The Trim method removes from the current string all leading and trailing white-space characters. Each leading and trailing trim operation stops when a non-white-space character is encountered. For example, if the current string is " abc xyz ", the Trim method returns "abc xyz".
This method does not modify the value of the current instance. Instead, it returns a new string in which all leading and trailing white space characters found in the current instance are removed.
If the current string equals Empty or all the characters in the current instance consist of white-space characters, the method returns Empty.
White-space characters are defined by the Unicode standard. The Trim() method removes any leading and trailing characters that produce a return value of true when they are passed to the Char.IsWhiteSpace method.
Notes to Callers
The .NET Framework 3.5 SP1 and earlier versions maintain an internal list of white-space characters that this method trims. Starting with the .NET Framework 4, the method trims all Unicode white-space characters (that is, characters that produce a true return value when they are passed to the Char.IsWhiteSpace method). Because of this change, the Trim method in the .NET Framework 3.5 SP1 and earlier versions removes two characters, ZERO WIDTH SPACE (U+200B) and ZERO WIDTH NO-BREAK SPACE (U+FEFF), that the Trim method in the .NET Framework 4 and later versions does not remove. In addition, the Trim method in the .NET Framework 3.5 SP1 and earlier versions does not trim three Unicode white-space characters: MONGOLIAN VOWEL SEPARATOR (U+180E), NARROW NO-BREAK SPACE (U+202F), and MEDIUM MATHEMATICAL SPACE (U+205F).