SOLUTION To achieve data validation prior the row is committed, you can handle the Cell Validating event, which is raised by the control when the current cell changes or when it goes out of edit mode.Canceling this event prevents the user from exiting the cell until a valid value is entered or the edit process is canceled (via Esc key). Is In Edit Mode Then Dim c As Control = Data Grid View1. provides a convenient way to realize data validation before it is committed to the underlying data source.See the image the information is provided there..., which are in blue color they are readonly ......
This funtionality can be easily implemented by handling the Preview Key Down event, which will revert the row changes after pressing the Esc key.
However, pressing the Esc key in this situation will revert the initial value of the cell and it will close the editor. The Row Validating event has a slightly different behavior.
When the validation fails, the editor is closed, but the user cannot change the current row in the grid until a valid cell value is entered.
Form Private With Events data Grid View1 As New Data Grid View() Private binding Source1 As New Binding Source() Public Sub New() ' Initialize the form.
Cell Validating Dim header Text As String = _ data Grid View1.