How to Capitalize First Letter of First Name and Last Name in C#

How do I capitalize first letter of first name and last name in C#?

TextInfo.ToTitleCase() capitalizes the first character in each token of a string.

If there is no need to maintain Acronym Uppercasing, then you should include ToLower().

string s = "JOHN DOE";
s = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(s.ToLower());
// Produces "John Doe"

If CurrentCulture is unavailable, use:

string s = "JOHN DOE";
s = new System.Globalization.CultureInfo("en-US", false).TextInfo.ToTitleCase(s.ToLower());

See the MSDN Link for a detailed description.

Last name capitalization of first letter

This is a known issue with names - things are extremely inconsistent. Read this article for more information: http://www.w3.org/International/questions/qa-personal-names

In your example, you reference the last name "VAN BEBBER", which you want to be capitalized as "Van Bebber". However, as the article points out, there are other combinations from other areas of the world which would ruin most attempts at standardization - for instance, the last name "BIN OSMAN" would be properly capitalized as "bin Osman" - no capital "b" for "bin", which means "son of" and therefore doesn't fit well in the westernized concept of a last name.

You mention that you split last names by dashes, which most likely comes from the idea of a hyphenated last name - do you check the first name for dashes as well? The site gives the example name of "María-Jose Carreño Quiñones" - which is quite difficult to parse due to a double first name (separated by a hyphen) as well as a double last name (separated by a space). How would your program fair with that name?

To answer your question more directly, without bringing in more edge cases - you already know how to split a string via the dash - if you want to cover the case of last names with spaces, you should further split the last name string by spaces, and only then capitalize the first letter of the different split-up strings.

Alternatively, as Dai mentioned in a comment, you could use the ToTitleCase method - more information here: https://msdn.microsoft.com/en-us/library/system.globalization.textinfo.totitlecase(v=vs.110).aspx This is most likely a better solution than trying to make your own. However, this page references the fact that not all languages capitalize in the same way (and indeed, different last names may come from different areas/cultures/languages), and therefore setting the correct language may not always yield the correct last name capitalization. Note that it would capitalize "BIN OSMAN" as "Bin Osman", which is technically incorrect.

Here's a quick example from that page:

// Defines the String* with mixed casing.
String^ myString = "wAr aNd pEaCe";

// Creates a TextInfo based on the "en-US" culture.
/**** Personal Note - en-US may not be the correct culture for every last name! ****/
CultureInfo^ MyCI = gcnew CultureInfo( "en-US",false );
TextInfo^ myTI = MyCI->TextInfo;

// Changes a String* to lowercase. Outputs "War and Peace"
Console::WriteLine( "\"{0}\" to titlecase: {1}", myString, myTI->ToTitleCase( myString )

Issue in capitalizing first letter of first name and last name

ToTitleCase is an instance method so you have to call it with a reference to an instance of TextInfo. You can get an instance of TextInfo from the current thread's culture like this:

var textInfo = System.Threading.Thread.CurrentThread.CurrentCulture.TextInfo;

Or from a specific culture like this:

var textInfo = new CultureInfo("en-US",false).TextInfo;

Also, it returns a new string rather than modifying the string that you pass in. Try something like this instead:

public static UserAccount CreateUser(string firstName, string middleName, string lastName, string nameSuffix, int yearOfBirth, int? monthOfBirth, int? dayOfBirth, string email, string password, UserRole roles, bool tosAccepted = false)
{
    var textInfo = System.Threading.Thread.CurrentThread.CurrentCulture.TextInfo;

    var newUser = new UserAccount
    {
        CreationDate = DateTime.Now,
        ActivationCode = Guid.NewGuid(),
        FirstName = textInfo.ToTitleCase(firstName),
        MiddleName = middleName,
        LastName = textInfo.ToTitleCase(lastName),
        NameSuffix = nameSuffix,
        YearOfBirth = yearOfBirth,
        MonthOfBirth = monthOfBirth,
        DayOfBirth = dayOfBirth,
        Email = email,
        UserRoles = roles,
        ToSAccepted = tosAccepted
    };
    newUser.SetPassword(password);
    return newUser;
}

How to capitalize names

You can do this using the ToTitleCase method of the System.Globalization.TextInfo class:

CultureInfo cultureInfo = Thread.CurrentThread.CurrentCulture;
TextInfo textInfo = cultureInfo.TextInfo;

Console.WriteLine(textInfo.ToTitleCase(title));
Console.WriteLine(textInfo.ToLower(title));
Console.WriteLine(textInfo.ToUpper(title));

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 

How to get first character from firstName and lastName from Database and assign to object?

If you want the first initial and second initial I would suggest:

title = user.FirstName.FirstOrDefault().ToString()
    + user.LastName.FirstOrDefault().ToString(),

Since, user.FirstName.FirstOrDefault() returns the first character from the FirstName.

Make first letter of a string upper case (with maximum performance)

Solution in different C# versions

C# 8 with at least .NET Core 3.0 or .NET Standard 2.1

public static class StringExtensions
{
    public static string FirstCharToUpper(this string input) =>
        input switch
        {
            null => throw new ArgumentNullException(nameof(input)),
            "" => throw new ArgumentException($"{nameof(input)} cannot be empty", nameof(input)),
            _ => string.Concat(input[0].ToString().ToUpper(), input.AsSpan(1))
        };
}

Since .NET Core 3.0 / .NET Standard 2.1 String.Concat() supports ReadonlySpan<char> which saves one allocation if we use .AsSpan(1) instead of .Substring(1).

C# 8

public static class StringExtensions
{
    public static string FirstCharToUpper(this string input) =>
        input switch
        {
            null => throw new ArgumentNullException(nameof(input)),
            "" => throw new ArgumentException($"{nameof(input)} cannot be empty", nameof(input)),
            _ => input[0].ToString().ToUpper() + input.Substring(1)
        };
}

C# 7

public static class StringExtensions
{
    public static string FirstCharToUpper(this string input)
    {
        switch (input)
        {
            case null: throw new ArgumentNullException(nameof(input));
            case "": throw new ArgumentException($"{nameof(input)} cannot be empty", nameof(input));
            default: return input[0].ToString().ToUpper() + input.Substring(1);
        }
    }
}

Really old answers

public static string FirstCharToUpper(string input)
{
    if (String.IsNullOrEmpty(input))
        throw new ArgumentException("ARGH!");
    return input.First().ToString().ToUpper() + String.Join("", input.Skip(1));
}

This version is shorter. For a faster solution, take a look at Diego's answer.

public static string FirstCharToUpper(string input)
{
    if (String.IsNullOrEmpty(input))
        throw new ArgumentException("ARGH!");
    return input.First().ToString().ToUpper() + input.Substring(1);
}

Probably the fastest solution is Darren's (There's even a benchmark) although I would change it's string.IsNullOrEmpty(s) validation to throw an exception since the original requirement expects for a first letter to exist so it can be uppercased. Note that this code works for a generic string and not particularly on valid values from the Textbox.

Is there a CapitalizeFirstLetter method?

A simple extension method, that will capitalize the first letter of a string. As Karl pointed out, this assumes that the first letter is the right one to change and is therefore not perfectly culture-safe.

public static string CapitalizeFirstLetter(this String input)
{
    if (string.IsNullOrEmpty(input)) 
        return input;

    return input.Substring(0, 1).ToUpper(CultureInfo.CurrentCulture) +
        input.Substring(1, input.Length - 1);
}

You can also use System.Globalization.CultureInfo.CurrentCulture.TextInfo.ToTitleCase.
The function will convert the first character of each word to upper case. So if your input string is have fun the result will be Have Fun.

public static string CapitalizeFirstLetter(this String input)
{
     if (string.IsNullOrEmpty(input)) 
         return input;

     return CultureInfo.CurrentCulture.TextInfo.ToTitleCase(input);
}

See this question for more information.

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