Exclusive RequiredFieldValidation among multiple Textboxes

I'm developing a web form which consists of a set of TextBoxes, as per the system requirements, the users are requested to fill-up AT LEAST ONE of those TextBoxes. If RequiredFieldValidation is used, how can I achieve such requirement? Please kindly advis开发者_开发知识库e.

Thank you very much! William

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You can use CustomValidator, you can refer to this question:

asp.net validate textbox - at least one text box must have data in