[英]Get search path by handle when using FindNextFile?
I use FindFirstFile()
and FindNextFile()
to list files of a directory.我使用
FindFirstFile()
和FindNextFile()
来列出目录的文件。 When I call FindFirstFile()
, I have to give a search path to it.当我调用
FindFirstFile()
时,我必须为其提供搜索路径。 It returns a handle that can be used by FindNextFile()
.它返回一个可供
FindNextFile()
使用的句柄。 Is there a WinAPI function that can get the previously given path by the handle?有没有 WinAPI function 可以通过句柄得到之前给定的路径?
Just store that information like you store the search handle already: in a variable.只需存储该信息,就像您已经存储搜索句柄一样:在一个变量中。 Then create your own wrapper functions for both
FindFirstFileA()
and FindNextFileA()
:然后为
FindFirstFileA()
和FindNextFileA()
创建自己的包装函数:
type
// What you want to give back per file system object
TMyFindInfo= record // Whatever you want to do here on your own
wfd: Windows.WIN32_FIND_DATAA; // Just provide this as-is because it already everything
end;
// Not only storing the handle, but also other details
TMyFindHandle= record
h: THandle; // Search resource
sFilter: String; // Original query
iMatches, // How often did the search yield a file system object?
iError: Cardinal; // Which error has occured? 0=ERROR_SUCCESS.
end;
function MyFindFile1st
( const sFilter: String
; out vInfo: TMyFindInfo
): TMyFindHandle;
begin
result.sFilter:= sFilter;
result.h:= Windows.FindFirstFileA( PChar(sFilter), vInfo.wfd );
if result.h= INVALID_HANDLE_VALUE then begin
result.iError:= Windows.GetLastError();
case result.iError of
ERROR_FILE_NOT_FOUND: ; // The only error we don't need to display
else // Most likely ERROR_PATH_NOT_FOUND
Windows.MessageBoxA
( Form1.Handle
, PChar('Error initializing search "'+ result.sFilter
+ '": 0x'+ IntToHex( result.iError, 8 )) // Get text message elsewhere
, PChar('Error')
, MB_ICONSTOP
);
end;
result.iMatches:= 0;
ZeroMemory( @vInfo, SizeOf( vInfo ) ); // Nothing to see here
end else begin
result.iError:= ERROR_SUCCESS;
result.iMatches:= 1;
end;
end;
function MyFindFile2nd
( var vHandle: TMyFindHandle
; out vInfo: TMyFindInfo
): Boolean;
begin
result:= Windows.FindNextFileA( vHandle.h, vInfo.wfd );
if not result then begin
vHandle.iError:= Windows.GetLastError();
case vHandle.iError of
ERROR_SUCCESS, // The only errors we don't need to display
ERROR_NO_MORE_FILES: ;
else
Windows.MessageBoxA
( Form1.Handle
, PChar('Error during search "'+ vHandle.sFilter // Original filter from 1st call
+ '" after '+ IntToStr( vHandle.iMatches )+ ' elements occured: 0x'
+ IntToHex( vHandle.iError, 8 ))
, PChar('Error')
, MB_ICONSTOP
);
end;
Windows.ZeroMemory( @vInfo, SizeOf( vInfo ) ); // Nothing to see here
if not Windows.FindClose( vHandle.h ) then begin // Release resource
vHandle.iError:= Windows.GetLastError();
case vHandle.iError of
ERROR_SUCCESS: ;
else // Yes, this can fail, too
Windows.MessageBoxA
( Form1.Handle
, PChar('Error finalizing search "'+ vHandle.sFilter // Original filter from 1st call
+ '" after '+ IntToStr( vHandle.iMatches )+ ' elements occured: 0x'
+ IntToHex( vHandle.iError, 8 ))
, PChar('Error')
, MB_ICONSTOP
);
end;
end;
end else Inc( vHandle.iMatches ); // One more match
end;
// Now the example on how to use it
procedure TForm1.Button1Click(Sender: TObject);
var
vHandle: TMyFindHandle;
vInfo: TMyFindInfo;
begin
vHandle:= MyFindFile1st( 'C:\Windows\*.exe', vInfo );
while vHandle.iError= ERROR_SUCCESS do begin
Memo1.Lines.Add( vInfo.wfd.cFileName );
MyFindFile2nd( vHandle, vInfo ); // Don't even need the Boolean result here
end;
Memo1.Lines.Add( '= '+ IntToStr( vHandle.iMatches )+ ' FS objects' ); // Not only files
end;
At no time there is a need to re-request a detail by handle, because you can keep that detail right with the handle that you need to take care of anyway.任何时候都不需要通过 handle 重新请求详细信息,因为您可以通过无论如何需要处理的 handle 保持该详细信息正确。 Just put both together into a record and pass that to your own functions.
只需将两者放在一起记录并将其传递给您自己的函数即可。
My code is for demonstration purposes (although I think it's a rather trivial overall case).我的代码用于演示目的(尽管我认为这是一个相当微不足道的整体案例)。 I discourage from displaying dialog windows right in those functions, but instead react upon what
vHandle.iError
contains where I called those functions.我不鼓励在这些函数中直接显示对话框 windows,而是对我调用这些函数的地方包含的
vHandle.iError
做出反应。
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