下面是一个逐字符的实现。它应该和"(一二三)"一起工作：

public static string ToInitcap(this string str)
{
    if (string.IsNullOrEmpty(str))
        return str;
    char[] charArray = new char[str.Length];
    bool newWord = true;
    for (int i = 0; i < str.Length; ++i)
    {
        Char currentChar = str[i];
        if (Char.IsLetter(currentChar))
        {
            if (newWord)
            {
                newWord = false;
                currentChar = Char.ToUpper(currentChar);
            }
            else
            {
                currentChar = Char.ToLower(currentChar);
            }
        }
        else if (Char.IsWhiteSpace(currentChar))
        {
            newWord = true;
        }
        charArray[i] = currentChar;
    }
    return new string(charArray);
}

就我个人而言，我尝试了TextInfo。ToTitleCase方法，但是，我不明白为什么当所有字符都是大写的时候它不起作用。

虽然我喜欢Winston Smith提供的util函数，但让我提供我目前正在使用的函数:

public static String TitleCaseString(String s)
{
    if (s == null) return s;

    String[] words = s.Split(' ');
    for (int i = 0; i < words.Length; i++)
    {
        if (words[i].Length == 0) continue;

        Char firstChar = Char.ToUpper(words[i][0]); 
        String rest = "";
        if (words[i].Length > 1)
        {
            rest = words[i].Substring(1).ToLower();
        }
        words[i] = firstChar + rest;
    }
    return String.Join(" ", words);
}

玩一些测试字符串:

String ts1 = "Converting string to title case in C#";
String ts2 = "C";
String ts3 = "";
String ts4 = "   ";
String ts5 = null;

Console.Out.WriteLine(String.Format("|{0}|", TitleCaseString(ts1)));
Console.Out.WriteLine(String.Format("|{0}|", TitleCaseString(ts2)));
Console.Out.WriteLine(String.Format("|{0}|", TitleCaseString(ts3)));
Console.Out.WriteLine(String.Format("|{0}|", TitleCaseString(ts4)));
Console.Out.WriteLine(String.Format("|{0}|", TitleCaseString(ts5)));

给输出:

|Converting String To Title Case In C#|
|C|
||
|   |
||

MSDN: TextInfo。ToTitleCase

确保你包括:使用系统。全球化

string title = "war and peace";

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

title = textInfo.ToTitleCase(title); 
Console.WriteLine(title) ; //War And Peace

//When text is ALL UPPERCASE...
title = "WAR AND PEACE" ;

title = textInfo.ToTitleCase(title); 
Console.WriteLine(title) ; //WAR AND PEACE

//You need to call ToLower to make it work
title = textInfo.ToTitleCase(title.ToLower()); 
Console.WriteLine(title) ; //War And Peace

String TitleCaseString(String s)
{
    if (s == null || s.Length == 0) return s;

    string[] splits = s.Split(' ');

    for (int i = 0; i < splits.Length; i++)
    {
        switch (splits[i].Length)
        {
            case 1:
                break;

            default:
                splits[i] = Char.ToUpper(splits[i][0]) + splits[i].Substring(1);
                break;
        }
    }

    return String.Join(" ", splits);
}

对于那些想要自动按下键盘的人，我用下面的VB代码做到了。NET在一个自定义文本框控件上-你显然也可以用一个普通的文本框来做-但是我喜欢通过自定义控件为特定控件添加循环代码的可能性，它适合OOP的概念。

Imports System.Windows.Forms
Imports System.Drawing
Imports System.ComponentModel

Public Class MyTextBox
    Inherits System.Windows.Forms.TextBox
    Private LastKeyIsNotAlpha As Boolean = True
    Protected Overrides Sub OnKeyPress(e As KeyPressEventArgs)
        If _ProperCasing Then
            Dim c As Char = e.KeyChar
            If Char.IsLetter(c) Then
                If LastKeyIsNotAlpha Then
                    e.KeyChar = Char.ToUpper(c)
                    LastKeyIsNotAlpha = False
                End If
            Else
                LastKeyIsNotAlpha = True
            End If
        End If
        MyBase.OnKeyPress(e)
End Sub
    Private _ProperCasing As Boolean = False
    <Category("Behavior"), Description("When Enabled ensures for automatic proper casing of string"), Browsable(True)>
    Public Property ProperCasing As Boolean
        Get
            Return _ProperCasing
        End Get
        Set(value As Boolean)
            _ProperCasing = value
        End Set
    End Property
End Class

试试这个:

string myText = "a Simple string";

string asTitleCase =
    System.Threading.Thread.CurrentThread.CurrentCulture.TextInfo.
    ToTitleCase(myText.ToLower());

如前所述，使用TextInfo。ToTitleCase可能不会给您想要的确切结果。如果你需要更多的输出控制，你可以这样做:

IEnumerable<char> CharsToTitleCase(string s)
{
    bool newWord = true;
    foreach(char c in s)
    {
        if(newWord) { yield return Char.ToUpper(c); newWord = false; }
        else yield return Char.ToLower(c);
        if(c==' ') newWord = true;
    }
}

然后像这样使用它:

var asTitleCase = new string( CharsToTitleCase(myText).ToArray() );