Importing CSV to DataGridView Error With CheckBox Column

Question

I have a DataGridView where I save the values to a CSV file. The code creates an empty value in the CSV where there is an empty cell in the DataGridView. The problem I have is with Column 10 in the DataGridView. This is a CheckBox column. The value of this column is “Nothing” unless it has been either checked or unchecked in which case the value becomes 0 or 1 (False or True).

When I load the CSV back into the DataGridView, if there is an empty value for the CheckBox Column I get an error. The DataGridView does not accept a “Nothing” value for this Column when importing from a CSV.

Is there a way to export the value of Column 10 only as 0 or 1?

Hoping someone can help me resolve this problem. Thanks in advance.

This is the code I use to Save the DataGridView to a CSV file.

        Dim rows = From row As DataGridViewRow In DataGridView1.Rows.Cast(Of DataGridViewRow)()
                   Where Not row.IsNewRow
                   Select Array.ConvertAll(row.Cells.Cast(Of DataGridViewCell).ToArray, Function(c) If(c.Value IsNot Nothing, c.Value.ToString, ""))
        Using sw As New IO.StreamWriter(Path)
            For Each r In rows
                sw.WriteLine(String.Join(",", r))
            Next
        End Using

And this is the code I use to load the CSV back into the DataGridView.

        Try
            Dim streamReader As IO.StreamReader = New IO.StreamReader(FullPath)
            'Read CSV file content 
            While streamReader.Peek() <> -1
                rowvalue = streamReader.ReadLine()
                cellvalue = rowvalue.Split(","c)
                    DataGridView1.Rows.Add(cellvalue)
            End While
            streamReader.Close()
        Catch ex As Exception
            MsgBox("File not found")
        End Try

Answer 1

If you don't want any empty values in that column then don't allow any. The simplest option for that is to set Value of the cell in that column to False when a row is added, if it's not already set to something else:

Private Sub DataGridView1_RowsAdded(sender As Object, e As DataGridViewRowsAddedEventArgs) Handles DataGridView1.RowsAdded
    Dim cell = DataGridView1.Rows(e.RowIndex).Cells(checkBoxColumnIndex)
    Dim value = cell.Value

    If value Is Nothing Then
        cell.Value = False
    End If
End Sub

With that, False effectively becomes the default value for that column. All your existing export and import code will just work.