DataGridView loses data I added to an added column!

Am I being dumb? I read a XML file into a DataGridView...

Code:

---

Dim oDSet = New System.Data.DataSet
oDSet.ReadXml(strFilePath)
DataGridView1.DataSource = oDSet.Tables(0)

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The XML file contents show in the grid OK.
I iterate through the rows, and if there's bad data in the row I set the colour to red, and add a value to what would end up as a hidden new column, with the intention of sorting later to show all the error rows together.

Code:

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        DataGridView1.Columns.Add("test1", "Errors")
        For Each drow As System.Windows.Forms.DataGridViewRow In DataGridView1.Rows
            If drow.Cells("Whatever").Value.ToString = "Wrong" Then
                DataGridView1.Rows(drow.Index).DefaultCellStyle.BackColor = Color.Red
                DataGridView1.Rows(drow.Index).Cells("test1").Value = "ERR"
            End If
        Next

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It sort of works, although I've found that I can't sort easily on a non-data-bound new column. :p

My question is, though, if I click on a column heading to sort, all my red changes - and new values in the new test1/"Errors" column - all vanish!
Why is that, and how do I actually achieve this? :)
Thanks

If you sort, you refresh the binding, so anything which hasn't been added to the underlying datatable will, well, disappear!

Thanks - so I have to manually copy the XML dataset to the DataGridView, so it's unbound - set up the columns by hand, etc - and all will be well....?
:)

Well, you could do that :eek: but I would add columns to the datatable and enter the 'hidden' values there so that the binding is always valid.

Aha, sounds like a plan :)
Thanks!

I'd be inclined to leave that column in there full time, even in the XML. It seems like it would be useful. Then, right after you set the datasource for the DGV, hide the column that you want hidden.

Thanks. Unfortunately the XML isn't mine, it's an export from some other system - hence I'll need to check carefully each row contains valid values before doing anything with it - and alert the user if anything is dodgy.
I suppose that the sorting (clicking a col hdr) will scrap my efforts to turn rows red, and I'll need to intercept some kind of "after sorting" event and re-do the red stuff?

Got it working, thanks.

Example: Add a column to a dataset read from XML, and check all rows for a bad field and set the new "Errors" field :

Code:

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        oDSet = New System.Data.DataSet
        oDSet.ReadXml(strFilePath)
        oDSet.Tables(0).Columns.Add("Errors")
        '  Show the col headings in the VS output pane
        'For Each col As System.Data.DataColumn In oDSet.Tables(0).Columns
        '    Console.WriteLine(col.ColumnName.ToString)
        'Next

        For Each drow As System.Data.DataRow In oDSet.Tables(0).Rows
            If drow.Item("SomeColumn").ToString = "Bad data" Then
                drow.Item("Errors") = "!" ' more user friendly instead : add description of problem :)
            End If
        Next

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Then it's a case of managing the DGV to set error rows red - this after-sort works for me

Code:

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    Private Sub DataGridView1_Sorted(sender As Object, e As System.EventArgs) Handles DataGridView1.Sorted
        For Each drow As System.Windows.Forms.DataGridViewRow In DataGridView1.Rows
            If drow.Cells("Errors").Value.ToString <> "" Then
                DataGridView1.Rows(drow.Index).DefaultCellStyle.BackColor = Color.Red
            End If
        Next
    End Sub

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- but the guts of that needs to be ripped out into a Sub that can be called when the grid is first shown, as well as when sorted and refreshed.

Is there really no more 'sticky' way to make row colours depend on row conditions?
Thanks