Validating user control Teachers webcam chat

Posted by / 11-Oct-2017 10:59

Validating user control

You can validate the data as the data is entered in a control by reading the keys as they are pressed, or more commonly whenever the user takes the input focus away from one control and moves to the next.

This approach is useful when you want to give the user immediate feedback about the data as they are working.

If you want to use implicit validation for a control, you must set that control's Auto Validate property to .

If you cancel the Validating event, the behavior of the control will be determined by what value that you assigned to Auto Validate.

The masking language that is used by Masked Text Box is very flexible.

It allows you to specify required characters, optional characters, literal characters, such as hyphens and parentheses, currency characters, and date separators.

You may require that certain text fields not be zero-length, that a field be formatted as a telephone number or other type of well-formed data, or that a string not contain any unsafe characters that could be used to compromise the security of a database.

Windows Forms provides several ways for you to validate input in your application.

For a code example that validates an e-mail address in a Text Box, see Validating.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.Note that any control with Causes Validation set to False will not raise a Validating event and will therefore not be validated by Validate Children.When users enter data into your application, you may want to verify that the data is valid before your application uses it.

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If you assigned Enable Allow Focus Change, the Validated event will not occur when you cancel the event, but focus will still change to the next control.

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