Question

I need to convert linq query result to list. I tried the following code:

var qry = from a in obj.tbCourses
                     select a;

List<course> lst = new List<course>();
lst = qry.ToList();

The following error occurred for the above code:

Cannot implicitly convert type 
System.Collections.Generic.List<Datalogiclayer.tbcourse> to
System.Collections.Generic.List<course>
Was it helpful?

Solution

No need to do so much works..

var query = from c in obj.tbCourses
        where ...
        select c;

Then you can use:

List<course> list_course= query.ToList<course>();

It works fine for me.

OTHER TIPS

List<course> = (from c in obj.tbCourses
                 select 
                new course(c)).toList();

You can convert the entity object to a list directly on the call. There are methods to converting it to different data struct (list, array, dictionary, lookup, or string)

You need to somehow convert each tbcourse object to an instance of course. For instance course could have a constructor that takes a tbcourse. You could then write the query like this:

var qry = from c in obj.tbCourses
          select new course(c);

List<course> lst = qry.ToList();

You need to use the select new LINQ keyword to explicitly convert your tbcourseentity into the custom type course. Example of select new:

var q = from o in db.Orders
        where o.Products.ProductName.StartsWith("Asset") && 
              o.PaymentApproved == true
        select new { name   = o.Contacts.FirstName + " " +
                              o.Contacts.LastName, 
                     product = o.Products.ProductName, 
                     version = o.Products.Version + 
                              (o.Products.SubVersion * 0.1)
                   };

http://www.hookedonlinq.com/LINQtoSQL5MinuteOverview.ashx

What you can do is select everything into a new instance of Course, and afterwards convert them to a List.

var qry = from a in obj.tbCourses
                     select new Course() {
                         Course.Property = a.Property
                         ...
                     };

qry.toList<Course>();
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