I have two regular expression.
[RegularExpression(@".*[^ ].*", ErrorMessage ="Something")]validate string that only contains spaces(Not any other characters Ex:" ".length = 7).[RegularExpression(@"^[^~!@#$%&*]+$", ErrorMessage = "something")]validate string that contains~!@#$%&*special characters.
How can I combine both regex into one, because Duplicate Regular expression annotation is not allowed in asp.net mvc.
You may use
^[^~!@#$%&*]*[^~!@#$%&*\s][^~!@#$%&*]*$
See the regex demo
Details
^- start of string[^~!@#$%&*]*- 0+ chars other than a char in the~!@#$%&*list[^~!@#$%&*\s]- a char other than a char in the~!@#$%&*list and whitespace[^~!@#$%&*]*- 0+ chars other than a char in the~!@#$%&*list$- end of string.
NOTE: To also allow an empty string you need to wrap the pattern between the anchors within an optional group: ^(?:[^~!@#$%&*]*[^~!@#$%&*\s][^~!@#$%&*]*)?$.
来源：https://stackoverflow.com/questions/54780873/combine-two-regular-expression-into-one-while-validating-attribute