unit Unit1;
interface
uses
SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
StdCtrls, ExtCtrls, Forms;
type
TForm1 = class(TForm)
Memo1: TMemo;
procedure FormCreate(Sender: TObject);
procedure Memo1KeyPress(Sender: TObject; var Key: Char);
public
MaxCharsPerLine, MaxLines: Integer;
function MemoLine: Integer;
function LineLen(r: Integer): Integer;
function NRows: Integer;
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
function TForm1.NRows: Integer;
begin
with Memo1 do
Result := 1 + SendMessage(Handle, EM_LINEFROMCHAR, GetTextLen - 1, 0);
end;
function TForm1.LineLen(r: Integer): Integer;
var
r1, r2: Integer;
begin
with Memo1 do
begin
r1 := SendMessage(Handle, EM_LINEINDEX, r, 0);
if (r > NRows - 1) then
r2 := SendMessage(Handle, EM_LINEINDEX, r + 1, 0) - 2 {-CR/LF}
else
r2 := GetTextLen;
end;
Result := r2 - r1;
end;
function TForm1.MemoLine: Integer;
begin
with Memo1 do
Result := SendMessage(Handle, EM_LINEFROMCHAR, SelStart, 0);
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
MaxCharsPerLine := 8;
MaxLines := 4;
end;
procedure TForm1.Memo1KeyPress(Sender: TObject; var Key: Char);
begin
with Memo1 do
begin
case Key of
' '..#255: if (LineLen(MemoLine) >= MaxCharsPerLine) then
Key := #0;
#10, #13: if (NRows >= MaxLines) then
Key := #0;
#8: if (SelStart = SendMessage(Handle, EM_LINEINDEX, MemoLine, 0)) then
Key := #0;
end;
end;
end;
end.
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Ограничение длины и количества строк компонента Memo