When doing a string comparison in C#, what is the difference between doing a
string test = "testvalue";
test.Equals("TESTVALUE", StringComparison.CurrentCultureIgnoreCase);
and
string test = "testvalue";
test.Equals("TESTVALUE", StringComparison.InvariantCultureIgnoreCase);
... and is it important to include that extra parameter, anyway?
Microsoft gives some decent guidance for when to use the InvariantCulture property:
MSDN: CultureInfo.InvariantCulture Property
... an application should use the invariant culture only for processes that require culture-independent results, such as formatting and parsing data that is persisted to a file. In other cases, it produces results that might be linguistically incorrect or culturally inappropriate.
Security Considerations
If a security decision will be made based on the result of a string comparison or case change, your application should use an ordinal comparison that ignores case instead of using InvariantCulture. [...]
String Operations
If your application needs to perform a culture-sensitive string operation that is not affected by the value of CurrentCulture, it should use a method that accepts a CultureInfo parameter. [...]
Persisting Data
The InvariantCulture property is useful for storing data that will not be displayed directly to users. Storing data in a culture-independent format guarantees a known format that does not change. When users from different cultures access the data, it can be formatted appropriately based on specific user. [...]