(' ') + 1) != null)

data = data.OrderByDescending(x => x.ShipCountry).ToList();

else

data = data.OrderBy(x => x.ShipCountry).ToList();

break;

}

if (filter != null)

{

// here you can perform filtering action

var newfiltersplits = filter;

var filtersplits = newfiltersplits.Split('(', ')', ' ');

var filterfield = filtersplits[1];

var filtervalue = filtersplits[3];

if (filtersplits.Length != 5)

{

filterfield = filter.Split('(', ')', '\'')[3];

filtervalue = filter.Split('(', ')', '\'')[5];

}

switch (filterfield)

{

case "OrderID":

Datae = (from cust in data

where cust.OrderID.ToString() == filtervalue.ToString()

select cust).ToList();

break;

case "EmployeeID":

Datae = (from cust in data

where cust.EmployeeID.ToString() == filtervalue.ToString()

select cust).ToList();

break;

case "Freight":

Datae = (from cust in data

where cust.Freight.ToString() == filtervalue.ToString()

select cust).ToList();

break;

case "CustomerID":

Datae = (from cust in data

where cust.CustomerID.ToLower().StartsWith(filtervalue.ToString())

select cust).ToList();

break;

case "ShipCity":

Datae = (from cust in data

where cust.ShipCity.ToLower().StartsWith(filtervalue.ToString())

select cust).ToList();

break;

case "ShipCountry":

Datae = (from cust in data

where cust.ShipCountry.ToLower().StartsWith(filtervalue.ToString())

select cust).ToList();

break;

}

Datase.AddRange(Datae);

// count = Datase.Count;

data = Datase;

}

// return the data with Items and Count pair

return new

{

Items = data.Skip(skip).Take(take),

Count = data.Count()

// return order;

};

}

// GET: api/Orders/5

[HttpGet("{id}", Name = "Get")]

public string Get(int id)

{

return "value";

}

// POST: api/Orders

[HttpPost]

public object Post([FromBody]OrdersDetails value)

{

OrdersDetails.GetAllRecords().Insert(0, value);

return value;

}

// PUT: api/Orders/5

[HttpPut]

public object Put(int id, [FromBody]OrdersDetails value)

{

var ord = value;

OrdersDetails val = OrdersDetails.GetAllRecords().Where(or => or.OrderID == ord.OrderID).FirstOrDefault();

val.OrderID = ord.OrderID;

val.EmployeeID = ord.EmployeeID;

val.CustomerID = ord.CustomerID;

val.Freight = ord.Freight;

val.OrderDate = ord.OrderDate;

val.ShipCity = ord.ShipCity;

return value;

}

// DELETE: api/ApiWithActions/5

[HttpDelete("{id:int}")]

[Route("Orders/{id:int}")]

public object Delete(int id)

{

OrdersDetails.GetAllRecords().Remove(OrdersDetails.GetAllRecords().Where(or => or.OrderID == id).FirstOrDefault());

return Json(id);

}

public class Data

{

public bool requiresCounts { get; set; }

public int skip { get; set; }

public int take { get; set; }

}

<ejs-grid id="Grid">

<e-data-manager url="/api/Orders" adaptor="WebApiAdaptor" crossdomain="true"></e-data-manager>

<e-grid-columns>

<e-grid-column field="OrderID" headerText="Order ID" type="number" textAlign="Right" width="120"></e-grid-column>

<e-grid-column field="CustomerID" headerText="Customer ID" type="string" width="140"></e-grid-column>

<e-grid-column field="Freight" headerText="Freight" textAlign="Right" format="C2" width="120"></e-grid-column>

<e-grid-column field="OrderDate" headerText="Order Date" format='yMd' textAlign="Right" width="140"></e-grid-column>

</e-grid-columns>

</ejs-grid>

Please let us know, if you need further assistance.

Regards,

Manivel

Please let us know, if you need further assistance. Regards, Manivel

Manivel Sellamuthu · Answer

Hi Romain, Greetings from Syncfusion support. We have checked the reported issue at our end with menu filter, but we are not facing the reported issue. Please refer the tried code example and screenshot for more information.

public IActionResult UrlDatasource([FromBody]DataManagerRequest dm) { IEnumerable DataSource = order; DataOperations operation = new DataOperations(); if (dm.Search != null && dm.Search.Count > 0) { DataSource = operation.PerformSearching(DataSource, dm.Search); //Search } if (dm.Sorted != null && dm.Sorted.Count > 0) //Sorting { DataSource = operation.PerformSorting(DataSource, dm.Sorted); } if (dm.Where != null && dm.Where.Count > 0) //Filtering { DataSource = operation.PerformFiltering(DataSource, dm.Where, dm.Where[0].Operator); } int count = DataSource.Cast().Count(); if (dm.Skip != 0) { DataSource = operation.PerformSkip(DataSource, dm.Skip); //Paging } if (dm.Take != 0) { DataSource = operation.PerformTake(DataSource, dm.Take); } return dm.RequiresCounts ? Json(new { result = DataSource, count = count }) : Json(DataSource); } \ Could you please share the below details, which will be helpful for us to validate further about issue. Share the complete Grid code Share the Syncfusion packages version Regards, Manivel

Romain Fabbri · Answer

Please run attached solution (run both WebApi & WebManager)

Update-Database

Register a user & login

https://localhost:44386/Customer/Contact

You shall get the reported error.

Attachment: _AlienErp_syncf_ticket_f2e1b9fe.zip

Jason Smith · Answer

I have personally googled this issue extensively, (using this grid in a .NET 7 project) and i can say as from Feb 2023, the URLadapter works perfectly fine, the issue is the Nullreference occurs because the column names are serialised as camelCase, so you class might have a property called "EmployeeName", but the DataManagerRequest and associated DataOperations object is trying to filter on "employeeName", which is how you get the nullreference,

if you change your ActionResult method to return something like this then filtering works fine:

return Json(new { result = DataSource, count = TotalRecords }, new System.Text.Json.JsonSerializerOptions() { PropertyNamingPolicy = null });

Pavithra Subramaniyam · Answer

Hi Jason Smith,Thanks for updating with the solution you have tried. Please
get back to us for further assistance.Regards,Pavithra S

Virang Patel · Answer

Could oyu explain further where to do this at? when you return at the end, doesn't the filtering exception happen before you return the result anyways?

Pavithra Subramaniyam · Answer

Hi Virang Patel,You can resolve the casing problem serializing and returning them
in the PascelCase format using the below code in the startup.cs file of
the application,If the ASP.NET CORE version is 2.X then add the below code in startup.cs
file

public void ConfigureServices(IServiceCollection services)
  {
      services.AddMvc().AddJsonOptions(options
  =>
      {
         
  options.SerializerSettings.ContractResolver = new
  Newtonsoft.Json.Serialization.DefaultContractResolver();
      });
  }

If the ASP.NET CORE version is 3.X and more, then add the
below code in startup.cs file

public void
  ConfigureServices(IServiceCollection services)
           
  {
                       
  services.AddMvc().AddNewtonsoftJson(options =>
           
  {
                  
  options.SerializerSettings.ContractResolver =
                     
  new DefaultContractResolver();
            });

}

To use AddNewtonsoftJson in
your project we need include the Microsoft.AspNetCore.Mvc.NewtonsoftJson
assemblyNote : We need to install NewtonSoft.JSON as
dependency since Syncfusion.EJ2.AspNet.Core dependent to
NewtonSoft.JSON package.Refer to the below documentation for
more information.UG: https://ej2.syncfusion.com/aspnetcore/documentation/grid/data-binding/data-binding#troubleshoot-grid-render-rows-without-dataRegards,Pavithra S

Ahmed · Answer

Good day folks, I had the same issue and tried for hours to fix it even with what

Jason Smith comment I wasn't able to fixed.Finally I noticed that the filter works when at list one sort is done. Otherwise the filter doesn't work. So I added this peace of code to my javascript file :  $(document).ready(function () {    document.getElementById("myGrid").ej2_instances[0].sortSettings.properties.columns.push({ field: 'myDefaultSortingColumn', direction: 'Descending' });  })Now, filtering is working properly when page is loaded.

Aishwarya Rameshbabu · Answer

Hi
Ahmed,We
understand that you have resolved your issue on your own. Please get back to us if you
have further queries or if you are still facing the reported issue.RegardsAishwarya
R