Group distinct records in column

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Hi Everyone,

Can you help on how to to do this using linq in vb.net?
The Datatable1 columns should be group same like Datatable2 result.

Datatable1

ID# | NAME | DEPT
E12345 | Joe | HR
E12345 | Joe | HR
E12345 | Joe | HR
T54333 | Fred | IT
T54333 | Fred | IT
I22544 | Kate | AC
I22544 | Kate | AC

Expected result
Datatable2
ID# | NAME | DEPT
E12345 | Joe | HR
T54333 | Fred | IT
I22544 | Kate | AC

What I have tried:

Tried below code but the column NAME, DEPT has system error result.

Dim dt As DataTable = New DataTable()
        dt.Columns.AddRange(New DataColumn() _
            {
                New DataColumn("ID#", Type.GetType("System.String")),
                New DataColumn("Name", Type.GetType("System.String")),
                New DataColumn("Dept", Type.GetType("System.String"))
            })

        dt.Rows.Add(New Object() {"E12345", "Joe", "HR"})
        dt.Rows.Add(New Object() {"E12345", "Joe", "HR"})
        dt.Rows.Add(New Object() {"E12345", "Joe", "HR"})
        dt.Rows.Add(New Object() {"T54333", "Fred", "IT"})
        dt.Rows.Add(New Object() {"T54333", "Fred", "IT"})
        dt.Rows.Add(New Object() {"I22544", "Kate", "AC"})
        dt.Rows.Add(New Object() {"I22544", "Kate", "AC"})

        Dim groupID = dt.AsEnumerable() _
        .GroupBy(Function(x) x.Field(Of String)("ID#")) _
        .Select(Function(grp) New With
               {
                    .ID = grp.Key,
                    .Name = grp.Select(Function(x) x.Field(Of String)("Name")),
                    .Dept = grp.Select(Function(x) x.Field(Of String)("Dept"))
               }) _
            .ToList()

        Dim dtF As DataTable = dt.Clone()

        For Each item In groupID
            Dim dr = dtF.NewRow()
            'dr("ID#") = item.ID
            'dr("Name") = item.Name
            dtF.Rows.Add(item.ID, item.Name, item.Dept)
        Next

        DataGridView1.DataSource = dtF

Posted 24-Oct-19 20:19pm

icavs

Updated 24-Oct-19 21:03pm

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2 solutions

Solution 2

var distinctObj = customer.Select(m => new {m.Id, m.Name,m.Dept}).Distinct().ToList();

Posted 24-Oct-19 21:03pm

Member 8653884

Comments

Maciej Los 25-Oct-19 3:34am

Well...
This question has been tagged as: VB.net, BUT(!) you showed an example in c#.

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Maciej Los · Accepted Answer · 2019-10-24T20:59:00

You need to add FirstOrDefault() method to get single Name and Dept instead of list of them.

VB

Dim groupID = dt.AsEnumerable() _
.GroupBy(Function(x) x.Field(Of String)("ID#")) _
.Select(Function(grp) New With
       {
            .ID = grp.Key,
            .Name = grp.Select(Function(x) x.Field(Of String)("Name")).FirstOrDefault(),
            .Dept = grp.Select(Function(x) x.Field(Of String)("Dept")).FirstOrDefault()
       }) _
    .ToList()