怎么判断文件的大小?

Question

假设在我的电脑里有一张图片,我要知道它有多大?不用对话框如何实现?procedure TForm1.Button1Click(Sender: TObject);
 var
 f:file of integer;
 s:integer;
begin
assignfile(f,'我的照片.jpg');
reset(f);
s:=filesize(f);
showmessage(inttostr(s));我试了半天未能成功？难道非要用对话框来查找文件，才能得到文件的大小吗？

Answer 1

大小已经在S里了，直接可以拿来用啊，你想怎么样就怎么样啊
不用showmessage可以用另外方式啊

Answer 2

procedure TForm1.Button1Click(Sender: TObject);
var
 f:file of Byte;
begin
assignfile(f,'c:\2.jpg');
reset(f);
ShowMessage('File size now = '+IntToStr(FileSize(f)));
end;

Answer 3

var
    iFileHandle: Integer;
    iFileLength: Integer;
begin
    if OpenDialog1.Execute then
    begin
        iFileHandle := FileOpen(OpenDialog1.FileName, fmOpenRead);
        iFileLength := FileSeek(iFileHandle, 0, 2);
    end;
end;

Answer 4

樓主的也能得出結果吧。只是得出的大小的單位可能是‘32bit’，而不是Byte(8bit)

Answer 5

假设这个文件是网络链接，那怎么得到它的大小呢？
如：
var
 f:file of integer;
 s:integer;
begin
assignfile(f,'http://bbs.togame.net/attachment/Mon_0803/5_92040_ec8ef579ded1719.gif');
reset(f);
s:=filesize(f);
showmessage(inttostr(s));
end;

Answer 6

var
  theFile: TFileStream;
begin
  if FileExists('我的照片.jpg') then
  begin
    theFile:= TFileStream.Create('我的照片.jpg',fmOpenRead);
    showmessage(FloattoStr(Trunc(SelectedFile.Size / 1024 * 100) / 100) +' KB');
    theFile.free;
  end;
end;

Answer 7

to 8procedure TForm1.Button6Click(Sender: TObject);
var
h:TIdhttp;
f:file of byte;
MyStream:TMemoryStream;
begin
MyStream:=TMemoryStream.Create;
h:=Tidhttp.Create(nil);
try
h.get('http://bbs.togame.net/attachment/Mon_0803/5_92040_ec8ef579ded1719.gif',MyStream);
except
showmessage('网络出错!');
MyStream.Free;
exit;
end;
MyStream.SaveToFile('c:\1.gif');
//sleep(100);
assignfile(f,'c:\1.gif');
reset(f);
ShowMessage('gif size now = '+FloatToStr((Trunc(FileSize(f)/1024 * 10))/10)+'kb');
MyStream.Free;
end;

Answer 8

procedure TForm1.Button1Click(Sender: TObject);
var
  iFileSize: Integer;
begin
  IdHTTP1.Head('http://bbs.togame.net/attachment/Mon_0803/5_92040_ec8ef579ded1719.gif');
  iFileSize:= IdHTTP1.Response.ContentLength;
  ShowMessage('gif size now = '+FloatToStr((Trunc(iFileSize/1024 * 10))/10)+'kb');
end;这个应该是你想要！

Answer 9

function TWebWorld.HttpQueryInfo(hRequest: HINTERNET; var dwFileSize: DWORD): LongBool;
var
    dwBufferSize: DWORD;
    dwIndex: DWORD;    InfoBuffer: array[1..32] of Byte;    Info: string;
    bQuery: LongBool;
begin
    dwBufferSize := 32;
    dwIndex := 0;    bQuery := WiniNet.HttpQueryInfo(hRequest, HTTP_QUERY_CONTENT_LENGTH, @InfoBuffer, dwBufferSize, dwIndex);    if bQuery then
    begin
        Info := pChar(@InfoBuffer);
        dwFileSize := SysUtils.StrToInt(Info);
    end;    result := bQuery;
end;

Answer 10

var
    hConnect: HINTERNET;
    hRequest: HINTERNET;    dwFileSize: DWORD;
    dwError: DWORD;
    dwPosition: DWORD;
    dwBytesRead: DWORD;    bTerminate: LongBool;
    bSucceed: LongBool;    lpBuffer: Pointer;    f: file;
begin
    hConnect := InternetConnect;//创建连接
    hRequest := HttpOpenRequest(hConnect);    while not HttpSendRequest(hRequest) do//发送请求
    begin
        dwError := GetLastError();
        if (dwError = ERROR_INTERNET_CLIENT_AUTH_CERT_NEEDED) and
            (InternetErrorDlg(hConnect) = ERROR_SUCCESS) then
            Continue;        InternetCloseHandle(hRequest);
        InternetCloseHandle(hConnect);
        exit;
    end;    if not HttpQueryInfo(hRequest, dwFileSize) then exit;//取得服务器文件长度
    try
        AssignFile(f, FFielName);
        Rewrite(f, 1);
        dwPosition := 0; //启始位置        if Assigned(FOnOpenWork) then FOnOpenWork(self, dwFileSize);        bSucceed := false;
        bTerminate := false;        while true do
        begin
            if Assigned(FOnOverWork) then FOnOverWork(self, dwPosition, bTerminate);//OnOverWork事件，用来显示文件下载进度
            if bTerminate then Break;
            if not InternetReadFile(hRequest, dwPosition, dwBytesRead, lpBuffer) then Break;
            if dwBytesRead = 0 then
            begin
                bSucceed := true;
                Break;
            end;
            BlockWrite(f, lpBuffer^, dwBytesRead);//写块lpBuffer
        end;
        if Assigned(FOnCloseWork) then FOnCloseWork(self, bSucceed);//OnCloseWork下载工作关闭时间
        CloseFile(f);    finally
        InternetCloseHandle(hRequest);
        InternetCloseHandle(hConnect);
    end;
end;以上是部分文件下载的部分代码