判断文件是否使用中 Checking If File Is In Use

 

Checking If File Is In Use

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IsFileInUse will return true if the file is locked for exclusive access. It would fail if the file doesn't exist at all.

~~~~~~~~~~~~~~~~~~~~~~~~~
function IsFileInUse(fName : string) : boolean;
var
    HFileRes : HFILE;
begin
    Result := false;
    if not FileExists(fName) then exit;
    HFileRes :=
      CreateFile(pchar(fName),
                 GENERIC_READ or GENERIC_WRITE,
                 0, nil, OPEN_EXISTING,
                 FILE_ATTRIBUTE_NORMAL,
                 0) ;
    Result := (HFileRes = INVALID_HANDLE_VALUE) ;
    if not Result then
    CloseHandle
~~~~~~~~~~~~~~~~~~~~~~~~~

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uses wininet

 

if not InternetCheckConnection(PChar(CUrl), 1, 0) then
  Begin
    ShowMessage('网路不通!');
    Exit;
  End;