Question

我在做什么：

用户点击一个按钮，FileUpload组件（对话框）会启动，他可以从他的PC浏览并加载文件。
当他点击“确定”时，文件会以特定的方式保存到磁盘中位置。
在保存之前，我正在使用包含的字符串重命名（或者更确切地说，使用特定名称保存）他的文件我之前从某些数据库字段中提取的数据。

因此，无论文件在用户加载时的名称如何，它都会以Firstname和LastName保存到磁盘中，这是我从一些字符串变量中获得的。

UniMainModule.foldername =包含保存文件的文件夹的路径。

UniMainModule.FirstName =包含用户的FirstName

UniMainModule.LastName =包含用户的姓氏

因此，文件将FirstName_LastName.pdf保存在foldername字符串提供的位置的磁盘上。

这是我正在使用的代码：

procedure TsomeForm.UniFileUpload1Completed(Sender: TObject; AStream: TFileStream);
var
  DestName : string;
  DestFolder : string;
begin
   DestFolder:=UniServerModule.StartPath+'files\'+UniMainModule.foldername+'\';
   DestName:=DestFolder+UniMainModule.FirstName+'_'+UniMainModule.LastName+'.pdf';
   CopyFile(PChar(AStream.FileName), PChar(DestName), False);
   ModalResult:= mrOk;
end;

根据我的理解，在CopyFile上阅读msdn后，通过False意味着它应该并且将覆盖现有文件。

如果该文件在该位置尚未显示该名称，则可以保存。

但是如果用户决定再次使用fileupload并上传新文件，则新文件将覆盖前一个文件。因为他们被保存为同名。

如果文件已经存在（该位置中存在具有该确切名称的文件），那么如何确保它不会被覆盖，但我不知道，在名称中被赋予了（1）什么东西，保留两个文件？

Answer 1

在循环中调用CopyFile()，将其bFailIfExists参数设置为TRUE，以便在CopyFile()失败且ERROR_FILE_EXISTS错误时重新使用新文件名代码。

例如：

procedure TsomeForm.UniFileUpload1Completed(Sender: TObject; AStream: TFileStream);
var
  DestName : string;
  DestFolder : string;
  n : integer;
begin
  DestFolder := UniServerModule.StartPath + 'files\' + UniMainModule.foldername + '\';
  DestName := UniMainModule.FirstName + '_' + UniMainModule.LastName + '.pdf';
  n := 0;

  while not CopyFile(PChar(AStream.FileName), PChar(DestFolder + DestName), True) do
  begin
    if GetLastError() <> ERROR_FILE_EXISTS then
    begin
      // error handling...
      Break;
    end;
    Inc(n);
    DestName := UniMainModule.FirstName + '_' + UniMainModule.LastName + ' (' + IntToStr(n) + ').pdf';
  end;

  ModalResult := mrOk;
end;

但是，您应该让操作系统为您完成工作，而不是手动处理。特别是因为操作系统有自己的方式重命名复制的文件，并且该命名方案可以从一个操作系统版本更改（并且有）。

而不是使用CopyFile()，而是使用SHFileOperation()代替FOF_RENAMEONCOLLISION标志：

如果目标名称中已存在目标名称的文件，则在移动，复制或重命名操作中为新名称操作文件。

例如：

uses
  ..., Winapi.ShellAPI;

procedure TsomeForm.UniFileUpload1Completed(Sender: TObject; AStream: TFileStream);
var
  DestName : string;
  DestFolder : string;
  fo : TSHFileOpStruct;
begin
  DestFolder := UniServerModule.StartPath + 'files\' + UniMainModule.foldername + '\';
  DestName := DestFolder + UniMainModule.FirstName + '_' + UniMainModule.LastName + '.pdf';

  ZeroMemory(@fo, SizeOf(fo));
  fo.Wnd := Handle;
  fo.wFunc := FO_COPY;
  fo.pFrom := PChar(AStream.FileName+#0);
  fo.pTo := PChar(DestName+#0);
  fo.fFlags := FOF_SILENT or FOF_NOCONFIRMATION or FOF_NOERRORUI or FOF_NOCONFIRMMKDIR or FOF_RENAMEONCOLLISION;

  if SHFileOperation(fo) <> 0 then
  begin
    // error handling...
  end
  else if fo.fAnyOperationsAborted then
  begin
    // abort handling ...
  end;

  ModalResult := mrOk;
end;

如果你需要知道操作系统为重命名的文件名选择了什么，那么还有一个FOF_WANTMAPPINGHANDLE标志：

如果指定了FOF_RENAMEONCOLLISION并且重命名了任何文件，请将包含旧名称和新名称的名称映射对象分配给hNameMappings成员。当不再需要时，必须使用SHFreeNameMappings释放此对象。

例如：

uses
  ..., Winapi.ShellAPI;

type
  PHandleToMappings = ^THandleToMappings;
  THandleToMappings = record
    uNumberOfMappings: UINT;                          // Number of mappings in the array.
    lpSHNameMappings: array[0..0] of PSHNAMEMAPPINGW; // array of pointers to mappings.
  end;

procedure TsomeForm.UniFileUpload1Completed(Sender: TObject; AStream: TFileStream);
var
  DestName : string;
  DestFolder : string;
  fo : TSHFileOpStruct;
  pMappings : PHandleToMappings;
  pMapping : PSHNAMEMAPPINGW;
begin
  DestFolder := UniServerModule.StartPath + 'files\' + UniMainModule.foldername + '\';
  DestName := DestFolder + UniMainModule.FirstName + '_' + UniMainModule.LastName + '.pdf';

  ZeroMemory(@fo, SizeOf(fo));
  fo.Wnd := Handle;
  fo.wFunc := FO_COPY;
  fo.pFrom := PChar(AStream.FileName+#0);
  fo.pTo := PChar(DestName+#0);
  fo.fFlags := FOF_SILENT or FOF_NOCONFIRMATION or FOF_NOERRORUI or FOF_NOCONFIRMMKDIR or FOF_RENAMEONCOLLISION or FOF_WANTMAPPINGHANDLE;

  if SHFileOperation(fo) <> 0 then
  begin
    // error handling...
  end else
  begin
    if fo.fAnyOperationsAborted then
    begin
      // abort handling...
    end;

    if fo.hNameMappings <> nil then
    begin
      try
        pMappings := PHandleToMappings(fo.hNameMappings);
        pMapping := pMappings^.lpSHNameMappings[0];
        SetString(DestName, pMapping^.pszNewPath, pMapping^.cchNewPath);
      finally
        SHFreeNameMappings(THandle(fo.hNameMappings));
      end;
      // use DestName as needed...
    end;
  end;

  ModalResult := mrOk;
end;

在Vista及更高版本中，您也可以改为使用IFileOperation.CopyItem()，它也支持在碰撞时重命名项目。如果发生重命名冲突，可以使用IFileOperationProgressSink回调来发现新文件名。

例如：

uses
  ..., Winapi.ActiveX, Winapi.ShlObj, System.Win.Comobj;

type
  TMyCopyProgressSink = class(TInterfacedObject, IFileOperationProgressSink)
  public
    CopiedName: string;
    function StartOperations: HResult; stdcall;
    function FinishOperations(hrResult: HResult): HResult; stdcall;
    function PreRenameItem(dwFlags: DWORD; const psiItem: IShellItem;
      pszNewName: LPCWSTR): HResult; stdcall;
    function PostRenameItem(dwFlags: DWORD; const psiItem: IShellItem;
      pszNewName: LPCWSTR; hrRename: HResult; const psiNewlyCreated: IShellItem): HResult; stdcall;
    function PreMoveItem(dwFlags: DWORD; const psiItem: IShellItem;
      const psiDestinationFolder: IShellItem; pszNewName: LPCWSTR): HResult; stdcall;
    function PostMoveItem(dwFlags: DWORD; const psiItem: IShellItem;
      const psiDestinationFolder: IShellItem; pszNewName: LPCWSTR;
      hrMove: HResult; const psiNewlyCreated: IShellItem): HResult; stdcall;
    function PreCopyItem(dwFlags: DWORD; const psiItem: IShellItem;
      const psiDestinationFolder: IShellItem; pszNewName: LPCWSTR): HResult; stdcall;
    function PostCopyItem(dwFlags: DWORD; const psiItem: IShellItem;
      const psiDestinationFolder: IShellItem; pszNewName: LPCWSTR;
      hrCopy: HResult; const psiNewlyCreated: IShellItem): HResult; stdcall;
    function PreDeleteItem(dwFlags: DWORD; const psiItem: IShellItem): HResult; stdcall;
    function PostDeleteItem(dwFlags: DWORD; const psiItem: IShellItem; hrDelete: HResult;
      const psiNewlyCreated: IShellItem): HResult; stdcall;
    function PreNewItem(dwFlags: DWORD; const psiDestinationFolder: IShellItem;
      pszNewName: LPCWSTR): HResult; stdcall;
    function PostNewItem(dwFlags: DWORD; const psiDestinationFolder: IShellItem;
      pszNewName: LPCWSTR; pszTemplateName: LPCWSTR; dwFileAttributes: DWORD;
      hrNew: HResult; const psiNewItem: IShellItem): HResult; stdcall;
    function UpdateProgress(iWorkTotal: UINT; iWorkSoFar: UINT): HResult; stdcall;
    function ResetTimer: HResult; stdcall;
    function PauseTimer: HResult; stdcall;
    function ResumeTimer: HResult; stdcall;
  end;

function TMyCopyProgressSink.StartOperations: HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.FinishOperations(hrResult: HResult): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PreRenameItem(dwFlags: DWORD; const psiItem: IShellItem;
  pszNewName: LPCWSTR): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PostRenameItem(dwFlags: DWORD; const psiItem: IShellItem;
  pszNewName: LPCWSTR; hrRename: HResult; const psiNewlyCreated: IShellItem): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PreMoveItem(dwFlags: DWORD; const psiItem: IShellItem;
  const psiDestinationFolder: IShellItem; pszNewName: LPCWSTR): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PostMoveItem(dwFlags: DWORD; const psiItem: IShellItem;
  const psiDestinationFolder: IShellItem; pszNewName: LPCWSTR;
  hrMove: HResult; const psiNewlyCreated: IShellItem): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PreCopyItem(dwFlags: DWORD; const psiItem: IShellItem;
  const psiDestinationFolder: IShellItem; pszNewName: LPCWSTR): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PostCopyItem(dwFlags: DWORD; const psiItem: IShellItem;
  const psiDestinationFolder: IShellItem; pszNewName: LPCWSTR;
  hrCopy: HResult; const psiNewlyCreated: IShellItem): HResult; stdcall;
begin
  CopiedName := pszNewName;
  Result := S_OK;
end;

function TMyCopyProgressSink.PreDeleteItem(dwFlags: DWORD; const psiItem: IShellItem): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PostDeleteItem(dwFlags: DWORD; const psiItem: IShellItem; hrDelete: HResult;
  const psiNewlyCreated: IShellItem): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PreNewItem(dwFlags: DWORD; const psiDestinationFolder: IShellItem;
  pszNewName: LPCWSTR): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PostNewItem(dwFlags: DWORD; const psiDestinationFolder: IShellItem;
  pszNewName: LPCWSTR; pszTemplateName: LPCWSTR; dwFileAttributes: DWORD;
  hrNew: HResult; const psiNewItem: IShellItem): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.UpdateProgress(iWorkTotal: UINT; iWorkSoFar: UINT): HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.ResetTimer: HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.PauseTimer: HResult; stdcall;
begin
  Result := S_OK;
end;

function TMyCopyProgressSink.ResumeTimer: HResult; stdcall;
begin
  Result := S_OK;
end;

procedure TsomeForm.UniFileUpload1Completed(Sender: TObject; AStream: TFileStream);
var
  DestName : string;
  DestFolder : string;
  pfo : IFileOperation;
  psiFrom : IShellItem;
  psiTo : IShellItem;
  Sink : IFileOperationProgressSink;
  bAborted : BOOL;
begin
  DestFolder := UniServerModule.StartPath + 'files\' + UniMainModule.foldername + '\';
  DestName := UniMainModule.FirstName + '_' + UniMainModule.LastName + '.pdf';

  try
    OleCheck(SHCreateItemFromParsingName(PChar(AStream.FileName), nil, IShellItem, psiFrom));
    OleCheck(SHCreateItemFromParsingName(PChar(DestFolder), nil, IShellItem, psiTo));

    OleCheck(CoCreateInstance(CLSID_FileOperation, nil, CLSCTX_ALL, IFileOperation, pfo));
    OleCheck(pfo.SetOperationFlags(FOF_SILENT or FOF_NOCONFIRMATION or FOF_NOCONFIRMMKDIR or FOF_NOERRORUI or FOF_RENAMEONCOLLISION or FOFX_PRESERVEFILEEXTENSIONS));

    Sink := TMyCopyProgressSink.Create;
    OleCheck(pfo.CopyItem(psiFrom, psiTo, PChar(DestName), Sink));
    OleCheck(pfo.PerformOperations());

    pfo.GetAnyOperationsAborted(bAborted);
    if bAborted then
    begin
      // abort handling...
    end;

    DestName := TMyCopyProgressSink(Sink).CopiedName;
    // use DestName as needed...
  except
    // error handling...
  end;
end;

Answer 2

您有一个文件名，因此请使用FileExists检查文件是否存在。如果它确实将（1）附加到文件名并再试一次。重复增加n，直到得到不存在的文件名。所以，有点像这样：

procedure TsomeForm.UniFileUpload1Completed(Sender: TObject; AStream: TFileStream);
var
  DestName : string;
  DestFolder : string;
  n : integer;
  additional : string;
begin
   DestFolder:=UniServerModule.StartPath+'files\'+UniMainModule.foldername+'\';
   DestName:=DestFolder+UniMainModule.FirstName+'_'+UniMainModule.LastName;
   n := 0;
   additional :='.pdf';
   while FileExists( DestName + additional ) do
   begin
     inc(n);
     additional := '(' + intToStr(n) + ')'+'.pdf';
   end;
   CopyFile(PChar(AStream.FileName), PChar(DestName + additional), False);
   ModalResult:= mrOk;
end;

Answer 3

以下是我对解决方案的看法

    procedure TsomeForm.UniFileUpload1Completed(Sender: TObject; AStream: TFileStream);
    var
      DestName, NewName : string;
      DestFolder : string;
      Cnt: integer;
    begin
      DestFolder:=UniServerModule.StartPath+'files\'+UniMainModule.foldername+'\';
      DestName:=DestFolder+UniMainModule.FirstName+'_'+UniMainModule.LastName+'.pdf';
      if FileExists(DestName) then begin
        Cnt:=0;
        repeat
          Inc(Cnt);
          NewName:=Format(DestFolder+UniMainModule.FirstName+'_'+UniMainModule.LastName+'(%d).pdf',[Cnt]);
        until not FileExists(NewName);
        DestName:=NewName;
      end;
      CopyFile(PChar(AStream.FileName), PChar(DestName), False);
      ModalResult:= mrOk;
    end;

CopyFile - 保存而不覆盖现有文件

3 个答案: