Net textbox validating
If not to prevent the focus change then at least for the Causes Validation property.Which you set to False on, say, the Cancel button of a dialog.If you do not set the Cancel property, Windows Forms will assume that validation succeeded for that control, and raise the Validated event.For a code example that validates an email address in a Text Box, see Validating.No point in validating anything when the user decides to dismiss the dialog.When users enter data into your application, you may want to verify that the data is valid before your application uses it.This would initially make me think I would rather use the Leave event, as it occurs first.However, for code readability, it would make sense to place all validation code in the Validating event.
Printing Public Class Main Class Shared Sub Main() Dim form1 As Form = New Form1() Application. Initialize Component() 'Add any initialization after the Initialize Component() call End Sub 'Form overrides dispose to clean up the component list.
Validation is very useful when you have bound your controls to a data source, such as a database table.
By using validation, you can make sure that your control's data satisfies the format required by the data source, and that it does not contain any special characters such as quotation marks and back slashes that might be unsafe.
When you use data binding, the data in your control is synchronized with the data source during execution of the Validating event.
If you cancel the Validating event, the data will not be synchronized with the data source.