//判断文件是否存在 FileExists
var
f: string;
begin
f := 'c:\temp\test.txt';
if not FileExists(f) then
begin
//如果文件不存在
end;
end;

--------------------------------------------------------------------------------


//判断文件夹是否存在 DirectoryExists
var
dir: string;
begin
dir := 'c:\temp';
if not DirectoryExists(dir) then
begin
//如果文件夹不存在
end;
end;

--------------------------------------------------------------------------------


//删除文件 DeleteFile; Windows.DeleteFile
var
f: string;
begin
f := 'c:\temp\test.txt';
//DeleteFile(f); //返回 Boolean

//或者用系统API:
Windows.DeleteFile(PChar(f)); //返回 Boolean
end;

--------------------------------------------------------------------------------


//删除文件夹 RemoveDir; RemoveDirectory
var
dir: string;
begin
dir := 'c:\temp';
RemoveDir(dir); //返回 Boolean

//或者用系统 API:
RemoveDirectory(PChar(dir)); //返回 Boolean
end;

--------------------------------------------------------------------------------


//获取当前文件夹 GetCurrentDir
var
dir: string;
begin
dir := GetCurrentDir;
ShowMessage(dir); //C:\Documents and Settings\wy\My Documents\RAD Studio\Projects
end;

--------------------------------------------------------------------------------


//设置当前文件夹 SetCurrentDir; ChDir; SetCurrentDirectory
var
dir: string;
begin
dir := 'c:\temp';
if SetCurrentDir(dir) then
ShowMessage(GetCurrentDir); //c:\temp

//或者
ChDir(dir); //无返回值

//也可以使用API:
SetCurrentDirectory(PChar(Dir)); //返回 Boolean
end;

--------------------------------------------------------------------------------


//获取指定驱动器的当前路径名 GetDir
var
dir: string;
b: Byte;
begin
b := 0;
GetDir(b,dir);
ShowMessage(dir); //

//第一个参数: 1、2、3、4...分别对应: A、B、C、D...
//0 是缺省驱动器
end;

--------------------------------------------------------------------------------


//文件改名 RenameFile
var
OldName,NewName: string;
begin
OldName := 'c:\temp\Old.txt';
NewName := 'c:\temp\New.txt';

if RenameFile(OldName,NewName) then
ShowMessage('改名成功!');

//也可以:
SetCurrentDir('c:\temp');
OldName := 'Old.txt';
NewName := 'New.txt';

if RenameFile(OldName,NewName) then
ShowMessage('改名成功!');
end;

--------------------------------------------------------------------------------


//建立文件夹 CreateDir; CreateDirectory; ForceDirectories
var
dir: string;
begin
dir := 'c:\temp\delphi';
if not DirectoryExists(dir) then
CreateDir(dir); //返回 Boolean

//也可以直接用API:
CreateDirectory(PChar(dir),nil); //返回 Boolean

//如果缺少上层目录将自动补齐:
dir := 'c:\temp\CodeGear\Delphi\2007\万一';
ForceDirectories(dir); //返回 Boolean
end;

--------------------------------------------------------------------------------


//删除空文件夹 RemoveDir; RemoveDirectory
var
dir: string;
begin
dir := 'c:\temp\delphi';
RemoveDir(dir); //返回 Boolean

//也可以直接用API:
RemoveDirectory(PChar(dir)); //返回 Boolean
end;

--------------------------------------------------------------------------------


//建立新文件 FileCreate
var
FileName: string;
i: Integer;
begin
FileName := 'c:\temp\test.dat';
i := FileCreate(FileName);

if i>0 then
ShowMessage('新文件的句柄是: ' + IntToStr(i))
else
ShowMessage('创建失败!');
end;

--------------------------------------------------------------------------------


//获取当前文件的版本号 GetFileVersion
var
s: string;
i: Integer;
begin
s := 'C:\WINDOWS\notepad.exe';
i := GetFileVersion(s); //如果没有版本号返回 -1
ShowMessage(IntToStr(i)); //327681 这是当前记事本的版本号(还应该再转换一下)
end;

--------------------------------------------------------------------------------


//获取磁盘空间 DiskSize; DiskFree
var
r: Real;
s: string;
begin
r := DiskSize(3); //获取C:总空间, 单位是字节
r := r/1024/1024/1024;
Str(r:0:2,s); //格式为保留两位小数的字符串
s := 'C盘总空间是: ' + s + ' GB';
ShowMessage(s); //xx.xx GB

r := DiskFree(3); //获取C:可用空间
r := r/1024/1024/1024;
Str(r:0:2,s);
s := 'C盘可用空间是: ' + s + ' GB';
ShowMessage(s); //xx.xx GB
end;

//查找一个文件 FileSearch
var
FileName,Dir,s: string;
begin
FileName := 'notepad.exe';
Dir := 'c:\windows';
s := FileSearch(FileName,Dir);

if s<>'' then
ShowMessage(s) //c:\windows\notepad.exe
else
ShowMessage('没找到');
end;
--------------------------------------------------------------------------------

//搜索文件 FindFirst; FindNext; FindClose
var
sr: TSearchRec; //定义 TSearchRec 结构变量
Attr: Integer; //文件属性
s: string; //要搜索的内容
List: TStringList; //存放搜索结果
begin
s := 'c:\windows\*.txt';
Attr := faAnyFile; //文件属性值faAnyFile表示是所有文件
List := TStringList.Create; //List建立

if FindFirst(s,Attr,sr)=0 then //开始搜索,并给 sr 赋予信息, 返回0表示找到第一个
begin
repeat //如果有第一个就继续找
List.Add(sr.Name); //用List记下结果
until(FindNext(sr)<>0); //因为sr已经有了搜索信息, FindNext只要这一个参数, 返回0表示找到
end;
FindClose(sr); //需要结束搜索, 搜索是内含句柄的

ShowMessage(List.Text); //显示搜索结果
List.Free; //释放List

//更多注释:
//TSearchRec 结构是内涵文件大小、名称、属性与时间等信息
//TSearchRec 中的属性是一个整数值, 可能的值有:
//faReadOnly 1 只读文件
//faHidden 2 隐藏文件
//faSysFile 4 系统文件
//faVolumeID 8 卷标文件
//faDirectory 16 目录文件
//faArchive 32 归档文件
//faSymLink 64 链接文件
//faAnyFile 63 任意文件

//s 的值也可以使用?通配符,好像只支持7个?, 如果没有条件就是*, 譬如: C:\*
//实际使用中还应该在 repeat 中提些条件, 譬如判断如果是文件夹就递归搜索等等
end;
--------------------------------------------------------------------------------

//读取与设置文件属性 FileGetAttr; FileSetAttr
var
FileName: string;
Attr: Integer; //属性值是一个整数
begin
FileName := 'c:\temp\Test.txt';
Attr := FileGetAttr(FileName);
ShowMessage(IntToStr(Attr)); //32, 存档文件

//设置为隐藏和只读文件:
Attr := FILE_ATTRIBUTE_READONLY or FILE_ATTRIBUTE_HIDDEN;
if FileSetAttr(FileName,Attr)=0 then //返回0表示成功
ShowMessage('设置成功!');

//属性可选值(有些用不着):
//FILE_ATTRIBUTE_READONLY = 1; 只读
//FILE_ATTRIBUTE_HIDDEN = 2; 隐藏
//FILE_ATTRIBUTE_SYSTEM = 4; 系统
//FILE_ATTRIBUTE_DIRECTORY = 16
//FILE_ATTRIBUTE_ARCHIVE = 32; 存档
//FILE_ATTRIBUTE_DEVICE = 64
//FILE_ATTRIBUTE_NORMAL = 128; 一般
//FILE_ATTRIBUTE_TEMPORARY = 256
//FILE_ATTRIBUTE_SPARSE_FILE = 512
//FILE_ATTRIBUTE_REPARSE_POINT = 1204
//FILE_ATTRIBUTE_COMPRESSED = 2048; 压缩
//FILE_ATTRIBUTE_OFFLINE = 4096
//FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 8192; 不被索引
//FILE_ATTRIBUTE_ENCRYPTED = 16384
end;
--------------------------------------------------------------------------------

//获取文件的创建时间 FileAge; FileDateToDateTime
var
FileName: string;
ti: Integer;
dt: TDateTime;
begin
FileName := 'c:\temp\Test.txt';
ti := FileAge(FileName);
ShowMessage(IntToStr(ti)); //返回: 931951472, 需要转换

dt := FileDateToDateTime(ti); //转换
ShowMessage(DateTimeToStr(dt)); //2007-12-12 14:27:32
end;
--------------------------------------------------------------------------------
//判断文件是否存在 FileExistsvarf: string;beginf := 'c:\temp\test.txt';if not FileExists(f) thenbegin //如果文件不存在end;end;=================
function FileExists(const FileName: string): Boolean;{$IFDEF MSWINDOWS}beginResult := FileAge(FileName) <> -1;end;{$ENDIF}{$IFDEF LINUX}beginResult := euidaccess(PChar(FileName), F_OK) = 0;end;{$ENDIF}
--------------------------------------------------------------------------------
//判断文件夹是否存在 DirectoryExistsvardir: string;begindir := 'c:\temp';if not DirectoryExists(dir) thenbegin //如果文件夹不存在end;end;==================function DirectoryExists(const Directory: string): Boolean;{$IFDEF LINUX}varst: TStatBuf;beginif stat(PChar(Directory), st) = 0 then Result := S_ISDIR(st.st_mode)else Result := False;end;{$ENDIF}{$IFDEF MSWINDOWS}varCode: Integer;beginCode := GetFileAttributes(PChar(Directory));Result := (Code <> -1) and (FILE_ATTRIBUTE_DIRECTORY and Code <> 0);end;{$ENDIF}-------------------------------------------------------------------------------- //删除文件 DeleteFile; Windows.DeleteFilevarf: string;beginf := 'c:\temp\test.txt';//DeleteFile(f); //返回 Boolean//或者用系统API:Windows.DeleteFile(PChar(f)); //返回 Booleanend;======================function DeleteFile(const FileName: string): Boolean;begin{$IFDEF MSWINDOWS}Result := Windows.DeleteFile(PChar(FileName));{$ENDIF}{$IFDEF LINUX}Result := unlink(PChar(FileName)) <> -1;{$ENDIF}end; --------------------------------------------------------------------------------
//删除文件夹 RemoveDir; RemoveDirectoryvardir: string;begindir := 'c:\temp';RemoveDir(dir); //返回 Boolean//或者用系统 API:RemoveDirectory(PChar(dir)); //返回 Booleanend;========================function RemoveDir(const Dir: string): Boolean;begin{$IFDEF MSWINDOWS}Result := RemoveDirectory(PChar(Dir));{$ENDIF}{$IFDEF LINUX}Result := __rmdir(PChar(Dir)) = 0;{$ENDIF}end;
--------------------------------------------------------------------------------
//获取当前文件夹 GetCurrentDirvardir: string;begindir := GetCurrentDir;ShowMessage(dir); //C:\Documents and Settings\wy\My Documents\RAD Studio\Projectsend;=============function GetCurrentDir: string;beginGetDir(0, Result);end;
--------------------------------------------------------------------------------
//设置当前文件夹 SetCurrentDir; ChDir; SetCurrentDirectory
var
dir: string;
begin
dir := 'c:\temp';
if SetCurrentDir(dir) then
ShowMessage(GetCurrentDir); //c:\temp

//或者
ChDir(dir); //无返回值

//也可以使用API:
SetCurrentDirectory(PChar(Dir)); //返回 Boolean
end;

=====================

function SetCurrentDir(const Dir: string): Boolean;
begin
{$IFDEF MSWINDOWS}
Result := SetCurrentDirectory(PChar(Dir));
{$ENDIF}
{$IFDEF LINUX}
Result := __chdir(PChar(Dir)) = 0;
{$ENDIF}
end;


--------------------------------------------------------------------------------
//建立文件夹 CreateDir; CreateDirectory; ForceDirectoriesvardir: string;begindir := 'c:\temp\delphi';if not DirectoryExists(dir) then CreateDir(dir); //返回 Boolean//也可以直接用API:CreateDirectory(PChar(dir),nil); //返回 Boolean//如果缺少上层目录将自动补齐:dir := 'c:\temp\CodeGear\Delphi\2007\万一';ForceDirectories(dir); //返回 Booleanend;==================function CreateDir(const Dir: string): Boolean;begin{$IFDEF MSWINDOWS}Result := CreateDirectory(PChar(Dir), nil);{$ENDIF}{$IFDEF LINUX}Result := __mkdir(PChar(Dir), mode_t(-1)) = 0;{$ENDIF}end;
--------------------------------------------------------------------------------
//建立新文件 FileCreatevarFileName: string;i: Integer;beginFileName := 'c:\temp\test.dat';i := FileCreate(FileName);if i>0 then ShowMessage('新文件的句柄是: ' + IntToStr(i))else ShowMessage('创建失败!');end;=================function FileCreate(const FileName: string): Integer;{$IFDEF MSWINDOWS}beginResult := Integer(CreateFile(PChar(FileName), GENERIC_READ or GENERIC_WRITE, 0, nil, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0));end;{$ENDIF}{$IFDEF LINUX}beginResult := FileCreate(FileName, FileAccessRights);end;{$ENDIF}
--------------------------------------------------------------------------------
//文件改名 RenameFilevarOldName,NewName: string;beginOldName := 'c:\temp\Old.txt';NewName := 'c:\temp\New.txt';if RenameFile(OldName,NewName) then ShowMessage('改名成功!');//也可以:SetCurrentDir('c:\temp');OldName := 'Old.txt';NewName := 'New.txt';if RenameFile(OldName,NewName) then ShowMessage('改名成功!');end;=====================function RenameFile(const OldName, NewName: string): Boolean;begin{$IFDEF MSWINDOWS}Result := MoveFile(PChar(OldName), PChar(NewName));{$ENDIF}{$IFDEF LINUX}Result := __rename(PChar(OldName), PChar(NewName)) = 0;{$ENDIF}end;
--------------------------------------------------------------------------------
//获取文件的创建时间FileAge function FileAge(const FileName: string): Integer;{$IFDEF MSWINDOWS}varHandle: THandle;FindData: TWin32FindData;LocalFileTime: TFileTime;beginHandle := FindFirstFile(PChar(FileName), FindData);if Handle <> INVALID_HANDLE_VALUE thenbegin Windows.FindClose(Handle); if (FindData.dwFileAttributes and FILE_ATTRIBUTE_DIRECTORY) = 0 then begin FileTimeToLocalFileTime(FindData.ftLastWriteTime, LocalFileTime); if FileTimeToDosDateTime(LocalFileTime, LongRec(Result).Hi, LongRec(Result).Lo) then Exit; end;end;Result := -1;end;{$ENDIF}{$IFDEF LINUX}varst: TStatBuf;beginif stat(PChar(FileName), st) = 0 then Result := st.st_mtimeelse Result := -1;end;{$ENDIF}
--------------------------------------------------------------------------------
//读取与设置文件属性 FileGetAttr; FileSetAttr
var
FileName: string;
Attr: Integer; //属性值是一个整数
begin
FileName := 'c:\temp\Test.txt';
Attr := FileGetAttr(FileName);
ShowMessage(IntToStr(Attr)); //32, 存档文件

//设置为隐藏和只读文件:
Attr := FILE_ATTRIBUTE_READONLY or FILE_ATTRIBUTE_HIDDEN;
if FileSetAttr(FileName,Attr)=0 then //返回0表示成功
ShowMessage('设置成功!');

//属性可选值(有些用不着):
//FILE_ATTRIBUTE_READONLY = 1; 只读
//FILE_ATTRIBUTE_HIDDEN = 2; 隐藏
//FILE_ATTRIBUTE_SYSTEM = 4; 系统
//FILE_ATTRIBUTE_DIRECTORY = 16
//FILE_ATTRIBUTE_ARCHIVE = 32; 存档
//FILE_ATTRIBUTE_DEVICE = 64
//FILE_ATTRIBUTE_NORMAL = 128; 一般
//FILE_ATTRIBUTE_TEMPORARY = 256
//FILE_ATTRIBUTE_SPARSE_FILE = 512
//FILE_ATTRIBUTE_REPARSE_POINT = 1204
//FILE_ATTRIBUTE_COMPRESSED = 2048; 压缩
//FILE_ATTRIBUTE_OFFLINE = 4096
//FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 8192; 不被索引
//FILE_ATTRIBUTE_ENCRYPTED = 16384
end;

===================

function FileGetAttr(const FileName: string): Integer;
begin
Result := GetFileAttributes(PChar(FileName));
end;

function FileSetAttr(const FileName: string; Attr: Integer): Integer;
begin
Result := 0;
if not SetFileAttributes(PChar(FileName), Attr) then
Result := GetLastError;
end;
{$ENDIF}

function FileSetAttr(const FileName: string; Attr: Integer): Integer;
begin
Result := 0;
if not SetFileAttributes(PChar(FileName), Attr) then
Result := GetLastError;
end;
{$ENDIF}


--------------------------------------------------------------------------------


//获取磁盘空间 DiskSize; DiskFreevarr: Real;s: string;beginr := DiskSize(3); //获取C:总空间, 单位是字节r := r/1024/1024/1024;Str(r:0:2,s); //格式为保留两位小数的字符串s := 'C盘总空间是: ' + s + ' GB';ShowMessage(s); //xx.xx GBr := DiskFree(3); //获取C:可用空间r := r/1024/1024/1024;Str(r:0:2,s);s := 'C盘可用空间是: ' + s + ' GB';ShowMessage(s); //xx.xx GBend;=====================function DiskSize(Drive: Byte): Int64;varFreeSpace: Int64;beginif not InternalGetDiskSpace(Drive, Result, FreeSpace) then Result := -1;end;{$ENDIF}function DiskFree(Drive: Byte): Int64;varTotalSpace: Int64;beginif not InternalGetDiskSpace(Drive, TotalSpace, Result) then Result := -1;end;
--------------------------------------------------------------------------------
//查找一个文件 FileSearchvarFileName,Dir,s: string;beginFileName := 'notepad.exe';Dir := 'c:\windows';s := FileSearch(FileName,Dir);if s<>'' then ShowMessage(s) //c:\windows\notepad.exeelse ShowMessage('没找到');end;=================function FileSearch(const Name, DirList: string): string;varI, P, L: Integer;C: Char;beginResult := Name;P := 1;L := Length(DirList);while True dobegin if FileExists(Result) then Exit; while (P <= L) and (DirList[P] = PathSep) do Inc(P); if P > L then Break; I := P; while (P <= L) and (DirList[P] <> PathSep) do begin if DirList[P] in LeadBytes then P := NextCharIndex(DirList, P) else Inc(P); end; Result := Copy(DirList, I, P - I); C := AnsiLastChar(Result)^; if (C <> DriveDelim) and (C <> PathDelim) then Result := Result + PathDelim; Result := Result + Name;end;Result := '';end;
--------------------------------------------------------------------------------
//获取当前文件的版本号 GetFileVersionvars: string;i: Integer;begins := 'C:\WINDOWS\notepad.exe';i := GetFileVersion(s); //如果没有版本号返回 -1ShowMessage(IntToStr(i)); //327681 这是当前记事本的版本号(还应该再转换一下)end;===============function GetFileVersion(const AFileName: string): Cardinal;varFileName: string;InfoSize, Wnd: DWORD;VerBuf: Pointer;FI: PVSFixedFileInfo;VerSize: DWORD;beginResult := Cardinal(-1);// GetFileVersionInfo modifies the filename parameter data while parsing.// Copy the string const into a local variable to create a writeable copy.FileName := AFileName;UniqueString(FileName);InfoSize := GetFileVersionInfoSize(PChar(FileName), Wnd);if InfoSize <> 0 thenbegin GetMem(VerBuf, InfoSize); try if GetFileVersionInfo(PChar(FileName), Wnd, InfoSize, VerBuf) then if VerQueryValue(VerBuf, '\', Pointer(FI), VerSize) then Result:= FI.dwFileVersionMS; finally FreeMem(VerBuf); end;end;end;
--------------------------------------------------------------------------------
//获取指定驱动器的当前路径名 GetDirvardir: string;b: Byte;beginb := 0;GetDir(b,dir);ShowMessage(dir); ////第一个参数: 1、2、3、4...分别对应: A、B、C、D...//0 是缺省驱动器end;
--------------------------------------------------------------------------------
//ChangeFileExt 更改文件的后缀扩展名
函数说明 更改指定文件的扩展名,函数原型如下:
delphi中源码
function ChangeFileExt(const FileName, Extension: string): string;
//第一个参数为要修改的文件名，可以带路径
//第二个参数为修改后的后缀名
//该函数返回修改后的文件名
var
I: Integer;
begin
I := LastDelimiter('.' + PathDelim + DriveDelim,Filename);
if (I = 0) or (FileName[I] <> '.') then I := MaxInt;
Result := Copy(FileName, 1, I - 1) + Extension;
end;

比如:
s:=changefileext('f:\123.txt','.ini');
showmessage(s);//f:\123.ini

=============

function ChangeFileExt(const FileName, Extension: string): string;
var
I: Integer;
begin
I := LastDelimiter('.' + PathDelim + DriveDelim,Filename);
if (I = 0) or (FileName[I] <> '.') then I := MaxInt;
Result := Copy(FileName, 1, I - 1) + Extension;
end;