Simple C# Extension Method to truncate a string, preserving the last word.

We needed to truncate a summary down to n number of characters to provide a uniform look and feel.  So I whipped up this extension method to take the current string and truncate to n characters, attach an ellipsis to the end, and optionally keep the last word of the string preserved.  In other words, don’t chop the last word in half.

However, this is a very simple implementation.  There are a lot of things that we don’t consider here.  For example, we don’t consider the type of text.  If the text is HTML, we may leave it in a non-compliant state.  Or, if the initial truncated text ends in a period, we don’t leave it as is.  So there is a lot of room for improvement here.

Lastly, one thing I’m not doing is highlighting my code… the below sample code probably looks like crap inside this page.  I do have a syntax highlighter installed, but I don’t remember how to use it right now.  So I’ll fix that later if I remember.

Here is the code:

public static string Truncate(this string text, int length, string ellipsis, bool keepFullWordAtEnd)
    if (text.IsNullOrEmpty()) return string.Empty;
    if (text.Length < length) return text;
    text = text.Substring(0, length);
    if (keepFullWordAtEnd)
        text = text.Substring(0, text.LastIndexOf(' '));
    return text + ellipsis;
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