最好通过尝试自己的代码来理解…

阅读更多

http://www.stupidcodes.com/2014/04/convert-string-to-uppercase-proper-case.html

1)将字符串转换为大写

string lower = "converted from lowercase";
Console.WriteLine(lower.ToUpper());

2)将字符串转换为小写

string upper = "CONVERTED FROM UPPERCASE";
Console.WriteLine(upper.ToLower());

3)转换String为TitleCase

    CultureInfo cultureInfo = Thread.CurrentThread.CurrentCulture;
    TextInfo textInfo = cultureInfo.TextInfo;
    string txt = textInfo.ToTitleCase(TextBox1.Text());

如果有人对Compact Framework的解决方案感兴趣:

return String.Join(" ", thestring.Split(' ').Select(i => i.Substring(0, 1).ToUpper() + i.Substring(1).ToLower()).ToArray());

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

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);
}

这是另一种变化。基于这里的几个技巧，我将其简化为以下扩展方法，它非常适合我的目的:

public static string ToTitleCase(this string s) =>
    CultureInfo.InvariantCulture.TextInfo.ToTitleCase(s.ToLower());

public static string PropCase(string strText)
{
    return new CultureInfo("en").TextInfo.ToTitleCase(strText.ToLower());
}