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Editorial Team
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Asked: 2026-06-05T17:22:43+00:00

I need to return an a generic list in the correct order for my

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I need to return an a generic list in the correct order for my project, and I’m getting InvalidCastException errors. Here is the code:

Dim lDt As List(Of Comment) = RemapCommentsForE1(so.CommentList). _
OrderBy(Function(x) x.CreateDate.Value). _
ThenBy(Function(x) x.Sequence). _
ThenBy(Function(x) x.SubSequence)

Note that:

  • CreateDate is a Nullable(Of DateTimeOffset)
  • Sequence is a Nullable(Of Int32)
  • SubSequence is a Nullable(Of Int32)

The exact error I’m getting is:

Unable to cast object of type
‘System.Linq.OrderedEnumerable2[DTDataUploader.Comment,System.Int32]'
to type 'System.Collections.Generic.List1[DTDataUploader.Comment]’.

I’ve tried converting to the actual types…

Dim lDt As List(Of Comment) = RemapCommentsForE1(so.CommentList). _
OrderBy(Function(x) x.CreateDate.Value). _
ThenBy(Function(x) Convert.ToInt32(x.Sequence)). _
ThenBy(Function(x) Convert.ToInt32(x.SubSequence))

… but I get the same error. What am I missing here?

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1 Answer

  1. Editorial Team

    LINQ operations like Where and OrderBy produce queries, not results. As the error states, the result of your full LINQ expression is an OrderedEnumerable(Of DTDataUploader.Comment, System.Int32), not a list.

    To turn this into a list, add a call to ToList() to the end of the expression.

    Dim lDt As List(Of Comment) = RemapCommentsForE1(so.CommentList). _
OrderBy(Function(x) x.CreateDate.Value). _
ThenBy(Function(x) x.Sequence). _
ThenBy(Function(x) x.SubSequence).ToList()
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