How can I limit a string to no more than a certain length? [duplicate]

Answer 1

Make sure that length won't exceed LongTitle (null checking skipped):

int maxLength = Math.Min(LongTitle.Length, 20);
string title = LongTitle.Substring(0, maxLength);

This can be turned into extension method:

public static class StringExtensions
{

    /// 

    /// Truncates string so that it is no longer than the specified number of characters.
    /// 
    /// String to truncate.
    /// Maximum string length.
    /// Original string or a truncated one if the original was too long.
    public static string Truncate(this string str, int length)
    {
        if(length < 0)
        {
            throw new ArgumentOutOfRangeException(nameof(length), "Length must be >= 0");
        }

        if (str == null)
        {
            return null;
        }

        int maxLength = Math.Min(str.Length, length);
        return str.Substring(0, maxLength);
    }
}

Which can be used as:

string title = LongTitle.Truncate(20);