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。
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
}
}
我从c#大写首字母- Dot Net Perls中获得了最快的方法，并将其转换为扩展方法:
/// <summary>
/// Returns the input string with the first character converted to uppercase, or mutates any nulls passed into string.Empty
/// </summary>
public static string FirstLetterToUpperCaseOrConvertNullToEmptyString(this string s)
{
if (string.IsNullOrEmpty(s))
return string.Empty;
char[] a = s.ToCharArray();
a[0] = char.ToUpper(a[0]);
return new string(a);
}
注意:使用ToCharArray比替代char.ToUpper(s[0]) + s.Substring(1)更快的原因是只分配了一个字符串，而Substring方法为子字符串分配了一个字符串，然后再分配一个字符串来组成最终结果。
下面是这种方法的样子，结合CarlosMuñoz接受的答案的初始测试:
/// <summary>
/// Returns the input string with the first character converted to uppercase
/// </summary>
public static string FirstLetterToUpperCase(this string s)
{
if (string.IsNullOrEmpty(s))
throw new ArgumentException("There is no first letter");
char[] a = s.ToCharArray();
a[0] = char.ToUpper(a[0]);
return new string(a);
}
