CODEWITHSUNDEEP
vb.netlinqlinq-to-entities
Sam Axe
Sam Axe

Reputation: 33738

How to resolve issue: "At least one object must implement IComparable."

So here's the line that is erring:

@For Each item In futureClasses.OrderBy(
        Function(c) c.ClassDates.OrderBy(
            Function(d) d.Value).ToList).ToList

The relevant parts of the class structure are:

Public Class [Class]
  Public Property ClassDates As List(Of ClassDate) = New List(Of ClassDate)
End Class

Public Class ClassDate
  Implements IComparable(Of ClassDate)

  Public Property Value As Date

Public Function CompareTo(other As ClassDate) As Integer Implements IComparable(Of ClassDate).CompareTo
  Return Me.Value < other.Value
End Function  

End Class

The idea is to construct a list of [Class] objects (to iterate over) that are in order by which one occurs first in the stream of time.

The error I get is:

At least one object must implement IComparable.

I've set a breakpoint on that line. When the error occurs futureClasses contains 2 [Class] elements, each with a single ClassDate.

The values are:
futureClasses(0).ClassDates(0).Value = #3/13/2014#
futureClasses(1).ClassDates(0).Value = #4/17/2014#

Does anyone see why this wee or is being thrown?

Upvotes: 0

Views: 1492

Answers (1)

Jason Roell
Jason Roell

Reputation: 6809

I think what you are looking for is something like this:

futureClasses.OrderBy(Function(c) c.ClassDates.OrderBy(Function(d) d.Value).First().Value).ToList

Upvotes: 2

Related Questions