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📄 help-function.txt

📁 DELPHI常用函数集及简要范例集
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			  S: String;
			  FileDate1:Integer;
			  DateTime1:TDateTime;
			begin
			  FileDate1 := FileAge('c:\delphi_d\delphi_help1.txt');
			  DateTime1 := FileDateToDateTime(FileDate1);
			  S := DateTimeToStr(DateTime1);
			  Label1.Caption:=S;
			end;
--------------------------------------------------------
FileDateToDateTime	将DOS型态的日期时间转换为TDateTime型态.
--------------------------------------------------------
Unit		SysUtils
函数原型	function FileDateToDateTime(FileDate: Integer):TDateTime;
-----------------------------------------------------------------------------
DateTimeToFileDate	将TDateTime型态的日期时间转换为	DOS型态.
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function DateTimeToFileDate(DateTime: TDateTime):Integer;
FileGetDate		传回档案的日期及时间(DOS型态).
Unit		SysUtils
函数原型	function FileGetDate(Handle: Integer): Integer;
说明		就是档案总管中档案内容裹面的修改日期.
范例		procedure TForm1.Button1Click(Sender: TObject);
			var
			  FileHandle:Integer;
			  S: String;
			  FileDate1:Integer;
			  DateTime1:TDateTime;
			begin
			  FileHandle :=FileOpen('c:\delphi_d\delphi_help2.txt',
				fmOpenReadWrite);
			  if FileHandle > 0 then
				Begin
					FileDate1 := FileGetDate(FileHandle);
					DateTime1 := FileDateToDateTime(FileDate1);
					S := DateTimeToStr(DateTime1);
					FileClose(FileHandle);
				End
			  else
					S := 'Open File Error';
			  Label1.Caption:=S;
			end;
-----------------------------------------------------------------------------
FileSetDate		设定档案的日期及时间(DOS型态).
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function FileSetDate(Handle: Integer; Age: Integer):	Integer;
说明		传回值为0表示成功.
-----------------------------------------------------------------------------
DeleteFile			删除档案
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function DeleteFile(const FileName: string): Boolean;
范例 一	DeleteFile('DELETE.ME');

范例 二           if FileExists(FileName) then
                        if MessageDlg('Do you really want to delete ' +  
                           ExtractFileName(FileName) + '?'), []) = IDYes then 
                            DeleteFile(FileName);
##FileExists, DeleteFile Example
-----------------------------------------------------------------------------
RenameFile		更改档名
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function RenameFile(const OldName, NewName: string):Boolean;
范例               
 procedure TForm1.Button1Click(Sender: TObject);
var
  BackupName: string;
  FileHandle: Integer;
  StringLen: Integer;
  X: Integer;
  Y: Integer;
begin
  if SaveDialog1.Execute then
  begin
    if FileExists(SaveDialog1.FileName) then
    begin
      BackupName := ExtractFileName(SaveDialog1.FileName);
      BackupName := ChangeFileExt(BackupName, '.BAK');
      if not RenameFile(SaveDialog1.FileName, BackupName) then
        raise Exception.Create('Unable to create backup file.');
    end;
    FileHandle := FileCreate(SaveDialog1.FileName);
    { Write out the number of rows and columns in the grid. }
    FileWrite(FileHandle, 
      StringGrid1.ColCount, SizeOf(StringGrid1.ColCount));
    FileWrite(FileHandle, 
      StringGrid1.RowCount, SizeOf(StringGrid1.RowCount));
    for X := 0 to StringGrid1.ColCount ? 1 do
    begin
      for Y := 0 to StringGrid1.RowCount ? 1 do
      begin
        { Write out the length of each string, followed by the string itself. }
        StringLen := Length(StringGrid1.Cells[X,Y]);
        FileWrite(FileHandle, StringLen, SizeOf(StringLen));
        FileWrite(FileHandle,
          StringGrid1.Cells[X,Y], Length(StringGrid1.Cells[X,Y]);
      end;
    end;
    FileClose(FileHandle);
  end;
end;
-----------------------------------------------------------------------------
DiskFree			磁碟机剩馀空间(Bytes)
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function DiskFree(Drive: Byte): Integer;
范例		var
			  S: string;
			begin
			  S := IntToStr(DiskFree(0) div 1024) + ' Kbytes free.';
			  Label1.Caption:=S;
			end;
说明		Drive 
			0=目前磁碟机,1=A磁碟机,2=B磁碟机...传回值若为-1,表示磁碟机侦测错误.
范例
var
  S: string;
  AmtFree: Int64;
  Total:   Int64;
begin
  AmtFree := DiskFree(0);
  Total := DiskSize(0);
  S := IntToStr(AmtFree div Total) + 'percent of the space on drive 0 is free: ' (AmtFree div 1024) + ' Kbytes free. ';
  Canvas.TextOut(10, 10, S);
end;
##DiskFree, DiskSize Example
-----------------------------------------------------------------------------
DiskSize			磁碟机空间大小(Bytes)
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function DiskSize(Drive: Byte): Integer;
范例		var
			  S: string;
			begin
			  S := IntToStr(DiskSize(0) div 1024) + ' Kbytes free.';
			  Label1.Caption:=S;
			end;
说明		Drive 
			0=目前磁碟机,1=A磁碟机,2=B磁碟机....传回值若为-1,表示磁碟机侦测错误.
##DiskFree, DiskSize Example
-----------------------------------------------------------------------------
FileExists			判断档案是否存在.
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function FileExists(const FileName: string): Boolean;
类似                FileExists, RenameFile, FileCreate, FileWrite, FileClose, ExtractFileName Example
范例
procedure TForm1.Button1Click(Sender: TObject);
var
  BackupName: string;
  FileHandle: Integer;
  StringLen: Integer;
  X: Integer;
  Y: Integer;
begin
  if SaveDialog1.Execute then
  begin
    if FileExists(SaveDialog1.FileName) then
    begin
      BackupName := ExtractFileName(SaveDialog1.FileName);
      BackupName := ChangeFileExt(BackupName, '.BAK');
      if not RenameFile(SaveDialog1.FileName, BackupName) then
        raise Exception.Create('Unable to create backup file.');
    end;
    FileHandle := FileCreate(SaveDialog1.FileName);
    { Write out the number of rows and columns in the grid. }
    FileWrite(FileHandle, 
      StringGrid1.ColCount, SizeOf(StringGrid1.ColCount));
    FileWrite(FileHandle, 
      StringGrid1.RowCount, SizeOf(StringGrid1.RowCount));
    for X := 0 to StringGrid1.ColCount ? 1 do
    begin
      for Y := 0 to StringGrid1.RowCount ? 1 do
      begin
        { Write out the length of each string, followed by the string itself. }
        StringLen := Length(StringGrid1.Cells[X,Y]);
        FileWrite(FileHandle, StringLen, SizeOf(StringLen));
        FileWrite(FileHandle,
          StringGrid1.Cells[X,Y], Length(StringGrid1.Cells[X,Y]);
      end;
    end;
    FileClose(FileHandle);
  end;
end;
##FileExists, DeleteFile Example
##FileExists, RenameFile, FileCreate, FileWrite, FileClose, ExtractFileName Example
-----------------------------------------------------------------------------
FileOpen			开档.
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function FileOpen(const FileName: string; Mode: 
				Integer):Integer;
****		开档失败传回-1.
说明		以下有关档案读取都属低阶,如Dos Int 21h中有关档案的部
			分.
			fmOpenRead			= $0000;
			fmOpenWrite			= $0001;
			fmOpenReadWrite		= $0002;
			fmShareCompat		= $0000;
			fmShareExclusive		= $0010;
			fmShareDenyWrite		= $0020;
			fmShareDenyRead		= $0030;
			fmShareDenyNone		= $0040;

			fmOpenRead			Open for read access only.
			FmOpenWrite			Open for write access only.
			FmOpenReadWrite		Open for read and write access.
			fmShareCompat		Compatible with the way FCBs are 
								opened.
			fmShareExclusive		Read and write access is denied.
			fmShareDenyWrite		Write access is denied.
			fmShareDenyRead		Read access is denied.
			fmShareDenyNone		Allows full access for others.
范例
procedure OpenForShare(const FileName: String);
var
  FileHandle : Integer;
begin
  FileHandle := FileOpen(FileName, fmOpenWrite or fmShareDenyNone);
  if FileHandle > 0 then
    {valid file handle}
  else
    {Open error: FileHandle = negative DOS error code}
end;
范例
procedure TForm1.Button1Click(Sender: TObject);
var
  iFileHandle: Integer;
  iFileLength: Integer;
  iBytesRead: Integer;
  Buffer: PChar;
  i: Integer
begin
  if OpenDialog1.Execute then
  begin
    try
      iFileHandle := FileOpen(OpenDialog1.FileName, fmOpenRead);
      iFileLength := FileSeek(iFileHandle,0,2);
      FileSeek(iFileHandle,0,0);
      Buffer := PChar(AllocMem(iFileLength + 1));
      iBytesRead = FileRead(iFileHandle, Buffer, iFileLength);
      FileClose(iFileHandle);
      for i := 0 to iBytesRead-1 do
      begin
        StringGrid1.RowCount := StringGrid1.RowCount + 1;
        StringGrid1.Cells[1,i+1] := Buffer[i];
        StringGrid1.Cells[2,i+1] := IntToStr(Integer(Buffer[i]));
      end;
    finally
      FreeMem(Buffer);
    end;
  end;
end;
##FileOpen, FileSeek, FileRead Example
-----------------------------------------------------------------------------
FileCreate			建档
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function FileCreate(const FileName: string): Integer;

范例
procedure TForm1.Button1Click(Sender: TObject);
var
  BackupName: string;
  FileHandle: Integer;
  StringLen: Integer;
  X: Integer;
  Y: Integer;
begin
  if SaveDialog1.Execute then
  begin
    if FileExists(SaveDialog1.FileName) then
    begin
      BackupName := ExtractFileName(SaveDialog1.FileName);
      BackupName := ChangeFileExt(BackupName, '.BAK');
      if not RenameFile(SaveDialog1.FileName, BackupName) then

        raise Exception.Create('Unable to create backup file.');
    end;
    FileHandle := FileCreate(SaveDialog1.FileName);
    { Write out the number of rows and columns in the grid. }
    FileWrite(FileHandle, 
      StringGrid1.ColCount, SizeOf(StringGrid1.ColCount));
    FileWrite(FileHandle, 
      StringGrid1.RowCount, SizeOf(StringGrid1.RowCount));
    for X := 0 to StringGrid1.ColCount ? 1 do
    begin

      for Y := 0 to StringGrid1.RowCount ? 1 do
      begin
        { Write out the length of each string, followed by the string itself. }
        StringLen := Length(StringGrid1.Cells[X,Y]);
        FileWrite(FileHandle, StringLen, SizeOf(StringLen));
        FileWrite(FileHandle,
          StringGrid1.Cells[X,Y], Length(StringGrid1.Cells[X,Y]);
      end;
    end;
    FileClose(FileHandle);
  end;

end;
##FileExists, RenameFile, FileCreate, FileWrite, FileClose, ExtractFileName Example
-----------------------------------------------------------------------------
FileClose			关档
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	procedure FileClose(Handle: Integer);
范例
procedure TForm1.Button1Click(Sender: TObject);
var
  BackupName: string;
  FileHandle: Integer;
  StringLen: Integer;
  X: Integer;
  Y: Integer;
begin
  if SaveDialog1.Execute then
  begin
    if FileExists(SaveDialog1.FileName) then
    begin
      BackupName := ExtractFileName(SaveDialog1.FileName);
      BackupName := ChangeFileExt(BackupName, '.BAK');
      if not RenameFile(SaveDialog1.FileName, BackupName) then
        raise Exception.Create('Unable to create backup file.');
    end;
    FileHandle := FileCreate(SaveDialog1.FileName);
    { Write out the number of rows and columns in the grid. }
    FileWrite(FileHandle, 
      StringGrid1.ColCount, SizeOf(StringGrid1.ColCount));
    FileWrite(FileHandle, 
      StringGrid1.RowCount, SizeOf(StringGrid1.RowCount));
    for X := 0 to StringGrid1.ColCount ? 1 do
    begin
      for Y := 0 to StringGrid1.RowCount ? 1 do
      begin
        { Write out the length of each string, followed by the string itself. }
        StringLen := Length(StringGrid1.Cells[X,Y]);
        FileWrite(FileHandle, StringLen, SizeOf(StringLen));
        FileWrite(FileHandle,
          StringGrid1.Cells[X,Y], Length(StringGrid1.Cells[X,Y]);
      end;
    end;
    FileClose(FileHandle);
  end;
end;
##FileExists, RenameFile, FileCreate, FileWrite, FileClose, ExtractFileName Example

============================================
****		它是以Handle为叁数.
============================================
FileRead			读取档案
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function FileRead(Handle: Integer; var Buffer; Count: Integer):Integer;
范例
procedure TForm1.Button1Click(Sender: TObject);

var
  iFileHandle: Integer;
  iFileLength: Integer;
  iBytesRead: Integer;
  Buffer: PChar;
  i: Integer
begin
  if OpenDialog1.Execute then
  begin
    try
      iFileHandle := FileOpen(OpenDialog1.FileName, fmOpenRead);
      iFileLength := FileSeek(iFileHandle,0,2);
      FileSeek(iFileHandle,0,0);
      Buffer := PChar(AllocMem(iFileLength + 1));
      iBytesRead = FileRead(iFileHandle, Buffer, iFileLength);
      FileClose(iFileHandle);
      for i := 0 to iBytesRead-1 do
      begin
        StringGrid1.RowCount := StringGrid1.RowCount + 1;
        StringGrid1.Cells[1,i+1] := Buffer[i];
        StringGrid1.Cells[2,i+1] := IntToStr(Integer(Buffer[i]));
      end;
    finally
      FreeMem(Buffer);
    end;
  end;
end;
##FileOpen, FileSeek, FileRead Example
-----------------------------------------------------------------------------
FileWrite			写入档案
-----------------------------------------------------------------------------
Unit		SysUtils
函数原型	function FileWrite(Handle: Integer; const Buffer; Count: Integer): Integer;
范例
procedure TForm1.Button1Click(Sender: TObject);
var
  BackupName: string;
  FileHandle: Integer;
  StringLen: Integer;
  X: Integer;
  Y: Integer;
begin
  if SaveDialog1.Execute then
  begin
    if FileExists(SaveDialog1.FileName) then
    begin
      BackupName := ExtractFileName(SaveDialog1.FileName);
      BackupName := ChangeFileExt(BackupName, '.BAK');
      if not RenameFile(SaveDialog1.FileName, BackupName) then
        raise Exception.Create('Unable to create backup file.');
    end;
    FileHandle := FileCreate(SaveDialog1.FileName);
    { Write out the number of rows and columns in the grid. }
    FileWrite(FileHandle, 
      StringGrid1.ColCount, SizeOf(StringGrid1.ColCount));
    FileWrite(FileHandle, 
      StringGrid1.RowCount, SizeOf(StringGrid1.RowCount));
    for X := 0 to StringGrid1.ColCount  do
    begin
12345

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