More About Validation-Control Tag Attributes

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6.4.1 More About Validation-Control Tag Attributes

In addition to the attributes supported by all web controls, the validation controls recognize the following attributes within their respective tags: ControlToValidate Represents the name of the control to validate, as given by the controls ID property. Display Specifies whether visual space for the error message should be reserved on the web page, even if the message isnt currently being displayed. The possible values are: Dynamic Space for the error message is added to the page if validation fails. Static Space for the error message is added to the page, regardless of whether the message is actually displayed. This is the default. None The error message is never displayed, even if validation fails. This setting is used when the error message is displayed only in a validation summary control. EnableClientSideScript Specifies whether to enable client-side validation if supported by the browser. The default is True . ErrorMessage Provides the message displayed to the user if validation fails. The default is an empty string. ForeColor Defines the color in which the error message is displayed. The default is Red . Valid values for this attribute are given by the Color structure defined in the System.Drawing namespace. See Chapt er 4 for information about the Color structure. The CompareValidator control recognizes these additional attributes: ControlToCompare The name of the control that contains the value to compare. If this attribute is specified, the ValueToCompare attribute should not be specified. Operator The comparison to be performed. The possible values are: DataTypeCheck 276 Validation succeeds if the value in the control to validate can convert to the type specified by the Type attribute. Equal Validation succeeds if the value in the control to validate is equal to the comparison value. GreaterThan Validation succeeds if the value in the control to validate is greater than the comparison value. GreaterThanEqual Validation succeeds if the value in the control to validate is greater than or equal to the comparison value. LessThan Validation succeeds if the value in the control to validate is less than the comparison value. LessThanEqual Validation succeeds if the value in the control to validate is less than or equal to the comparison value. NotEqual Validation succeeds if the value in the control to validate is not equal to the comparison value. Type The data type of the values being compared. The values are converted to this type before the comparison is made. The possible values are Currency , Date , Double , Integer , and String . ValueToCompare The value to use for comparison. If this attribute is specified, the ControlToCompare attribute should not be specified. The CustomValidator control recognizes this additional attribute: ClientValidationFunction The name of the client-side script function to call to perform client-side validation. Server-side custom validation is performed by responding to the CustomValidator controls ServerValidate event. See Sect ion 6.4.4 later in this chapter for details. The RangeValidator control recognizes these additional attributes: MaximumValue The maximum value of the range. The default is an empty string. 277 MinimumValue The minimum value of the range. The default is an empty string. Type The data type of the value being validated. The value being validated, as well as the maximum and minimum values, are all converted to this type before the comparisons are made. The possible values are Currency , Date , Double , Integer , and String . The default is String . The RegularExpressionValidator control recognizes this additional attribute: ValidationExpression The regular expression against which to validate. The RequiredFieldValidator control recognizes this additional attribute: InitialValue The value considered a blank value. The default is an empty string. Validation fails if and only if the value in the control to be validated matches the value given in the InitialValue attribute.

6.4.2 Using Validation-Control Properties