Triming strings to whole words in C#

This is a method that I have found useful whilst having to trim a string to a number of chars, whilst keeping whole words.

public string TrimToNumberOfChars (string originalString, int maxChar)
{
    if (originalString.Length <= maxChar)         
        return originalString;      
   
    int lastSpace = originalString.LastIndexOf(" ", maxChar - 1);     
    if (lastSpace == -1) return "";      
        return originalString.Substring(0, lastSpace) + "..."; 
} 

I hope other people find this useful.