Note: Unless the browser does not support client-side validation or the EnableClientScript property is set to false, both server-side and client-side validation will be performed.

Note: If the input control is empty, validation will fail. Use the RequiredFieldValidator control to make the field required (mandatory).

Properties

Property	Description
BackColor	Background color of the RegularExpressionValidator control.
ControlToValidate	The id of the control to validate.
Display	The display behavior of the validation control. Valid values are: None - The control is not displayed. Used only to display error messages in the ValidationSummary control. Static - If validation fails, the control displays the error message. Even if input passes validation, space is reserved on the page to display the message, meaning the space for the message is pre-allocated. Dynamic - If validation fails, the control displays the error message. If input passes validation, no space is reserved on the page to display the message, meaning the space for the message is added dynamically.
EnableClientScript	Boolean value that specifies whether to enable client-side validation.
Enabled	Boolean value that specifies whether to enable the validation control.
ErrorMessage	The text displayed in the ValidationSummary control when validation fails. Note: If the Text property is not set, the text will also be displayed in the validation control.
ForeColor	Foreground color of the control.
id	The unique id of the control.
IsValid	Boolean value indicating whether the control specified by ControlToValidate has passed validation.
runat	Specifies that this control is a server control. Must be set to "server".
BackColor	Background color of the RegularExpressionValidator control.
Text	The message displayed when validation fails.
ValidationExpression	Specifies the regular expression to validate the input control. The syntax of the expression differs between client-side and server-side. JScript is used for client-side. On the server side, it uses the language you specify.

Examples

RegularExpressionValidator

In this example, we declared a TextBox control, a Button control, a Label control, and a RegularExpressionValidator control in the .aspx file. The submit() function checks if the page is valid. If it is valid, it returns "The page is valid!" in the Label control. If it is not valid, it returns "The page is not valid!" in the Label control. If validation fails, the text "The zip code must be 5 numeric digits!" will be displayed in the RegularExpressionValidator control.

Image 4: Validation Server Controls Validation Server Controls

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ASP.NET Web Server Controls

ASP.NET RequiredFieldValidator Control

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