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
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);
}
}
其他回答
int size = new FileInfo( filePath ).Length / 1024;
string humanKBSize = string.Format( "{0} KB", size );
string humanMBSize = string.Format( "{0} MB", size / 1024 );
string humanGBSize = string.Format( "{0} GB", size / 1024 / 1024 );
我猜你要找的是“1.4 MB”而不是“1468006字节”?
我不认为在。net中有内置的方法来做到这一点。你只需要找出哪个单元是合适的,然后格式化它。
编辑:这里有一些示例代码来做到这一点:
http://www.codeproject.com/KB/cpp/formatsize.aspx
比如@NET3的解决方案。使用shift而不是除法来测试字节的范围,因为除法占用更多的CPU成本。
private static readonly string[] UNITS = new string[] { "B", "KB", "MB", "GB", "TB", "PB", "EB" };
public static string FormatSize(ulong bytes)
{
int c = 0;
for (c = 0; c < UNITS.Length; c++)
{
ulong m = (ulong)1 << ((c + 1) * 10);
if (bytes < m)
break;
}
double n = bytes / (double)((ulong)1 << (c * 10));
return string.Format("{0:0.##} {1}", n, UNITS[c]);
}
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)。
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/