我如何获得一个人类可读的文件大小字节缩写使用。net ?
例子: 输入7,326,629,显示6.98 MB
我如何获得一个人类可读的文件大小字节缩写使用。net ?
例子: 输入7,326,629,显示6.98 MB
当前回答
为了获得人类可读的字符串,就像用户在Windows环境中习惯的那样,你应该使用StrFormatByteSize():
using System.Runtime.InteropServices;
...
private long mFileSize;
[DllImport("Shlwapi.dll", CharSet = CharSet.Auto)]
public static extern int StrFormatByteSize(
long fileSize,
[MarshalAs(UnmanagedType.LPTStr)] StringBuilder buffer,
int bufferSize);
public string HumanReadableFileSize
{
get
{
var sb = new StringBuilder(20);
StrFormatByteSize(mFileSize, sb, 20);
return sb.ToString();
}
}
我在这里找到了这个: http://csharphelper.com/blog/2014/07/format-file-sizes-in-kb-mb-gb-and-so-forth-in-c/
其他回答
又多了一种方法,不管怎样。我喜欢上面提到的@humbads优化解决方案,所以复制了原理,但我实现了一点不同。
我认为它是否应该是一个扩展方法是有争议的(因为不是所有的long都必须是字节大小),但我喜欢它们,当我下次需要它时,我可以在某个地方找到它!
关于单位,我想我从来没有说过“Kibibyte”或“Mebibyte”,虽然我对这种强制而非进化的标准持怀疑态度,但我认为从长远来看,这将避免混淆。
public static class LongExtensions
{
private static readonly long[] numberOfBytesInUnit;
private static readonly Func<long, string>[] bytesToUnitConverters;
static LongExtensions()
{
numberOfBytesInUnit = new long[6]
{
1L << 10, // Bytes in a Kibibyte
1L << 20, // Bytes in a Mebibyte
1L << 30, // Bytes in a Gibibyte
1L << 40, // Bytes in a Tebibyte
1L << 50, // Bytes in a Pebibyte
1L << 60 // Bytes in a Exbibyte
};
// Shift the long (integer) down to 1024 times its number of units, convert to a double (real number),
// then divide to get the final number of units (units will be in the range 1 to 1023.999)
Func<long, int, string> FormatAsProportionOfUnit = (bytes, shift) => (((double)(bytes >> shift)) / 1024).ToString("0.###");
bytesToUnitConverters = new Func<long,string>[7]
{
bytes => bytes.ToString() + " B",
bytes => FormatAsProportionOfUnit(bytes, 0) + " KiB",
bytes => FormatAsProportionOfUnit(bytes, 10) + " MiB",
bytes => FormatAsProportionOfUnit(bytes, 20) + " GiB",
bytes => FormatAsProportionOfUnit(bytes, 30) + " TiB",
bytes => FormatAsProportionOfUnit(bytes, 40) + " PiB",
bytes => FormatAsProportionOfUnit(bytes, 50) + " EiB",
};
}
public static string ToReadableByteSizeString(this long bytes)
{
if (bytes < 0)
return "-" + Math.Abs(bytes).ToReadableByteSizeString();
int counter = 0;
while (counter < numberOfBytesInUnit.Length)
{
if (bytes < numberOfBytesInUnit[counter])
return bytesToUnitConverters[counter](bytes);
counter++;
}
return bytesToUnitConverters[counter](bytes);
}
}
如果你试图匹配Windows资源管理器的详细信息视图中显示的大小,这是你想要的代码:
[DllImport("shlwapi.dll", CharSet = CharSet.Unicode)]
private static extern long StrFormatKBSize(
long qdw,
[MarshalAs(UnmanagedType.LPTStr)] StringBuilder pszBuf,
int cchBuf);
public static string BytesToString(long byteCount)
{
var sb = new StringBuilder(32);
StrFormatKBSize(byteCount, sb, sb.Capacity);
return sb.ToString();
}
这不仅会与资源管理器完全匹配,而且还会为您提供翻译后的字符串,并匹配Windows版本的差异(例如在Win10中,K = 1000 vs.之前的版本K = 1024)。
下面是@ deepe1的BigInteger版本的答案,它绕过了long的大小限制(因此支持yottabyte和理论上的任何后面的限制):
public static string ToBytesString(this BigInteger byteCount, string format = "N3")
{
string[] suf = { "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "YiB" };
if (byteCount.IsZero)
{
return $"{0.0.ToString(format)} {suf[0]}";
}
var abs = BigInteger.Abs(byteCount);
var place = Convert.ToInt32(Math.Floor(BigInteger.Log(abs, 1024)));
var pow = Math.Pow(1024, place);
// since we need to do this with integer math, get the quotient and remainder
var quotient = BigInteger.DivRem(abs, new BigInteger(pow), out var remainder);
// convert the remainder to a ratio and add both back together as doubles
var num = byteCount.Sign * (Math.Floor((double)quotient) + ((double)remainder / pow));
return $"{num.ToString(format)} {suf[place]}";
}
为了获得人类可读的字符串,就像用户在Windows环境中习惯的那样,你应该使用StrFormatByteSize():
using System.Runtime.InteropServices;
...
private long mFileSize;
[DllImport("Shlwapi.dll", CharSet = CharSet.Auto)]
public static extern int StrFormatByteSize(
long fileSize,
[MarshalAs(UnmanagedType.LPTStr)] StringBuilder buffer,
int bufferSize);
public string HumanReadableFileSize
{
get
{
var sb = new StringBuilder(20);
StrFormatByteSize(mFileSize, sb, 20);
return sb.ToString();
}
}
我在这里找到了这个: http://csharphelper.com/blog/2014/07/format-file-sizes-in-kb-mb-gb-and-so-forth-in-c/
这里没有什么东西完全符合我的需要,我根据这个线程制作了我自己的,所以这里是我的长扩展,允许您根据标准选择格式要求。
绝对不是最快的,但很灵活。支持EB/EiB。
// <summary>
/// <paramref name="byteCount"/> The original size in bytes ( 8 bits )
/// <paramref name="notationFormat"/> is supported in the following ways:
/// [ 'B' / 'b' : Binary : Kilobyte (KB) is 1024 bytes, Megabyte (MB) is 1048576 bytes, etc ]
/// [ 'I' / 'i' : IEC: Kibibyte (KiB) is 1024 bytes, Mebibyte (MiB) is 1048576 bytes, etc ]
/// [ 'D' / 'd' : Decimal : Kilobyte (KB) is 1000 bytes, Megabyte (MB) is 1000000 bytes, etc ]
/// </summary>
public static string ToDataSizeString( this long byteCount, char notationFormat = 'b' )
{
char[] supportedFormatChars = { 'b', 'i', 'd' };
var lowerCaseNotationFormat = char.ToLowerInvariant( notationFormat );
// Stop shooting holes in my ship!
if ( !supportedFormatChars.Contains( lowerCaseNotationFormat ) )
{
throw new ArgumentException( $"notationFormat argument '{notationFormat}' not supported" );
}
long ebLimit = 1152921504606846976;
long pbLimit = 1125899906842624;
long tbLimit = 1099511627776;
long gbLimit = 1073741824;
long mbLimit = 1048576;
long kbLimit = 1024;
var ebSuffix = "EB";
var pbSuffix = "PB";
var tbSuffix = "TB";
var gbSuffix = "GB";
var mbSuffix = "MB";
var kbSuffix = "KB";
var bSuffix = " B";
switch ( lowerCaseNotationFormat )
{
case 'b':
// Sweet as
break;
case 'i':
// Limits stay the same, suffixes need changed
ebSuffix = "EiB";
pbSuffix = "PiB";
tbSuffix = "TiB";
gbSuffix = "GiB";
mbSuffix = "MiB";
kbSuffix = "KiB";
bSuffix = " B";
break;
case 'd':
// Suffixes stay the same, limits need changed
ebLimit = 1000000000000000000;
pbLimit = 1000000000000000;
tbLimit = 1000000000000;
gbLimit = 1000000000;
mbLimit = 1000000;
kbLimit = 1000;
break;
default:
// Should have already Excepted, but hey whatever
throw new ArgumentException( $"notationFormat argument '{notationFormat}' not supported" );
}
string fileSizeText;
// Exa/Exbi sized
if ( byteCount >= ebLimit )
{
fileSizeText = $"{( (double)byteCount / ebLimit ):N1} {ebSuffix}";
}
// Peta/Pebi sized
else if ( byteCount >= pbLimit )
{
fileSizeText = $"{( (double)byteCount / pbLimit ):N1} {pbSuffix}";
}
// Tera/Tebi sized
else if ( byteCount >= tbLimit )
{
fileSizeText = $"{( (double)byteCount / tbLimit ):N1} {tbSuffix}";
}
// Giga/Gibi sized
else if ( byteCount >= gbLimit )
{
fileSizeText = $"{( (double)byteCount / gbLimit ):N1} {gbSuffix}";
}
// Mega/Mibi sized
else if ( byteCount >= mbLimit )
{
fileSizeText = $"{( (double)byteCount / mbLimit ):N1} {mbSuffix}";
}
// Kilo/Kibi sized
else if ( byteCount >= kbLimit )
{
fileSizeText = $"{( (double)byteCount / kbLimit ):N1} {kbSuffix}";
}
// Byte sized
else
{
fileSizeText = $"{byteCount} {bSuffix}";
}
return fileSizeText;
}