How to capitalize the first character of each word, or the first character of a whole string, with C#?

As discussed in the comments of @miguel's answer, you can use TextInfo.ToTitleCase which has been available since .NET 1.1. Here is some code corresponding to your example:

string lipsum1 = "Lorem lipsum et";

// Creates a TextInfo based on the "en-US" culture.
TextInfo textInfo = new CultureInfo("en-US",false).TextInfo;

// Changes a string to titlecase.
Console.WriteLine("\"{0}\" to titlecase: {1}", 
                  lipsum1, 
                  textInfo.ToTitleCase( lipsum1 )); 

// Will output: "Lorem lipsum et" to titlecase: Lorem Lipsum Et

It will ignore casing things that are all caps such as "LOREM LIPSUM ET" because it is taking care of cases if acronyms are in text so that "IEEE" (Institute of Electrical and Electronics Engineers) won't become "ieee" or "Ieee".

However if you only want to capitalize the first character you can do the solution that is over here… or you could just split the string and capitalize the first one in the list:

string lipsum2 = "Lorem Lipsum Et";

string lipsum2lower = textInfo.ToLower(lipsum2);

string[] lipsum2split = lipsum2lower.Split(' ');

bool first = true;

foreach (string s in lipsum2split)
{
    if (first)
    {
        Console.Write("{0} ", textInfo.ToTitleCase(s));
        first = false;
    }
    else
    {
        Console.Write("{0} ", s);
    }
}

// Will output: Lorem lipsum et 

If you just want to capitalize the first character, just stick this in a utility method of your own:

return string.IsNullOrEmpty(str) 
    ? str
    : str[0].ToUpperInvariant() + str.Substring(1).ToLowerInvariant();

There's also a library method to capitalize the first character of every word:

http://msdn.microsoft.com/en-us/library/system.globalization.textinfo.totitlecase.aspx

All the examples seem to make the other characters lowered first which isn't what I needed.

customerName = CustomerName <-- Which is what I wanted

this is an example = This Is An Example

public static string ToUpperEveryWord(this string s)
{
    // Check for empty string.  
    if (string.IsNullOrEmpty(s))
    {
        return string.Empty;
    }

    var words = s.Split(' ');

    var t = "";
    foreach (var word in words)
    {
        t += char.ToUpper(word[0]) + word.Substring(1) + ' ';
    }
    return t.Trim();
}

There is no prebuilt solution for proper linguistic captialization in .NET. What kind of capitialization are you going for? Are you following the Chicago Manual of Style conventions? AMA or MLA? Even plain english sentence capitalization has 1000's of special exceptions for words. I can't speak to what ruby's humanize does, but I imagine it likely doesn't follow linguistic rules of capitalization and instead does something much simpler.

Internally, we encountered this same issue and had to write a fairly large amount code just to handle proper (in our little world) casing of article titles, not even accounting for sentence capitalization. And it indeed does get "fuzzy" :)

It really depends on what you need - why are you trying to convert the sentences to proper capitalization (and in what context)?

I have achieved the same using custom extension methods. For First Letter of First sub-string use the method yourString.ToFirstLetterUpper(). For First Letter of Every sub-string excluding articles and some propositions, use the method yourString.ToAllFirstLetterInUpper(). Below is a console program:

class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("this is my string".ToAllFirstLetterInUpper());
            Console.WriteLine("uniVersity of lonDon".ToAllFirstLetterInUpper());
        }
    }

    public static class StringExtension
    {
        public static string ToAllFirstLetterInUpper(this string str)
        {
            var array = str.Split(" ");

            for (int i = 0; i < array.Length; i++)
            {
                if (array[i] == "" || array[i] == " " || listOfArticles_Prepositions().Contains(array[i])) continue;
                array[i] = array[i].ToFirstLetterUpper();
            }
            return string.Join(" ", array);
        }

        private static string ToFirstLetterUpper(this string str)
        {
            return str?.First().ToString().ToUpper() + str?.Substring(1).ToLower();
        }

        private static string[] listOfArticles_Prepositions()
        {
            return new[]
            {
                "in","on","to","of","and","or","for","a","an","is"
            };
        }
    }

OUTPUT

This is My String
University of London
Process finished with exit code 0.

Far as I know, there's not a way to do that without writing (or cribbing) code. C# nets (ha!) you upper, lower and title (what you have) cases:

http://support.microsoft.com/kb/312890/EN-US/