Title: Formatting a File Size in Bytes for Display - Convert Bytes to String using Delphi
When working with files from Delphi you might want to display the size of a file to the user in a Explorer-like format where the file size is not displayed in bytes - but the display depends on the size of the actual file.
To most users "45678123 b" is confusing - where "43.56 MB" is much more user friendly.
Format Byte Size to String
A custom Delphi function, FormatByteSize, converts a byte value into a string that represents the number expressed as a size value in bytes, kilobytes, megabytes, or gigabytes, depending on the size.
//Format file byte size
function FormatByteSize(const bytes: Longint): string;
const
B = 1; //byte
KB = 1024 * B; //kilobyte
MB = 1024 * KB; //megabyte
GB = 1024 * MB; //gigabyte
begin
if bytes GB then
result := FormatFloat('#.## GB', bytes / GB)
else
if bytes MB then
result := FormatFloat('#.## MB', bytes / MB)
else
if bytes KB then
result := FormatFloat('#.## KB', bytes / KB)
else
result := FormatFloat('#.## bytes', bytes) ;
end;