[ms-xlsx]: Excel (. xlsx) Extensions to the Office Open xml spreadsheetml file Format

operator: An ST_DataValidationOperator ([ISO/IEC29500-1:2011] section 18.18.20) attribute that specifies the relational operator used with this data validation. If type is "custom", "list", or "none", the value of the operator attribute is undefined and MUST be ignored.

allowBlank: A Boolean ([XMLSCHEMA2] section 3.2.2) attribute that specifies whether the data validation treats empty or blank entries as valid.

Value	Meaning
"true"	The data validation treats empty or blank entries as valid.
"false"	The data validation treats empty or blank entries as invalid.

showDropDown: A Boolean ([XMLSCHEMA2] section 3.2.2) attribute that specifies whether to display the drop-down combo box for a list type data validation.

Value of showDropDown	Value of type	Meaning
"true"	list	Displays the drop-down combo box.
"false"	list	Suppresses the drop-down combo box.

showInputMessage: A Boolean ([XMLSCHEMA2] section 3.2.2) attribute that specifies whether to display the input prompt message.

Value	Meaning
"true"	Display the input prompt message.
"false"	Suppress the input prompt message.

showErrorMessage: A Boolean ([XMLSCHEMA2] section 3.2.2) attribute that specifies whether to display the error alert message.

Value	Meaning
"true"	Display the error alert message.
"false"	Suppress the error alert message.

errorTitle: An ST_Xstring ([ISO/IEC29500-1:2011] section 22.9.2.19) attribute that specifies the text of the title bar of the error alert. The length of this string MUST be less than or equal to 32 characters.

error: An ST_Xstring attribute that specifies the message text of the error alert. The length of this string MUST be less than or equal to 225 characters.

promptTitle: An ST_Xstring attribute that specifies the text of the title bar of the input prompt. The length of this string MUST be less than or equal to 32 characters.