ASP.NET CompareValidatorControl

Validation Server ControlsValidation Server Controls

Definition and Usage

The CompareValidator control is used to compare the value of an input control with the value of another input control or a constant value.

Note:If the input control is empty, no validation functions are called and validation will succeed. Use the RequiredFieldValidator control to make the field required.

Attributes

Attribute Description
BackColor The background color of the CompareValidator control.
ControlToCompare The name of the control to compare with the control being validated.
ControlToValidate The id of the control to validate.
Display The display behavior of the validation control. Legal values are:
  • None - The control is not displayed. It is only used to display error messages in the ValidationSummary control.
  • Static - If validation fails, the control displays an error message. Even if the input passes validation, space for displaying the message is reserved on the page, i.e., the space used to display the message is preallocated.
  • Dynamic - If validation fails, the control displays an error message. If the input passes validation, no space is reserved on the page for displaying the message, i.e., the space used to display the message is added dynamically.
EnableClientScript Boolean value that specifies whether client-side validation is enabled.
Enabled Boolean value that specifies whether the validation control is enabled.
ErrorMessage The text to display 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 The foreground color of the control.
id The unique id of the control.
IsValid Boolean value that indicates whether the control specified by ControlToValidate passes validation.
Operator The type of comparison operation to perform. Operators are:
  • Equal
  • GreaterThan
  • GreaterThanEqual
  • LessThan
  • LessThanEqual
  • NotEqual
  • DataTypeCheck
runat Specifies that the control is a server control. Must be set to "server".
Text The message displayed when validation fails.
Type Specifies the data type of the value to compare. Types are:
  • Currency
  • Date
  • Double
  • Integer
  • String
ValueToCompare A constant value to compare with the value entered by the user into the input control being validated.

Examples

CompareValidator
In this example, we declare two TextBox controls, a Button control, and a CompareValidator control in a .aspx file. If validation fails, the text "Validation Failed!" will be displayed in the CompareValidator control with a yellow background and red font.

CompareValidator 2
In this example, we declare two TextBox controls, a ListBox control, a Button control, and a CompareValidator control in a .aspx file. The check_operator() function sets the operator selected in the ListBox control as the operator of the CompareValidator control, and then validates the CompareValidator control. If validation fails, the text "Validation Failed!" will be displayed in the CompareValidator control with a yellow background and red font.

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