Question

I have the following method but it fails if the string is null. How could I make it just return a null if the string is null?

public static string Truncate(this string value, int maxChars)
{
    return value.Length <= maxChars ?
           value :
           value.Substring(0, maxChars) + " ..";
}

Could someone also explain to me what the “this” is there for. Sorry I’m not so good at C# and this is not my code.

Answer 1

By checking for null and returning appropriately 🙂

public static string Truncate(this string value, int maxChars)
{
    if (value == null)
    {
        return null;
    }
    return value.Length <= maxChars ?
           value : value.Substring(0, maxChars) + " ..";
}

Or you could even use another conditional:

public static string Truncate(this string value, int maxChars)
{
    return value == null ? null
        : value.Length <= maxChars ? value 
        : value.Substring(0, maxChars) + " ..";
}