Linq .FirstOrDefault() returning a single object error

Question

User-250171173 posted

Hello, hoping someone can let me know why I'm having trouble returning a single object...  thx

Here is the linq code 

    public static IEnumerable<SingleStatusReport> GetStatusReport(int id)
    {                
        var status = (
            from w in db.Status
            where w.ProjectRef == id
            orderby w.CreatedDate descending
            select new SingleStatusReport { ID = w.ID, Description = w.Description, CreatedDate = w.CreatedDate }).FirstOrDefault();

        return status;
    }

Here is the data model

public class SingleStatusReport
    {
        public int ID { get; set; }
        public Nullable<System.DateTime> CreatedDate { get; set; }
        public string Description { get; set; }
    }

Here is the error

CS0029: Cannot implicitly convert type 'AnonymousType#1' to 'System.Collections.Generic.List<ProjectData.Models.SingleStatusReport>'

Answer 1

User467960235 posted

Refer this link.

http://stackoverflow.com/questions/17836799/cannot-implicitly-convert-type-listanonymoustype1-to-listwebapplication

It may help you

Answer 2

User-250171173 posted

replacing FirstOrDefault() with ToList() the code works fine, however it returns multiple of records.

I want to return just the most recent record hence the .FirstOrDefault().  It is the use of .FirstOrDefault() that is causing the error, and I don't understand why, or how I may fix it.  

Answer 3

User37182867 posted

The problem is not in your Linq statement, its in your Function Signature.

Try changing it to

public static SingleStatusReport GetStatusReport(int id)

which should hand your error of

CS0029: Cannot implicitly convert type 'AnonymousType#1' to 'System.Collections.Generic.List<ProjectData.Models.SingleStatusReport>'

However you will need to updated your variable type to be type specific as well... so make this change too

var status = (
change to
SingleStatusReport status = (

 

Answer 4

User-775946742 posted

You  are return different type of value in program

 public static IEnumerable<SingleStatusReport> GetStatusReport(int id)
    {                
        var status = (
            from w in db.Status
            where w.ProjectRef == id
            orderby w.CreatedDate descending
            select new SingleStatusReport { ID = w.ID, Description = w.Description, CreatedDate = w.CreatedDate }).FirstOrDefault();

        return status;
    }

you can change this

 public static IEnumerable<SingleStatusReport>  GetStatusReport(int id) 
{ 
     var status = ( from w in db.Status where w.ProjectRef == id orderby w.CreatedDate descending select 
       new SingleStatusReport { ID = w.ID, Description = w.Description, CreatedDate = w.CreatedDate })
       .tolist();
 return status;
 }

Answer 5

User-271186128 posted

Hi 2bitcoder,

public static IEnumerable<SingleStatusReport> GetStatusReport(int id)
    {                
        var status = (
            from w in db.Status
            where w.ProjectRef == id
            orderby w.CreatedDate descending
            select new SingleStatusReport { ID = w.ID, Description = w.Description, CreatedDate = w.CreatedDate }).FirstOrDefault();

        return status;
    }

The above method will return an IEnumerable<SingleStatusReport> value. If you are using the FistOrDefault() method in this method, it just return a SingleStatusReport.

So, I suggest you could try to modify your code as below:

   public static SingleStatusReport GetStatusReport(int id)
    {                
        var status = (
            from w in db.Status
            where w.ProjectRef == id
            orderby w.CreatedDate descending
            select new SingleStatusReport { ID = w.ID, Description = w.Description, CreatedDate = w.CreatedDate }).FirstOrDefault();

        return status;
    }

Or, you could also try to use the following code:

    public static IEnumerable<SingleStatusReport> GetStatusReport(int id)
    {                
        var status = (
            from w in db.Status
            where w.ProjectRef == id
            orderby w.CreatedDate descending
            select new SingleStatusReport { ID = w.ID, Description = w.Description, CreatedDate = w.CreatedDate }).ToList();

        return status;
    }

Then, use the following code to get the first SingleStatusReport.

   var query2 = GetStatusReport(id).FirstOrDefault();

Best Regard,
Dillion