C#中String.Format的使用

喜欢ヅ旅行 2022-08-25 01:25 201阅读 0赞

String.Format的使用方法如下:  
string errorString = String.Format(”Error \{0\} occurred.”, nError);  
其中在花括號中的內容格式如下: **\{index\[,alignment\]\[:formatString\]\}**.  
參數說明:  
index表示的參數的序列值  
alignment表示對齊方式,省略或為正數,則向右靠齊.如果為負,則向左靠齊.不足的部分用空格填充.  
formatString表示格式化方式

1.Strings字符串格式化 
示例 輸出 
String.Format(”->\{1,10\}<-”, “Hello”); -> Hello<- 
String.Format(”->\{1,-10\}<-”, “Hello”); ->Hello <-

2.Numbers數值格式化  
\--1.基本的格式化字符

<table style="WIDTH: 631px; HEIGHT: 342px"> 
 <tbody> 
 <tr> 
 <td align="center">字符</td> 
 <td align="center">類型</td> 
 <td align="center">格式</td> 
 <td align="center"> Output (Passed Double 1.42) </td> 
 <td align="center"> Output (Passed Int -12400) </td> 
 </tr> 
 <tr> 
 <td align="center">c</td> 
 <td>Currency</td> 
 <td>{0:c}</td> 
 <td>＄1.42</td> 
 <td>-＄12,400</td> 
 </tr> 
 <tr> 
 <td align="center">d</td> 
 <td>Decimal (Whole number)</td> 
 <td>{0:d}</td> 
 <td>System. FormatException</td> 
 <td>-12400</td> 
 </tr> 
 <tr> 
 <td align="center">e</td> 
 <td>Scientific</td> 
 <td>{0:e}</td> 
 <td>1.420000e+000</td> 
 <td>-1.240000e+004</td> 
 </tr> 
 <tr> 
 <td align="center">f</td> 
 <td>Fixed point</td> 
 <td>{0:f}</td> 
 <td>1.42</td> 
 <td>-12400.00</td> 
 </tr> 
 <tr> 
 <td align="center">g</td> 
 <td>General</td> 
 <td>{0:g}</td> 
 <td>1.42</td> 
 <td>-12400</td> 
 </tr> 
 <tr> 
 <td align="center">n</td> 
 <td>Number with commas for thousands</td> 
 <td>{0:n}</td> 
 <td>1.42</td> 
 <td>-12,400</td> 
 </tr> 
 <tr> 
 <td align="center">r</td> 
 <td>Round trippable</td> 
 <td>{0:r}</td> 
 <td>1.42</td> 
 <td>System. FormatException</td> 
 </tr> 
 <tr> 
 <td align="center">x</td> 
 <td>Hexadecimal</td> 
 <td>{0:x4}</td> 
 <td>System. FormatException</td> 
 <td>cf90</td> 
 </tr> 
 </tbody> 
</table>

示例:

string.Format("\{0:C3\}", 2) //輸出 ＄2.000  
string.Format("\{0:D3\}", 2) //輸出 002  
string.Format("\{0:G\}", 2) //輸出 2  
string.Format("\{0:N\}", 250000) //輸出 250,000.00  
string.Format("\{0:X000\}", 12) //輸出 C

\--2.自定義數值格式

示例:

String.Format("\{0:0000\}",157) //輸出 0157  
String.Format("\{0:0000.0000\}",157.42) //輸出 0157.4200

String.Format("\{0:(\#\#\#) \#\#\#-\#\#\#\#\}", 8005551212) //輸出 (800) 555-1212

String.Format("\{0:0,0\}", 38560) //輸出 38,560

String.Format("\{0:0%\}", 0.283333) //輸出28%  
String.Format("\{0:0.00%\}",0.283333); // 輸出 28.33%

String.Format("\{0:$\#,\#\#0.00;($\#,\#\#0.00);Zero\}", 0) //輸出 Zero  
String.Format("\{0:$\#,\#\#0.00;($\#,\#\#0.00);Zero\}", 1243.50) //輸出 $1,243.50

3.Dates日期格式化  
\--1.基本的日期格式化字符

\--2.自定義日期格式

<table> 
 <tbody> 
 <tr> 
 <td align="center">字符</td> 
 <td align="center">類型</td> 
 <td align="center">示例</td> 
 <td align="center">輸出</td> 
 </tr> 
 <tr> 
 <td align="center">dd</td> 
 <td>Day</td> 
 <td align="center">{0:dd}</td> 
 <td>10</td> 
 </tr> 
 <tr> 
 <td align="center">ddd</td> 
 <td>Day name</td> 
 <td align="center">{0:ddd}</td> 
 <td>Tue</td> 
 </tr> 
 <tr> 
 <td align="center">dddd</td> 
 <td>Full day name</td> 
 <td align="center">{0:dddd}</td> 
 <td>Tuesday</td> 
 </tr> 
 <tr> 
 <td align="center">f, ff, …</td> 
 <td>Second fractions</td> 
 <td align="center">{0:fff}</td> 
 <td>932</td> 
 </tr> 
 <tr> 
 <td align="center">gg, …</td> 
 <td>Era</td> 
 <td align="center">{0:gg}</td> 
 <td>A.D.</td> 
 </tr> 
 <tr> 
 <td align="center">hh</td> 
 <td>2 digit hour</td> 
 <td align="center">{0:hh}</td> 
 <td>10</td> 
 </tr> 
 <tr> 
 <td align="center">HH</td> 
 <td>2 digit hour, 24hr format</td> 
 <td align="center">{0:HH}</td> 
 <td>22</td> 
 </tr> 
 <tr> 
 <td align="center">mm</td> 
 <td>Minute 00-59</td> 
 <td align="center">{0:mm}</td> 
 <td>38</td> 
 </tr> 
 <tr> 
 <td align="center">MM</td> 
 <td>Month 01-12</td> 
 <td align="center">{0:MM}</td> 
 <td>12</td> 
 </tr> 
 <tr> 
 <td align="center">MMM</td> 
 <td>Month abbreviation</td> 
 <td align="center">{0:MMM}</td> 
 <td>Dec</td> 
 </tr> 
 <tr> 
 <td align="center">MMMM</td> 
 <td>Full month name</td> 
 <td align="center">{0:MMMM}</td> 
 <td>December</td> 
 </tr> 
 <tr> 
 <td align="center">ss</td> 
 <td>Seconds 00-59</td> 
 <td align="center">{0:ss}</td> 
 <td>46</td> 
 </tr> 
 <tr> 
 <td align="center">tt</td> 
 <td>AM or PM</td> 
 <td align="center">{0:tt}</td> 
 <td>PM</td> 
 </tr> 
 <tr> 
 <td align="center">yy</td> 
 <td>Year, 2 digits</td> 
 <td align="center">{0:yy}</td> 
 <td>02</td> 
 </tr> 
 <tr> 
 <td align="center">yyyy</td> 
 <td>Year</td> 
 <td align="center">{0:yyyy}</td> 
 <td>2002</td> 
 </tr> 
 <tr> 
 <td align="center">zz</td> 
 <td>Timezone offset, 2 digits</td> 
 <td align="center">{0:zz}</td> 
 <td>-05</td> 
 </tr> 
 <tr> 
 <td align="center">zzz</td> 
 <td>Full timezone offset</td> 
 <td align="center">{0:zzz}</td> 
 <td>-05:00</td> 
 </tr> 
 <tr> 
 <td align="center">:</td> 
 <td>Separator</td> 
 <td align="center">{0:hh:mm:ss}</td> 
 <td>10:43:20</td> 
 </tr> 
 <tr> 
 <td align="center">/</td> 
 <td>Separator</td> 
 <td align="center">{0:dd/MM/yyyy}</td> 
 <td>10/12/2002</td> 
 </tr> 
 </tbody> 
</table>

4.Enumerations枚舉格式化

<table> 
 <tbody> 
 <tr> 
 <td align="center">字符</td> 
 <td align="center">類型</td> 
 </tr> 
 <tr> 
 <td align="center">g</td> 
 <td>Default (Flag names if available, otherwise decimal)</td> 
 </tr> 
 <tr> 
 <td align="center">f</td> 
 <td>Flags always</td> 
 </tr> 
 <tr> 
 <td align="center">d</td> 
 <td>Integer always</td> 
 </tr> 
 <tr> 
 <td align="center">x</td> 
 <td>Eight digit hex.</td> 
 </tr> 
 </tbody> 
</table>

本文參考資料:[http://blog.stevex.net/index.php/string-formatting-in-csharp/][http_blog.stevex.net_index.php_string-formatting-in-csharp]

[http_blog.stevex.net_index.php_string-formatting-in-csharp]: http://blog.stevex.net/index.php/string-formatting-in-csharp/