Group By Query

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  1. TWill
    TWill avatar
    1 posts
    Member since:
    Sep 2013

    Posted 11 Sep 2013 Link to this post

    I have the following group by LINQ query in C# that I'm trying to rewrite in VB, but I get an error on my vb code. Can anyone see what is wrong with it.
    var dupValues = from mrows in dtLoadedData.Select()
    group mrows by new
    a = mrows.Field<object>(compositeColls[0].ColumnName),
    b = mrows.Field<object>(compositeColls[1].ColumnName),
    c = mrows.Field<object>(compositeColls[2].ColumnName),
    d = mrows.Field<object>(compositeColls[3].ColumnName)
    into grp where grp.Count() >= 2 select new { grp.Key.a, grp.Key.b, grp.Key.c, grp.Key.d, e = grp.Count() };
    Dim dupValues = From grp In From mrows In dtLoadedData.[Select]() Group mrows By New With { _
    a = mrows.Field(Of Object)(compositeColls(0).ColumnName), _
    b = mrows.Field(Of Object)(compositeColls(1).ColumnName), _
    c = mrows.Field(Of Object)(compositeColls(2).ColumnName), _
    d = mrows.Field(Of Object)(compositeColls(3).ColumnName) _
    } Into grp() Where grp.Count() >= 2 Select New With { _
    grp.Key.a, grp.Key.b, grp.Key.c, grp.Key.d, Key .e = grp.Count() }

    Error: Anonymous type member name must be preceded by a period
  2. Greg
    Greg avatar
    44 posts
    Member since:
    Jun 2012

    Posted 30 Oct 2013 Link to this post

    As the error message states anonymous type initialization syntax in VB requires a period before the property name. E.g.
    New With _
     .a = mrows.Field...
     .b = ...
  3. Doroteya
    Doroteya avatar
    498 posts

    Posted 04 Nov 2013 Link to this post

    Hello TWill and Greg,

    Indeed, as Greg points, declaring an anonymous type in VB requires a period before the names of the properties. This article can provide you with details about the subject.

    Additionally, I would suggest to you to try rewriting the query that causes the error like this:
    Dim dupValues = From mrows In dtLoadedData.Select()
               Group mrows By GroupKey = New With
                   .a = mrows.Field(Of Object)(compositeColls(0).ColumnName),
                   .b = mrows.Field(Of Object)(compositeColls(1).ColumnName),
                   .c = mrows.Field(Of Object)(compositeColls(2).ColumnName),
                   .d = mrows.Field(Of Object)(compositeColls(3).ColumnName)
               } Into grp = Group
               Where grp.Count() >= 2
               Select New With
                   .e = grp.Count()

    I hope you find this feasible. If you have additional questions, or experience difficulties with the suggested solution, do not hesitate to get back to us.

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