BindingNavigator and the BindingSource that it wraps do not offer validation and/or navigation cancellation mechanisms.

The closer validation happens to where data is being edited the more information your app has about what caused the data to become invalid.

In the case of simple binding (for instance, if your form contains text boxes bound to a data source ) then you can use the Control::Validating event to validate and possibly cancel navigation.

If your app contains a data grid view bound to a data table then you can use DataGridView::CellValidating event or DataGridView::RowValidatingEvent.

Hope this helps,
Daniel.

It's possible to have a form where you can't validate just a single control. A simple example;

Date Event Reported to Agency x:

Reason not reported:

One of them, and only one needs a value. You can't validate them during control validation, because if the user tabs into one, and they're both blank (because it's a new event), he can't tab out until he pust something in, whether correct or not.

Being able to cancel navigation would make this sort of case a lot easier.

if you are using buttons to move first, next, or previous then on the click event of the button check the rowstate of the current row ; newly added row will have a rowstate of Detached, if you call the endEdit method of your binding source then the rowstate will be Added

if you modify the record by changing the value in a data-bound text box then the rowState will be Modified

so in the click event of your button:

if((DataRowView)this.Bs.Current).Row.RowState == DataRowState.Added ||

(DataRowView)this.Bs.Current).Row.RowState == DataRowState.Detached ||

(DataRowView)this.Bs.Current).Row.RowState == DataRowState.Modified)

{

//prompt the user to save or cancel the changes made

//if canceled then bs.MoveNext

}

//note Bs is your binding source