Conversion from string "0.##" to type 'Integer' is not valid

Question

i am doing a simple conversion from decimal to string and stripping trailing zeros like so:

argCat.ToString("0.##")

however, i keep getting the following error:

Conversion from string "0.##" to type 'Integer' is not valid.

am i missing something?

Answer 1

This would happen if argCat is of a type that does not have a ToString() overload that accepts a parameter.

In such a case, your code is parsed as ToString()("0.##"); the "0.##" becomes an argument to the indexer in the String returned by ToString().
You then get this misleading error because that indexer takes an int, not a string.

Answer 2

string str = String.Format("{0:C}", argCat);