使字符串的第一个字母大写(以最大性能)

我有一个带有文本框的DetailsView 我希望输入的数据总是以大写的第一个字母保存。

例子:

"red" --> "Red"
"red house" --> " Red house"

我怎样才能实现性能最大化呢?

注意:

Based on the answers and the comments under the answers, many people think this is asking about capitalizing all words in the string. E.g. => Red House It isn't, but if that is what you seek, look for one of the answers that uses TextInfo's ToTitleCase method. (Note: Those answers are incorrect for the question actually asked.) See TextInfo.ToTitleCase documentation for caveats (doesn't touch all-caps words - they are considered acronyms; may lowercase letters in middle of words that "shouldn't" be lowered, e.g., "McDonald" → "Mcdonald"; not guaranteed to handle all culture-specific subtleties re capitalization rules.)

注意:

第一个字母之后的字母是否必须小写，这个问题很模糊。公认的答案假定只有第一个字母需要修改。如果要强制字符串中除第一个字母外的所有字母都小写，请查找包含ToLower且不包含ToTitleCase的答案。

当前回答

你可以使用“ToTitleCase方法”:

string s = new CultureInfo("en-US").TextInfo.ToTitleCase("red house");
//result : Red House

这种扩展方法解决了所有标题问题。

使用简单:

string str = "red house";
str.ToTitleCase();
//result : Red house

string str = "red house";
str.ToTitleCase(TitleCase.All);
//result : Red House

扩展方法:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;

namespace Test
{
    public static class StringHelper
    {
        private static CultureInfo ci = new CultureInfo("en-US");
        //Convert all first latter
        public static string ToTitleCase(this string str)
        {
            str = str.ToLower();
            var strArray = str.Split(' ');
            if (strArray.Length > 1)
            {
                strArray[0] = ci.TextInfo.ToTitleCase(strArray[0]);
                return string.Join(" ", strArray);
            }
            return ci.TextInfo.ToTitleCase(str);
        }

        public static string ToTitleCase(this string str, TitleCase tcase)
        {
            str = str.ToLower();
            switch (tcase)
            {
                case TitleCase.First:
                    var strArray = str.Split(' ');
                    if (strArray.Length > 1)
                    {
                        strArray[0] = ci.TextInfo.ToTitleCase(strArray[0]);
                        return string.Join(" ", strArray);
                    }
                    break;
                case TitleCase.All:
                    return ci.TextInfo.ToTitleCase(str);
                default:
                    break;
            }
            return ci.TextInfo.ToTitleCase(str);
        }
    }

    public enum TitleCase
    {
        First,
        All
    }
}

2013-04-06 12:30:46

其他回答

第一个字母和空格后面的每个字母都大写，其他字母都小写。

public string CapitalizeFirstLetterAfterSpace(string input)
{
    System.Text.StringBuilder sb = new System.Text.StringBuilder(input);
    bool capitalizeNextLetter = true;
    for(int pos = 0; pos < sb.Length; pos++)
    {
        if(capitalizeNextLetter)
        {
            sb[pos]=System.Char.ToUpper(sb[pos]);
            capitalizeNextLetter = false;
        }
        else
        {
            sb[pos]=System.Char.ToLower(sb[pos]);
        }

        if(sb[pos]=' ')
        {
            capitalizeNextLetter=true;
        }
    }
}

2010-11-09 15:43:54

string emp="TENDULKAR";
string output;
output=emp.First().ToString().ToUpper() + String.Join("", emp.Skip(1)).ToLower();

2013-05-02 11:47:14

最快的方法:

private string Capitalize(string s){
    if (string.IsNullOrEmpty(s))
    {
        return string.Empty;
    }
    char[] a = s.ToCharArray();
    a[0] = char.ToUpper(a[0]);
    return new string(a);
}

测试显示下一个结果(有1,000,000个符号作为输入的字符串):

测试结果

2016-04-13 04:33:16

我在c#大写首字母- Dot Net Perls中找到了一些东西:

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

    // Return char and concat substring.
    return char.ToUpper(s[0]) + s.Substring(1);
}

2014-05-27 12:06:55

FluentSharp有lowerCaseFirstLetter方法来做这个。

2015-07-21 17:25:20

使字符串的第一个字母大写(以最大性能)

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