Form validating event
The following code example uses the derived class Text Box and validates an email address that the user enters. Length) ' Set the Error Provider error with the text to display. Set Error(text Box1, error Msg) End If End Sub Private Sub text Box1_Validated(By Val sender As Object, _ By Val e As System. Validated ' If all conditions have been met, clear the error provider of errors. Set Error(text Box1, "") End Sub When you change the focus by using the keyboard (TAB, SHIFT TAB, and so on), by calling the Select or Select Next Control methods, or by setting the Container Control.
If the email address is not in the standard format (containing "@" and "."), the validation fails, an Error Provider icon is displayed, and the event is canceled. Active Control property to the current form, focus events occur in the following order: Caution Do not attempt to set focus from within the Enter, Got Focus, Leave, Lost Focus, Validating, or Validated event handlers.
See rules() for more details about specifying validation rules.
Use error Class, error Element, wrapper, error Label Container, error Container, show Errors, success, error Placement, highlight, unhighlight, and ignore Title to control how invalid elements and error messages are displayed.
This example requires that a Text Box and Error Provider control have been created on a form. Index Of("@")) Then error Message = "" Return True End If End If error Message = "Email address must be valid email address format." Control Chars. Validating Dim error Msg As String If Not Valid Email Address(text Box1. Doing so can cause your application or the operating system to stop responding.
private: void text Box1_Validating( Object^ sender, System:: Component Model:: Cancel Event Args^ e ) void text Box1_Validated( Object^ sender, System:: Event Args^ e ) public: bool Valid Email Address( String^ email Address, [Out]interior_ptrprivate void text Box1_Validating(object sender, System. Cancel Event Args e) private void text Box1_Validated(object sender, System. Length = 0 Then error Message = "Email address is required." Return False End If ' Confirm that there is an "@" and a "." in the email address, and in the correct order. Cr _ "For example '[email protected]' " Return False End Function Private Sub text Box1_Validating(By Val sender As Object, _ By Val e As System. Text, error Msg) Then ' Cancel the event and select the text to be corrected by the user.
focus Invalid focuses elements when submitting an invalid form.
If the entered data follows all of the specified rules, it is considered valid; if not, it is considered invalid.
One of the features of HTML5 is the ability to validate most user data without relying on scripts.
This is done by using validation attributes on form elements.
Active Control property to the current form, focus events occur in the following order Enter Got Focus Leave Validating Validated Lost Focus When you change the focus by using the mouse or by calling the Focus method, focus events occur in the following order: Enter Got Focus Lost Focus Leave Validating Validated event provides the hook to perform the validation and Error Provider gives a nice consistent approach to providing the user with feedback on any error conditions.
And, what should be Datasource Update Mode- On Property Changed or On Validation?