DataTable.Select.Where VB.Net - Delete rows

Question

I'm currently pulling information using a query that I'm not allowed to tamper with:

Dim dt As DataTable = BLL.GetData(variable).Tables(0)

Immediately afterwards, I'm removing any records where a field begins with a specific value:

For Each dr As DataRow In dt.Rows
    If dr.Item(2).ToString().StartsWith("value") Then
        dr.Delete()
    End If
Next

What I'd really like to do is something like:

dt.Select.Where(field1 => field1.StartsWith("value")).Delete()

I know that is not the syntax of it and I'm probably very off from what it would be like. The For Each works fine, I'm just trying to "simplify" it. Any idea? Any and all help is appreciated.

Justin Niessner · Accepted Answer · 2012-12-20 19:00:04Z

3

Actually, your initial code is probably the cleanest and most straight forward.

To delete items using LINQ, you first need to read them into a separate collection, then loop through that collection and call Delete on each record. If you'd rather go that route, you could try:

Dim records = dt.Rows.Where(Function(r) r.StartsWith("value")).ToList()
For Each r In records
    r.Delete()
Next

answered Dec 20, 2012 at 19:00

Justin Niessner

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2 Comments

Justin Niessner Over a year ago

@user574632 - If you simply wanted a collection with the rows that don't start with "value", then yes. But the OP specifically says they want to delete the rows.

XstreamINsanity Over a year ago

Hmmm, both ways might work. This is pre-draw to the screen, so either doing the NOT or deleting them might work.

Christopher K · Accepted Answer · 2017-07-03 20:43:18Z

The answer I think you are looking for is below from Microsoft. https://msdn.microsoft.com/en-us/library/det4aw50(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-2

Dim table As DataTable = DataSet1.Tables("Orders")

' Presuming the DataTable has a column named Date.
Dim expression As String
expression = "Date > #1/1/00#"
Dim foundRows() As DataRow

' Use the Select method to find all rows matching the filter.
foundRows = table.Select(expression)

Dim i As Integer
' Print column 0 of each returned row.
For i = 0 to foundRows.GetUpperBound(0)
   Console.WriteLine(foundRows(i)(0))
Next i

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