ASP.NET CustomValidator Control
Definition and Usage
The CustomValidator control can perform user-defined validation on input controls.
Property
| Property | Description |
|---|---|
| BackColor | Background color of the CustomValidator control. |
| ClientValidationFunction |
Specifies the name of the custom client script function used for validation. Note: The script must be written in a language supported by the browser, such as VBScript or JScript If using VBScript, the function must be located within the form: Sub FunctionName (source, arguments) If using JScript, the function must be located within the form: Function FunctionName (source, arguments) |
| ControlToValidate | The id of the input control to be validated. |
| Display |
The display behavior of error information in the validation control. Valid values include:
|
| EnableClientScript | Boolean value indicating whether client-side validation is enabled. |
| Enabled | Boolean value indicating whether the validation control is enabled. |
| ErrorMessage |
Text of the error information displayed in the ValidationSummary control when validation fails. Note: If the ErrorMessage property is set but the Text property is not set, the ErrorMessage property value will also be displayed in the validation control. |
| ForeColor | The foreground color of the control. |
| id | The unique id of the control. |
| IsValid | Boolean value indicating whether the associated input control passes validation. |
| OnServerValidate | Specifies the name of the server-side validation script function to be executed. |
| runat | Specifies that the control is a server control. It must be set to "server". |
| Text | Text displayed when validation fails. |
Instance
- CustomValidator
- In this example, we declared two Label controls, one TextBox control, one Button control, and one CustomValidator control in the .aspx file. The user() function can detect the length of the input value. If the length is less than 8 or greater than 16, the text "The username must be between 8 and 16 characters!" will be displayed in the CustomValidator control.
