delphi 下如何删除以某个扩展名结尾的文件？？

Question

即如何删除某文件夹下 *.txt的文件呢 ？

Answer 1

删除一子目录及其下面的文件 
    The following example demonstrates deleting all the files in a directory and then the directory itself. Additional processing would be required to delete read only files and files that are in use. procedure TForm1.Button1Click(Sender: TObject);
var
    DirInfo: TSearchRec;
    r : Integer;
begin
    r := FindFirst('C:\Download\Test\*.*', FaAnyfile, DirInfo);
    while r = 0 do
        begin
            if ((DirInfo.Attr and FaDirectory <> FaDirectory) and
               (DirInfo.Attr and FaVolumeId <> FaVolumeID)) then
                  if DeleteFile(pChar('C:\Download\test\' + DirInfo.Name)) = false then
                     ShowMessage('Unable to delete : C:\Download\test\' + DirInfo.Name);
            r := FindNext(DirInfo);
        end;
    SysUtils.FindClose(DirInfo);
    if RemoveDirectory('C:\Download\Test') = false then
        ShowMessage('Unable to delete direcotry : C:\Download\test');
end;

Answer 2

procedure TForm1.Button2Click(Sender: TObject);
var
  sr: TSearchRec;
begin
  if FindFirst('c:\winnt', faAnyFile or faArchive or faVolumeID, sr) = 0 then
  begin
    repeat
      if LowerCase (ExtractFileExt (sr.Name)) = '.txt' then
        DeleteFile (sr.Name);
    until FindNext(sr) <> 0;
    FindClose(sr);
  end;
end;

Answer 3

//删除目录下的某种类型的文件，支持通配符
Function DeleteFileOneType(ADirctory:string;
                           AFileName:string;
                           ASubDirectory:Boolean):boolean;
var
   lpFileOp: TSHFileOpStruct;
   FromDir:PChar;
   ToDir:PChar;
   f:TSearchRec;
begin
   if AsubDirectory then//包括子目录
   begin
      GetMem(FromDir, Length(ADirctory+'\'+AFileName)+2);
      GetMem(ToDir, Length(ADirctory)+2);
      Try
         FillChar(FromDir^, Length(ADirctory+'\'+AFileName)+2, 0);
         FillChar(ToDir^, Length(ADirctory)+2, 0);
         StrCopy(FromDir, PChar(ADirctory+'\'+AFileName));
         StrCopy(ToDir, PChar(ADirctory));
         lpFileop.wFunc:=FO_DELETE;
         lpFileop.Wnd:=Application.Handle;
         lpFileop.pFrom:=FromDir;
         lpFileop.pTo:=ToDir;
         lpFileop.fFlags:=FOF_NOCONFIRMMKDIR or FOF_NOCONFIRMATION  or FOF_FILESONLY or FOF_NOERRORUI;
         lpFileop.fAnyOperationsAborted := False;
         lpFileop.hNameMappings := nil;
         lpFileop.lpszProgressTitle := nil;
         Result:=SHFileOperation(lpFileop)=0;
      Finally
         FreeMem(ToDir,Length(ADirctory)+2);
         FreeMem(FromDir,Length(ADirctory+'\'+AFileName)+2);
      end;
   end
   else  //不包括子目录
   begin
      Result:=false;
      if FindFirst(ADirctory+'\'+AFileName,$0000003F,f)=0 then
      begin
         Result:=DeleteFile(ADirctory+'\'+f.Name);
         while FindNext(f) = 0 do
             DeleteFile(ADirctory+'\'+f.Name);
        FindClose(f);
      end;
   end;
end;

Answer 4

procedure FDeleteTmpFile(AExtName: string);  //删除临时文件
  var
    F : TSearchRec;
    ResultValue : integer;
  begin
    ResultValue := FindFirst(FGetTmpPath + '\*.' + AExtName, faAnyFile, F);
    while ResultValue = 0 do
    begin
      if (F.Attr <> faDirectory) and (Pos(AExtName, F.Name) > 0) then
        DeleteFile(FGetTmpPath + '\' + F.Name);
      ResultValue := FindNext(F);
    end;
  end;