How to update column value using LINQ Query

Question

I am learning LINQ Query, and I want to update one column value using LINQ Query, can someone please guide me, Below is what I have.

Dim dtMytable As New Strongly_TypedTable
dtMytable.Merge(Contact.LoadContact(User, lstIds))
For Each r In dtMytable 
       r.id = ' Some Args.Value
Next

But I want to use LINQ to achieve it.

Something like

dtMytable .Where(Function(c) ' what to write here` ).ToList()

Linq is for querying... Not intended for updating, theres other approaches. — Trevor, Aug 23 '17 at 05:05

score 2 · Answer 1 · answered Apr 20 '20 at 04:24

If your update is for few columns following approach can be used.

 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
 Dim dt As New DataTable("tblEntTable")
 dt.Columns.Add("ID", GetType(String))
 dt.Columns.Add("Amount", GetType(Decimal))
 dt.Rows.Add(New Object() {"1", 100.51})
 dt.Rows.Add(New Object() {"2", 200.52})
 dt.Rows.Add(New Object() {"3", 500.24})
 dt.Rows.Add(New Object() {"4", 400.31})
 dt.Rows.Add(New Object() {"5", 600.88})
 dt.Rows.Add(New Object() {"6", 700.11})

 MethodSyntax(dt)
 'QuerySyntax(dt)
End Sub

Sub MethodSyntax(ByVal dt As DataTable)
 Array.ForEach(dt.AsEnumerable().ToArray(), Sub(row) row("Amount") = 900.23)
 DataGridView1.DataSource = dt
End Sub

Sub QuerySyntax(ByVal dt As DataTable)
 Dim result = From row In dt.AsEnumerable()
     Select New With { _
     .ID = row.Field(Of String)("ID"), _
     .Amount = 800
     }

 DataGridView1.DataSource = result.ToList()
End Sub

score 1 · Answer 2 · answered May 25 '23 at 11:00

1

dtMytable.Select("Amount > 100").ToList().ForEach(Sub(row)
                                              row("Amount") = 250
                                             End Sub)

answered May 25 '23 at 11:00

senthilkumar2185

2,536
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Ayaz · Answer 3 · 2017-08-22T17:56:57.877

0

Use Foreach linq extention

dtMytable.AsEnumerable().ForEach(Sub(obj) obj.Field<int>("id") = New value)

edited Aug 22 '17 at 17:56

answered Aug 22 '17 at 17:17

Ayaz

2,111
4
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Use the column you want to update. From the question, I can see that you want to update "id". – Ayaz Aug 22 '17 at 17:51
I get error as foreach is not a member of your dtMytable – Unbreakable Aug 22 '17 at 17:53
Updated the answer. Can u try that? Make sure, You have "Import System.Linq" namespace included. – Ayaz Aug 22 '17 at 17:57
*Import -> Imports – Unbreakable Aug 22 '17 at 18:04

How to update column value using LINQ Query

3 Answers3

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