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Ограничение размера Memo


Ограничение длины и количества строк компонента:

    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.
[000642]



Содержание раздела