下面是这个问题的解决方案……

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

不使用TextInfo:

public static string TitleCase(this string text, char seperator = ' ') =>
  string.Join(seperator, text.Split(seperator).Select(word => new string(
    word.Select((letter, i) => i == 0 ? char.ToUpper(letter) : char.ToLower(letter)).ToArray())));

它循环每个单词中的每个字母，如果它是第一个字母，则将其转换为大写字母，否则将其转换为小写字母。

试试这个:

using System.Globalization;
using System.Threading;
public void ToTitleCase(TextBox TextBoxName)
        {
            int TextLength = TextBoxName.Text.Length;
            if (TextLength == 1)
            {
                CultureInfo cultureInfo = Thread.CurrentThread.CurrentCulture;
                TextInfo textInfo = cultureInfo.TextInfo;
                TextBoxName.Text = textInfo.ToTitleCase(TextBoxName.Text);
                TextBoxName.SelectionStart = 1;
            }
            else if (TextLength > 1 && TextBoxName.SelectionStart < TextLength)
            {
                int x = TextBoxName.SelectionStart;
                CultureInfo cultureInfo = Thread.CurrentThread.CurrentCulture;
                TextInfo textInfo = cultureInfo.TextInfo;
                TextBoxName.Text = textInfo.ToTitleCase(TextBoxName.Text);
                TextBoxName.SelectionStart = x;
            }
            else if (TextLength > 1 && TextBoxName.SelectionStart >= TextLength)
            {
                CultureInfo cultureInfo = Thread.CurrentThread.CurrentCulture;
                TextInfo textInfo = cultureInfo.TextInfo;
                TextBoxName.Text = textInfo.ToTitleCase(TextBoxName.Text);
                TextBoxName.SelectionStart = TextLength;
            }
        }

在TextBox的TextChanged事件中调用此方法。

C语言的一种方法:

char proper(char string[])
{
    int i = 0;

    for(i=0; i<=25; i++)
    {
        string[i] = tolower(string[i]);  // Converts all characters to lower case
        if(string[i-1] == ' ') // If the character before is a space
        {
            string[i] = toupper(string[i]); // Converts characters after spaces to upper case
        }
    }

    string[0] = toupper(string[0]); // Converts the first character to upper case
    return 0;
}

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());

作为扩展方法:

/// <summary>
//     Returns a copy of this string converted to `Title Case`.
/// </summary>
/// <param name="value">The string to convert.</param>
/// <returns>The `Title Case` equivalent of the current string.</returns>
public static string ToTitleCase(this string value)
{
    string result = string.Empty;

    for (int i = 0; i < value.Length; i++)
    {
        char p = i == 0 ? char.MinValue : value[i - 1];
        char c = value[i];

        result += char.IsLetter(c) && ((p is ' ') || p is char.MinValue) ? $"{char.ToUpper(c)}" : $"{char.ToLower(c)}";
    }

    return result;
}

用法:

"kebab is DELICIOU's   ;d  c...".ToTitleCase();

结果:

Kebab Is Deliciou's;d C…