=>Difference between these two( "" & String.Empty)

String.Empty is a read-only static field in the System.String class which is set to the empty string "". The assignment takes place when a string is first referenced in your program.

Consequently, there's virtually no difference in using this field or the empty string "" directly and, personally, I nearly always use the latter as it's easier to write.

Note though that if you're testing whether a string is empty or not, then it's more performant to check whether the Length property is zero.

So, instead of this:

if (s == String.Empty)

// or this

if (s == "")

// this is quicker

if (s.Length == 0)

In practice, of course, unless you're doing thousands of such tests, the performance improvement will be negligible.