限制Memo的行数和行宽
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;
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;
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