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

另一种皮肤的方法，没有任何类型的循环和负大小支持(对文件大小增量有意义):

public static class Format
{
    static string[] sizeSuffixes = {
        "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" };

    public static string ByteSize(long size)
    {
        Debug.Assert(sizeSuffixes.Length > 0);

        const string formatTemplate = "{0}{1:0.#} {2}";

        if (size == 0)
        {
            return string.Format(formatTemplate, null, 0, sizeSuffixes[0]);
        }

        var absSize = Math.Abs((double)size);
        var fpPower = Math.Log(absSize, 1000);
        var intPower = (int)fpPower;
        var iUnit = intPower >= sizeSuffixes.Length
            ? sizeSuffixes.Length - 1
            : intPower;
        var normSize = absSize / Math.Pow(1000, iUnit);

        return string.Format(
            formatTemplate,
            size < 0 ? "-" : null, normSize, sizeSuffixes[iUnit]);
    }
}

下面是测试套件:

[TestFixture] public class ByteSize
{
    [TestCase(0, Result="0 B")]
    [TestCase(1, Result = "1 B")]
    [TestCase(1000, Result = "1 KB")]
    [TestCase(1500000, Result = "1.5 MB")]
    [TestCase(-1000, Result = "-1 KB")]
    [TestCase(int.MaxValue, Result = "2.1 GB")]
    [TestCase(int.MinValue, Result = "-2.1 GB")]
    [TestCase(long.MaxValue, Result = "9.2 EB")]
    [TestCase(long.MinValue, Result = "-9.2 EB")]
    public string Format_byte_size(long size)
    {
        return Format.ByteSize(size);
    }
}

我喜欢使用以下方法(它支持高达tb，这在大多数情况下已经足够了，但它可以很容易地扩展):

private string GetSizeString(long length)
{
    long B = 0, KB = 1024, MB = KB * 1024, GB = MB * 1024, TB = GB * 1024;
    double size = length;
    string suffix = nameof(B);

    if (length >= TB) {
        size = Math.Round((double)length / TB, 2);
        suffix = nameof(TB);
    }
    else if (length >= GB) {
        size = Math.Round((double)length / GB, 2);
        suffix = nameof(GB);
    }
    else if (length >= MB) {
        size = Math.Round((double)length / MB, 2);
        suffix = nameof(MB);
    }
    else if (length >= KB) {
        size = Math.Round((double)length / KB, 2);
        suffix = nameof(KB);
    }

    return $"{size} {suffix}";
}

请记住，这是为c# 6.0(2015)编写的，因此对于较早的版本可能需要进行一些编辑。

下面是一个Log10的方法:

using System;

class Program {
   static string NumberFormat(double n) {
      var n2 = (int)Math.Log10(n) / 3;
      var n3 = n / Math.Pow(1e3, n2);
      return String.Format("{0:f3}", n3) + new[]{"", " k", " M", " G"}[n2];
   }

   static void Main() {
      var s = NumberFormat(9012345678);
      Console.WriteLine(s == "9.012 G");
   }
}

https://learn.microsoft.com/dotnet/api/system.math.log10

请求函数的测试和显著优化版本发布在这里:

c#人类可读文件大小-优化的函数

源代码:

// Returns the human-readable file size for an arbitrary, 64-bit file size 
// The default format is "0.### XB", e.g. "4.2 KB" or "1.434 GB"
public string GetBytesReadable(long i)
{
    // Get absolute value
    long absolute_i = (i < 0 ? -i : i);
    // Determine the suffix and readable value
    string suffix;
    double readable;
    if (absolute_i >= 0x1000000000000000) // Exabyte
    {
        suffix = "EB";
        readable = (i >> 50);
    }
    else if (absolute_i >= 0x4000000000000) // Petabyte
    {
        suffix = "PB";
        readable = (i >> 40);
    }
    else if (absolute_i >= 0x10000000000) // Terabyte
    {
        suffix = "TB";
        readable = (i >> 30);
    }
    else if (absolute_i >= 0x40000000) // Gigabyte
    {
        suffix = "GB";
        readable = (i >> 20);
    }
    else if (absolute_i >= 0x100000) // Megabyte
    {
        suffix = "MB";
        readable = (i >> 10);
    }
    else if (absolute_i >= 0x400) // Kilobyte
    {
        suffix = "KB";
        readable = i;
    }
    else
    {
        return i.ToString("0 B"); // Byte
    }
    // Divide by 1024 to get fractional value
    readable = (readable / 1024);
    // Return formatted number with suffix
    return readable.ToString("0.### ") + suffix;
}

我的观点是:

千字节的前缀是kB(小写K) 由于这些函数用于表示目的，因此应该提供区域性，例如:CurrentCulture,“{0时。##}{1}"，文件大小，单位); 根据上下文，千字节可以是1000字节或1024字节。MB、GB等也是如此。