Start Datagridview cellvalidating value

Datagridview cellvalidating value

Hovering the mouse pointer on the icon displays the Error Text that you set earlier.

1) Add a conditional statement in the event handler code to only execute when required.

There are two flavors, passive and supervising controller.

The very first thing you need to do is make sure that your form is not responsible for retrieving the Data Table. The Presenter should be responsible for providing it to the View.

Set the Error Text property on the row to an explanatory string.

This displays an error icon with a Tool Tip that contains the error text.

I would suggest that you start writing your tests first, for now at least.

The benefit there is that you have to design your code to be testable to begin with.

To perform any custom validation on the cell or row being edited, you can use the Cell Validating and Row Validation events, respectively.