Each control that I want to be validated, I have registered with the "validating" event. So basic question is, what is the best approach to validate a specific set of controls only when I want to and not when focus is lost from the control? The "Auto Validate" property is what I was looking for (found in link you provided).
EDIT: presently as a work around, I have a method that toggles the "Causes Validation" property on and off. It has to be set on the parent form and suppresses the validating event when a control is losing focus.
Maybe defer to a private method per control if the validation is complex.
3) If the control's content is not valid, pass it to the Error Provider's Set Error method along with your validation message.
This article was originally published in the "Chris Sells on . I don't mean don't trust them to pay (which is a completely separate issue that I won't go into here). For that, you need to handle a control's Validating event: The Validating will be called when moving focus from a control on the dialog that has the Causes Validation property set to true to another control that has the Causes Validation property set to true, e.g. The Validating event gives the handler the chance to cancel the move of focus by setting the Cancel Event Args. In this example, if the user doesn't enter a name into the text box, than the Validating event handler notifies the user of their transgression and cancels the event, which will keep the focus on the text box with invalid data.
However, sometimes you need to validate more free form data entry, like what a user types into a text box.
List boxes, radio buttons and all of the other controls that give users choices all do so to make sure that the provide data in the correct format.
If the Validating event is not canceled, the dialog will get notified with the Validated event: Since each control has Causes Validation set to true by default, to allow the user to cancel the dialog without entering valid data, make sure to set the Causes Validation property to false for your Cancel or Close button: As much as I lean on the message box in my test development, I prefer not to use it for actual applications.
Use this event to handle any needed upkeep after successfully validating the control.
If there is no problem, the error will be null, which will cause the error indicator on the dialog to go away.
A good user interface will validate user input to ensure it is in the correct format.
Each control has the following events and properties that are used to validate a form. Validation on a control is triggered when the control loses focus. Cancel Event Args] object as a parameter to the event block, which you can access this by using the in the Validating event, all events that would usually occur after the Validating event are suppressed.
Use this event to provide custom validation for any input control, such as a Text Box. In other words, the validating control will retain the focus until the user provides the correct format, even if the user clicks another control such as a button or textbox.