C# Signature:
[DllImport("kernel32.dll")]
static extern uint GetCompressedFileSize(string lpFileName,
out uint lpFileSizeHigh);
VB .NET Signature:
Private Declare Function GetCompressedFileSize Lib "kernel32" Alias "GetCompressedFileSizeA" (ByVal lpFileName As String, ByVal lpFileSizeHigh As IntPtr) As UInt32
Legacy VB Signature:
Private Declare Function GetCompressedFileSize Lib "kernel32" Alias "GetCompressedFileSizeA" (ByVal lpFileName As String, lpFileSizeHigh As Long) As Long
User-Defined Types:
None.
Notes:
The C# code below correctly obtains the compressed file size if >4 GB. The sample VB code does not appear to do so properly.
Tips & Tricks:
Please add some!
Sample Code C#:
[DllImport("kernel32.dll", SetLastError=true, EntryPoint="GetCompressedFileSize")]
static extern uint GetCompressedFileSizeAPI(string lpFileName, out uint lpFileSizeHigh);
public ulong GetCompressedFileSize(string filename)
{
uint high;
uint low;
low = GetCompressedFileSizeAPI(filename, out high);
int error = Marshal.GetLastWin32Error();
if (high == 0 && low == 0xFFFFFFFF && error != 0)
throw new Win32Exception(error);
else
return ((ulong)high << 32) + low;
}
Sample Code VB .NET:
Imports System.IO
·
·
·
Public Function CompressedFileSize(ByVal path As String) As Long
If File.Exist(path) Then
Try
øReturn Convert.ToInt64(GetCompressedFileSize(path, IntPtr.Zero))
' To handle 4Gb+ a bit more complex:
Dim ptr As IntPtr = Marshal.AllocHGlobal(4)
Marshal.WriteInt32(ptr, FileSizeHigh)
Dim filelength as Long = Convert.ToInt64(GetCompressedFileSize(path, ptr))
filesizehigh = Marshal.ReadInt32(ptr)
filelength += CLng(filesizehigh) << 32
Marshal.FreeHGlobal(ptr)
Return filelength
Catch ex As Exception
Throw New IOException("The compressed size of the specified file could not be determined.")
End Try
End If
End Function
Sample code legacy VB:
Private Sub GetFileSize(ByVal strPath As String)
MsgBox "The size of " + strPath " is " + CStr(GetCompressedFileSize(strPath, ByVal 0&)) + " bytes "
End Sub
Alternative Managed API:
The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides an ExtendedFileInfo class that contains utility methods for file information.
