Setting Min Value of a Date cell of UltraWinGrid

Question

I have an UltraWinGrid in one of my forms that is used for the user to enter VAT rates into. There are 3 columns:

• Rate
• Date From
• Date To

I need to validate the grid so that if there is a value entered in the "Date From" cell of a row, the user can only enter a minimum value of the "Date From" value + 1 day.

In which method would this go? And how do I do it?

I have tried doing

Private Sub ugVatRates_BeforeCellActivate(sender As Object, e As CancelableCellEventArgs) Handles ugVatRates.BeforeCellActivate

 Dim dateFrom As Date

 If IsDBNull(e.Cell.Row.Cells("DateFrom").Value) = False OrElse e.Cell.Row.Cells("DateFrom").Value <> Nothing Then
   dateFrom = e.Cell.Row.Cells("DateFrom").Value
   e.Cell.Row.Cells("DateTo").MinValue = dateFrom.AddDays(1)
End If

End Sub

However, MinValue is not a valid property here - Any advice?

Answer 1

Yes, MinValue and MaxValue are only exposed by UltraGridColumn. However, this will not work in your case. What you can do is handle BeforeCellUpdate event. In this event check if the cell user tries to update is DateTo cell as well as in DateFrom has value. If so you may suppress accepting of the new value by setting e.Cancel to true like this:

    Private Sub ugVatRates_BeforeCellActivate(sender As Object, e As Infragistics.Win.UltraWinGrid.BeforeCellUpdateEventArgs) Handles ugVatRates.BeforeCellUpdate
    If e.Cell.Column.Header.Caption = "DateTo" Then
        Dim dateFrom As Date
        Dim dateTo As Date

        If IsDBNull(e.Cell.Row.Cells("DateFrom").Value) = False OrElse e.Cell.Row.Cells("DateFrom").Value <> Nothing Then
            dateFrom = e.Cell.Row.Cells("DateFrom").Value
            dateTo = Date.Parse(e.Cell.Row.Cells("DateTo").Text)
            If dateTo < dateFrom.AddDays(1) Then
                ' Suppress accepting of new value 
                e.Cancel = True
            End If
        End If
    End If
End Sub

When the user enters invalid date you may show a message box to inform him, or use UltraGrid's Data Validation.