ASP.NET MVC Telerkik AutoComplete Not displaying record

Question

I want Telerik MVC UI AutoComplete work with my EducationEntities, but returns null. Don't know why? Here is my code:

@(Html.Kendo().AutoComplete()
      .Name("students")
      .DataTextField("DisplayName")
      .Placeholder("Enter student name")
      .DataSource(source =>
      {
        source.Read(read =>
        {
            read.Action("GetStudents", "StudentDetails").Data("onAdditionalData"); ;
        }).ServerFiltering(true);
      })          
      .HtmlAttributes(new { style = "width:240px" })
      .Filter(FilterType.Contains)
      .MinLength(1)
      .Suggest(true)
      .Height(340)
      .HeaderTemplate("<div class=\"dropdown-header\">" +
                    "<span class=\"k-widget k-header\">Photo</span>" +
                    "<span class=\"k-widget k-header\">Contact info</span>" +
                "</div>")
      .Template("<span><img src='/Content/Images/${data}.jpg' " +
                        "width='20' height='20' />&nbsp;${data}</span>")
      .Template("<span class=\"k-state-default\"><h3>#: data.DisplayName #</h3></span>")
      .Template("<span class=\"k-state-default\"><img src=\"" + Url.Content("~/Content/Images/") + "#:data.StudentID#.jpg\" alt=\"#:data.StudentID#\" /></span>" +
                "<span class=\"k-state-default\"><h3>#: data.DisplayName #</h3><p>#: data.Address #</p></span>")
)

here is my action that should return full student details.

public JsonResult GetStudents(string name)
    {
        var students = new EducationEntities().Student.Select(student => new Student
        {
            StudentID = student.StudentID,
            DisplayName = student.DisplayName,
            FirstName = student.FirstName,
            LastName = student.LastName                
        });

        if (!string.IsNullOrEmpty(name))
        {
            students = students.Where(p => p.DisplayName.Contains(name));
        }

        return Json(students, JsonRequestBehavior.AllowGet);
    }

function onAdditionalData() { return { name: $("#students").val() }; } — Badar Ali, Jan 26 '15 at 07:47
Did you check to see if the right value is being sent to the controller? Set a break point and inspect the data coming in the `name` parameter. Tell me if it's what you expected to be. — Andrei V, Jan 26 '15 at 07:53
I have debugged it again, action GetStudents() takes name but doesn't return value once found. — Badar Ali, Jan 26 '15 at 08:07
You have, in my opinion, several problems there. You are taking all the `Student` records from the database and filter it in you action. This is not really efficient. Also, the `students` object does not contain any values because the sql query is not called. — Andrei V, Jan 26 '15 at 08:10

Andrei V · Accepted Answer · 2015-01-26T08:37:37.113

You should change your action to this:

Create a student model

 public class StudentModel
 {
      public int StudentID { get; set; }
      public string DisplayName { get; set; }
      public string FirstName { get; set; }
      public string LastName { get; set; }
 }

and change the action accordingly

public JsonResult GetStudents(string name)
{
     //initialize the result
     var students = new List<StudentModel>();

     //check for filter value; if any, than filter
     if (!string.IsNullOrEmpty(name))
     {
         students = new EducationEntities().Student
                    .Where(student => student.DisplayName.Contains(name))
                    .Select(student => new StudentModel
                    {
                        StudentID = student.StudentID,
                        DisplayName = student.DisplayName,
                        FirstName = student.FirstName,
                        LastName = student.LastName                
                    }).ToList();
     }
     else
     {
         //depending on your requirements, you could return all the students when there's no filter set
         students = new EducationEntities().Student.Select(student => new StudentModel
                    {
                        StudentID = student.StudentID,
                        DisplayName = student.DisplayName,
                        FirstName = student.FirstName,
                        LastName = student.LastName                
                    }).ToList();
     }

     return Json(students, JsonRequestBehavior.AllowGet);
}

Please note that you need to explicitly call ToList() for the query to be executed and populate your variable with the result.

It generated this error: The entity or complex type 'EducationModel.Student' cannot be constructed in a LINQ to Entities query. — Badar Ali, Jan 26 '15 at 08:31
@BadarAli, your `Student` object is bound to the database. You cannot "create" them. You need to create an additional model and store the selected students using it. See my edited answer. Please read [this post](http://stackoverflow.com/questions/5325797/the-entity-cannot-be-constructed-in-a-linq-to-entities-query) for additional information. — Andrei V, Jan 26 '15 at 08:40

ASP.NET MVC Telerkik AutoComplete Not displaying record

1 Answers1