[C#.net] Two ways to determine whether a file is occupied

The first method: API

Using System.IO;

Using System.Runtime.InteropServices;

[DllImport ("kernel32.dll")]

public static extern IntPtr _lopen (string lppathname,int ireadwrite);

[DllImport ("kernel32.dll")]

public static extern bool CloseHandle (IntPtr hobject);

public const int of_readwrite=2;

public const int of_share_deny_none=0x40;

Public readonly IntPtr hfile_error=new IntPtr (-1);

private void Button1_Click (Object Sender,eventargs e)

{

string [email protected] "c:\temp\temp.bmp";

if (! File.exists (Vfilename))

{

MessageBox.Show ("The file does not exist!");

Return

}

IntPtr Vhandle=_lopen (vfilename,of_readwrite| Of_share_deny_none);

if (vhandle==hfile_error)

{

MessageBox.Show ("File is occupied!");

Return

}

CloseHandle (Vhandle);

MessageBox.Show ("Not occupied! ");

The second method: FileStream

public static bool Isfileinuse (string fileName)

BOOL Inuse=true;

FileStream Fs=null;

Try

{

Fs=new FileStream (Filename,filemode.open,fileaccess.read,fileshare.none);

Inuse=false;

}

Catch

{

}

Finally

{

if (fs!=null)

Fs. Close ();

}

return inUse;

}

Part of the Project Code (vb.net)

Sub Prepare ()

If file.exits (LOGRW) then File.delete (LOGRW)

Dim Bflag as Boolean=false

Try

Do

Shell ("cmd.exe/c rw.exe/command=limita.rw/logfile-limita.log", appwinstyle.hide,true,5000)

Threading.Thread.Sleep (1000)

while (Isfileinuse ("LimitA.log"))

Threading.Thread.Sleep (2000)

End while

If file.exists (LOGRW) Then

Dim all as String=my.computer.filesystem.readalltext (LOGRW)

If all.contains ("Read EC Byte ox01=0x80") Then

Bflag=true

End If

End If

Loop Until Bflag

Using SR as New StreamReader (LOGRW)

Do Until Sr. Endofstream

Dim s as STRING=SR. ReadLine

If s.contains ("Set environment RwLOCAL3") then

' Set Environment rwlocal3=4608 (DEC)

Limita=cdbl (S.split (New String () {"=", "("},stringsplitoptions.removeemptyentries (1))

Console.WriteLine ("Limit Current:" &limita)

logstr=logstr&vbcrlf& "Limit Current:" &limita

Exit do

End If

Loop

End Using

Catch ex as Exception

Console.writelien (ex. Message &err.description)

Environment.exit (1)

End Try

End Sub

Function Isfileinuse (ByVal fileName as String)

Dim InUse as Boolean=true

Dim FS as Filestream=nothing

Try

Fs=new FileStream (Filename,filemoe.open,fileaccess.read,fileshare.none)

Inuse=false

Catch ex as Exception

Finally

If (fs IsNot Nothing) Then

Fs. Close ()

End If

End Try

Return InUse

End Function

[C#.net] Two ways to determine whether a file is occupied