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David Hooley
295
Setting value of decimal cell to ""
posted

I'm trying to add some validation into my UltraGrid, whereby, if the user types a value into one cell, but has not set the value of a CheckBoxColumn to True, a MessageBox gets displayed and the text/value in that cell is cleared, leaving a blank cell again.

What I have so far in the CellChange method is:

Try
  If e.Cell.Column.Key = "Commission_Rate" Then
   If e.Cell.Row.Cells("Commission_Override").Value = False Then
    MessageBox.Show("Before entering a custom rate, please set 'Commission Override' to True", "Override Commission", MessageBoxButtons.OK)
    e.Cell.Value = DBNull.Value
   End If
  End If
Catch
End Try

However, that doesn't update the value until closing the MessageBox, and then setting the CheckBoxColumn to True. Only when that has been done will it set the value to ""/clear the entered text.

My guess is that is's something to do with the value and text being different, but I may be wrong.

How do I modify the code to set the value to nothing/null without having to change another cell value first?

  • 21795
    Verified Answer
    Offline posted

    Hello David,

    If you need to validate the user input you may handle BeforeEnterEditMode event of the grid. In this event you can check if the corresponding check box is checked. If not cancel the event and the cell will not enter in edit mode. This will suppress the user to enter any input in the cell and the cell will retain its initial value, whatever it was. You can use code like this:

    Private Sub UltraGrid1_BeforeEnterEditMode(sender As Object, e As System.ComponentModel.CancelEventArgs) Handles UltraGrid1.BeforeEnterEditMode
        Dim activeCell As UltraGridCell = Me.UltraGrid1.ActiveCell
        If activeCell Is Nothing Then
            Return
        End If
        Try
            If activeCell.Column.Key = "Commission_Rate" Then
                If activeCell.Row.Cells("Commission_Override").Value = False Then
                    MessageBox.Show("Before entering a custom rate, please set 'Commission Override' to True", "Override Commission", MessageBoxButtons.OK)
     
                    ' Cancel the event to disallow cell to enter edit mode. This will prevent user to type any value in the cell
                    ' and will retain the cell's original value
                    e.Cancel = True
                End If
            End If
        Catch
        End Try
    End Sub

    Attached is a small sample showing this approach. Please, check my sample and let us know if any additional questions arise.

    UltraGridWrongValue.zip