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VB.Net Generic List Get Unique Values By A Single Property

Hi..
I have a Generic LIst I need to populate another Generic List with Only the Unique Objects bases Only on a single Property called Name.

I'm using .Net 2.0 - I can't use LINQ !   (Which would be easy...)

Any ideas of the best way... thanks

     
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JElster
Asked:
JElster
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2 Solutions
 
x77Commented:
I think you need distinct "Name" from Objects in MyList.
For that, use a dictionary:

Dim D as new Dictionary (of String,MyObjectType)(MyList.Count)
For each e in MyList
   if D.Contains(e.Name) = False then D.Add(Name, e)
Next
Dim NewList as List(of String)(D.Keys) '        Dim NewList as List(of MyObjectType)(D.Values)
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lenordisteCommented:
actually there is an easier way with the list but I don't know the VB syntax. I ll fire up VS2008 and let you know in a minute.
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lenordisteCommented:
ok I finally found out the syntax (I hate VB...):

The idea is to use Linq's Distinct() method and provide it with a method to compare your objects (see code below).

Another solution could be to do a group and then select one element (the first or last or whatever):
Dim distinctList = fullList.GroupBy(Function(n) n.Name).Select(Function(o) o.First())

Public Class NameCompare
        Implements System.Collections.Generic.IEqualityComparer(Of MyObject)

        Public Function Equals1(ByVal x As MyObject, ByVal y As MyObject) As Boolean Implements   System.Collections.Generic.IEqualityComparer(Of MyObject).Equals
            Return IIf(x.Name = y.Name, True, False)
        End Function

        Public Function GetHashCode1(ByVal x As MyObject) As Integer Implements System.Collections.Generic.IEqualityComparer(Of MyObject).GetHashCode
            Return x.Name.ToString.ToLower.GetHashCode()
        End Function
    End Class

Dim fullList As List(Of MyObject)
Dim distinctList = fullList.Distinct(New NameCompare())

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lenordisteCommented:
mmmmm never mind that ... I just realised in your question that you can't use Linq (I read the contrary).
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