Choose between two outputs based on whether a value matches a regular expression.

The Is Match formatter evaluates a regular expression against the placeholder value and outputs one of two formats. Apply it explicitly with the name . The expression goes in the options, in parentheses; the format provides the match output and the no-match output, separated by the split character. Both the match and no-match output are required.

To use braces and parentheses as character literals in your pattern, escape them with a backslash. For example, , , , .

You can configure settings on the formatter instance. Set the RegexOptions (for example, ) to control matching. Change the split character or the placeholder name for matches (the default is ). Refer to Configure Smart Strings for more information on formatter configuration.

The first format is used when the value matches; the second is used otherwise. You can output the regular expression's matching groups with a special placeholder named : is the whole match and , , and so on are the captured groups.

{0:ismatch(^.+123.+$):Okay - {}|No match content}

"Some123Content"

{0:ismatch(^.+123.+$):Fixed content if match|No match content}

"Some123Content"

{0:ismatch(^.+999.+$):{}|No match content}

"Some123Content"

{Currency:ismatch(\p{Sc}):Currency: {m[0]}|Unknown}

"€ Euro"

Combine it with the List formatter to test each item in a collection:

{0:list:{:ismatch(^100|200|999$):{:0.00}|'no match'}|, | and }

100, 200, 300