Is there any easy way to create a class that uses IFormatProvider that writes out a user-friendly file-size?
public static string GetFileSizeString(string filePath) { FileInfo info = new FileInfo(@"c:\windows\notepad.exe"); long size = info.Length; string sizeString = size.ToString(FileSizeFormatProvider); // This is where the class does its magic... }
It should result in strings formatted something like "2,5 MB", "3,9 GB", "670 bytes" and so on.
You can retrieve the length of the file with File#length(), which will return a value in bytes, so you need to divide this by 1024*1024 to get its value in mb.
FileInfo has a Length property. It returns the size of a file in bytes. We use FileInfo and the Length property to measure file sizes.
I use this one, I get it from the web
public class FileSizeFormatProvider : IFormatProvider, ICustomFormatter { public object GetFormat(Type formatType) { if (formatType == typeof(ICustomFormatter)) return this; return null; } private const string fileSizeFormat = "fs"; private const Decimal OneKiloByte = 1024M; private const Decimal OneMegaByte = OneKiloByte * 1024M; private const Decimal OneGigaByte = OneMegaByte * 1024M; public string Format(string format, object arg, IFormatProvider formatProvider) { if (format == null || !format.StartsWith(fileSizeFormat)) { return defaultFormat(format, arg, formatProvider); } if (arg is string) { return defaultFormat(format, arg, formatProvider); } Decimal size; try { size = Convert.ToDecimal(arg); } catch (InvalidCastException) { return defaultFormat(format, arg, formatProvider); } string suffix; if (size > OneGigaByte) { size /= OneGigaByte; suffix = "GB"; } else if (size > OneMegaByte) { size /= OneMegaByte; suffix = "MB"; } else if (size > OneKiloByte) { size /= OneKiloByte; suffix = "kB"; } else { suffix = " B"; } string precision = format.Substring(2); if (String.IsNullOrEmpty(precision)) precision = "2"; return String.Format("{0:N" + precision + "}{1}", size, suffix); } private static string defaultFormat(string format, object arg, IFormatProvider formatProvider) { IFormattable formattableArg = arg as IFormattable; if (formattableArg != null) { return formattableArg.ToString(format, formatProvider); } return arg.ToString(); } }
an example of use would be:
Console.WriteLine(String.Format(new FileSizeFormatProvider(), "File size: {0:fs}", 100)); Console.WriteLine(String.Format(new FileSizeFormatProvider(), "File size: {0:fs}", 10000));
Credits for http://flimflan.com/blog/FileSizeFormatProvider.aspx
There is a problem with ToString(), it's expecting a NumberFormatInfo type that implements IFormatProvider but the NumberFormatInfo class is sealed :(
If you're using C# 3.0 you can use an extension method to get the result you want:
public static class ExtensionMethods { public static string ToFileSize(this long l) { return String.Format(new FileSizeFormatProvider(), "{0:fs}", l); } }
You can use it like this.
long l = 100000000; Console.WriteLine(l.ToFileSize());
Hope this helps.
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