The RequiredFieldValidator control is used to make an input control a required field.
With this control, the validation fails if the input value does not change from its initial value. By default, the initial value is an empty string ("").
Note: Leading and trailing spaces of the input value are removed before validation.
Note: The InitialValue property does not set the default value for the input control. It indicates the value that you do not want the user to enter in the input control.
Property | Description |
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BackColor | The background color of the RequiredFieldValidator control |
ControlToValidate | The id of the control to validate |
Display | The display behavior for the validation control. Legal values are:
|
EnableClientScript | A Boolean value that specifies whether client-side validation is enabled or not |
Enabled | A Boolean value that specifies whether the validation control is enabled or not |
ErrorMessage | The text to display in the ValidationSummary control when validation fails. Note: This text will also be displayed in the validation control if the Text property is not set |
ForeColor | The foreground color of the control |
id | A unique id for the control |
InitialValue | Specifies the starting value of the input control. Default value is "" |
IsValid | A Boolean value that indicates whether the control specified by ControlToValidate is determined to be valid |
runat | Specifies that the control is a server control. Must be set to "server" |
Text | The message to display when validation fails |
RequiredFieldValidator
Declare two TextBox controls, one Button control, and one RequiredFieldValidator control in an .aspx file. It
shows how to use the RequiredFieldValidator control to make the "txt_name" textbox a required field.