input.Remove(input.IndexOf(')')).Substring(input.IndexOf('(') + 1);

也许是正则表达式?我认为这行得通……

\(([a-z]+?)\)

using System;
using System.Text.RegularExpressions;

private IEnumerable<string> GetSubStrings(string input, string start, string end)
{
    Regex r = new Regex(Regex.Escape(start) +`"(.*?)"`  + Regex.Escape(end));
    MatchCollection matches = r.Matches(input);
    foreach (Match match in matches)
    yield return match.Groups[1].Value;
}

正则表达式可能是这里最好的工具。如果你不熟悉它们，我建议你安装Expresso -一个很棒的小正则表达式工具。

喜欢的东西:

Regex regex = new Regex("\\((?<TextInsideBrackets>\\w+)\\)");
string incomingValue = "Username (sales)";
string insideBrackets = null;
Match match = regex.Match(incomingValue);
if(match.Success)
{
    insideBrackets = match.Groups["TextInsideBrackets"].Value;
}

一个非常简单的方法是使用正则表达式:

Regex.Match("User name (sales)", @"\(([^)]*)\)").Groups[1].Value

作为对(非常有趣的)评论的回应，这里是同一个正则表达式的一些解释:

\(             # Escaped parenthesis, means "starts with a '(' character"
    (          # Parentheses in a regex mean "put (capture) the stuff 
               #     in between into the Groups array" 
       [^)]    # Any character that is not a ')' character
       *       # Zero or more occurrences of the aforementioned "non ')' char"
    )          # Close the capturing group
\)             # "Ends with a ')' character"

如果你想远离正则表达式，我能想到的最简单的方法是:

string input = "User name (sales)";
string output = input.Split('(', ')')[1];