Custom textbox validating user input
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.
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.
To validate your controls, you will have to use explicit validation.
Assigning Disable to the Auto Validate property prevents implicit validation altogether.In this case, to perform validation in the Validated event, change the control's Data Source Update Mode property (under (Databindings)\(Advanced)) from On Validation to Never, and add So when does a control's data get validated? You can use either implicit or explicit validation, depending on the needs of your application.The implicit validation approach validates data as the user enters it.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.
The masking language that is used by Masked Text Box is very flexible.