;of text: '''');
Readln(s);
Writeln(''''You typed: '''',s);
Writeln(''''Hit <Enter> to exit'''');
Readln;
end;
-----------------------------------------------------------------------------
SeekEof 测试档案是否结束.
-----------------------------------------------------------------------------
Unit System
函数原型 function SeekEof [ (var F: Text) ]: Boolean;
范例 var
f : System.TextFile;
i, j, Y : Integer;
begin
AssignFile(f,''''TEST.TXT'''');
Rewrite(f);
{ Create a file with 8 numbers and some whitespace at the
ends of the lines }
Writeln(f,''''1 2 3 4 '''');
Writeln(f,''''5 6 7 8 '''');
Reset(f);
{ Read the numbers back. SeekEoln returns TRUE if there are
no more numbers on the current line; SeekEof returns
TRUE if there is no more text (other than whitespace) in
the file. }
Y := 5;
while not SeekEof(f) do
begin
if SeekEoln(f) then
Readln; { Go to next line }
Read(f,j);
Canvas.TextOut(5, Y, IntToStr(j));
Y := Y + Canvas.TextHeight(IntToStr(j)) + 5;
end;
end;
-----------------------------------------------------------------------------
SeekEoln 测试档案中行是否结束.
-----------------------------------------------------------------------------
Unit System
函数原型 function SeekEoln [ (var F: Text) ]: Boolean;
Example
var
f : System.TextFile;
i, j, Y : Integer;
begin
AssignFile(f,''''TEST.TXT'''');
Rewrite(f);
{ Create a file with 8 numbers and some
whitespace at the ends of the lines }
Writeln(f,''''1 2 3 4 '''');
Writeln(f,''''5 6 7 8 '''');
Reset(f);
{ Read the numbers back. SeekEoln returns TRUE if there are no more
numbers on the current line; SeekEof returns TRUE if there is no
more text (other than whitespace) in the file. }
Y := 5;
while not SeekEof(f) do
begin
if SeekEoln(f) then
Readln; { Go to next line }
Read(f,j);
Canvas.TextOut(5, Y, IntToStr(j));
Y := Y + Canvas.TextHeight(IntToStr(j)) + 5;
end;
end;
## SeekEoln, SeekEof Example
-----------------------------------------------------------------------------
SetTextBuf 指定 I/O buffer 给 text file.
-----------------------------------------------------------------------------
Unit System
函数原型 procedure SetTextBuf(var F: Text; var Buf [ ; Size: Integer] );
范例 uses Dialogs;
var
F, FTwo: System.TextFile;
Ch: Char;
Buf: array[1..4095] of Char; { 4K buffer }
begin
if OpenDialog1.Execute then
begin
AssignFile(F, ParamStr(1));
{ Bigger buffer for faster reads }
SetTextBuf(F, Buf);
Reset(F);
{ Dump text file into another file }
AssignFile(FTwo, ''''WOOF.DOG'''');
Rewrite(FTwo);
while not Eof(f) do
begin
Read(F, Ch);
Write(FTwoCh);
end;
System.CloseFile(F);
System.CloseFile(FTwo);
end;
end;
-----------------------------------------------------------------------------
Write 写入档案.
-----------------------------------------------------------------------------
Unit System
函数原型 Write(F, V1,...,Vn);
Write( [var F: Text; ] P1 [ , P2,..., Pn] );
procedure TForm1.Button3Click(Sender: TObject);
var
Stream: TBlobStream;
S: string;
begin
with Table1 do
begin
Edit;
Stream := CreateBlobStream(FieldByName(''''Notes''''), bmReadWrite);
try
Stream.Seek(0, 2); {Seek 0 bytes from the stream''''s end point}
S := '''' This line will be added to the end.'''';
Stream.Write(PChar(S), Length(S));
finally
Stream.Free;
end;
Post;
end;
end;
-----------------------------------------------------------------------------
Writeln 写入档案.
-----------------------------------------------------------------------------
Unit System
函数原型 procedure Writeln([ var F: Text; ] P1 [, P2, ...,Pn ] );
范例 var
s : string;
begin
Write(''''Enter a line of text: '''');
Readln(s);
Writeln(''''You typed: '''',s);
Writeln(''''Hit <Enter> to exit'''');
Readln;
end;
=======================================
Transfer routines 转换函式
=======================================
Chr 将 Byte 转为字元.
-----------------------------------------------------------------------------
Unit System
函数原型 function Chr(X: Byte): Char;
范例 begin
Canvas.TextOut(10, 10, Chr(65)); { The letter ''''A''''}
end;
Example
procedure TForm1.ComboBox1KeyPress(Sender: TObject; var Key: Char);
var
Found: boolean;
i,SelSt: Integer;
TmpStr: string;
begin
{ first, process the keystroke to obtain the current string }
{ This code requires all items in list to be uppercase}
if Key in [''''a''''..''''z''''] then Dec(Key,32); {Force Uppercase only!}
with (Sender as TComboBox) do
begin
SelSt := SelStart;
if (Key = Chr(vk_Back)) and (SelLength <> 0) then
TmpStr := Copy(Text,1,SelStart)+Copy(Text,SelLength+SelStart+1,255)
else if Key = Chr(vk_Back) then << 上一页 [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] ... 下一页 >> |
