Question

I have two tables. One table is called Occurrence that contains the following:

OccurrenceID | EmployeeID | OccurrenceDate | Points | Comment
-------------------------------------------------------------
1            |1           |2012-01-01      |5       |yada    
2            |1           |2012-02-01      |3       |blah    
3            |2           |2012-03-01      |2       |yada

The other table is called Employee and contains the following:

EmployeeID | EmployeeName
-------------------------
 1         |Jack
 2         |Jill

I am trying to group these two tables together and end up with a single line for each employee that will show the total points in a view in my MVC 4 project. So for the above example my output should be:

Name    | Points
----------------
Jack    |8
Jill    |2

Here is the LINQ query that I’ve tried in my Controller:

        var groupedOccurrences = from o in db.Occurrences.Include(o => o.Employee)
                                 where o.OccurrenceDate >= beginDate
                                    && o.OccurrenceDate <= endDate
                                 group o by new {o.EmployeeID, o.Points} into g
                                 select new {
                                     Name = g.Key.EmployeeID,
                                     Total = g.Sum(o => o.Points)
                                 };

        return View(groupedOccurrences);

And here is my View:

@model IEnumerable<PtoTracker.Occurrence>

<table>
    <tr>
        <th>
            Employee
        </th>
        <th>
            Total Pts.
        </th>
    </tr>

@foreach (var item in Model) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.Employee.EmployeeName)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Points)
        </td>
    </tr>
}
</table>

When I navigate to this view I get this error:

The model item passed into the dictionary is of type ‘System.Data.Entity.Infrastructure.DbQuery1[<>f__AnonymousType32[System.Int32,System.Int32]]’, but this dictionary requires a model item of type ‘System.Collections.Generic.IEnumerable`1[PtoTracker.Occurrence]’.

Can someone help me understand what I should be doing differently?

Answer 1

You need to new up instances of your view expected class

var groupedOccurrences = 
   (from o in db.Occurrences.Include(o => o.Employee)
    where o.OccurrenceDate >= beginDate && o.OccurrenceDate <= endDate
    group o by new {o.EmployeeID, o.Points} into g
    select new { Name = g.Key.EmployeeID, Total = g.Sum(o => o.Points)}
   ).AsEnumerable();


var model = groupedOccurrences.Select(item => new PtoTracker.Occurrence { 
                         Name = item.Name,
                         Total = item.Total });

your view is expecting IEnumerable of PtoTracker.Occurrence but you are sending it an IQuerable of anonymes type instead.