The System.Text.RegularExpressions.Regex class maintains an internal cache of compiled regular expressions used in static method calls. If the value specified in a set operation is less than the current cache size, cache entries are discarded until the cache size is equal to the specified value.

By default, the cache holds 15 compiled static regular expressions. Your application typically will not have to modify the size of the cache. Use the Regex.CacheSize property only when you want to turn off caching or when you have an unusually large cache.

Namespace: System.Text.RegularExpressions
Assembly: System (in System.dll)
Assembly Versions: 2.0.0.0, 4.0.0.0