Let’s assume when we click our save button that we wish to validate the controls and display an icon if there is a problem.
First, add the following code to the Form’s constructor after the Initialize Component method: This is a handy trick to prevent implicit validation of our controls when they lose focus.
is changed to “invalid” so a screen reader can notify the screen reader user.
I am trying to figure out how to require that a Single Line Textbox is not empty on form submission.
If there is no problem, the error will be null, which will cause the error indicator on the dialog to go away.
That means the user cannot close the form unless the field passes validation.
Note also that the user can leave a field if it doesn’t have a This entry was posted in controls and tagged C#, C# programming, controls, example, example program, validate field, validate form, Validating event, Windows Forms programming.
Now you can explore these areas and comment here in case of any issues.
-like widget that checks to make sure the user’s input is valid (according to a specified criterion).