procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char); begin if key=#13 then begin try if (strtoint(edit1.text)<1) or (strtoint(edit1.text)>255) then edit1.Clear; except on e:exception do begin showmessage(e.message); end; end; end; end;
procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char); begin if not (key in ['0'..'9',#8,#13]) then key :=#0; if key=#13 then begin try if (strtoint(edit1.text)<1) or (strtoint(edit1.text)>255) then begin edit1.Clear; edit1.SetFocus; end; except on e:exception do begin showmessage(e.message); end; end; end; end;
procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
if key=#13 then
begin
try
if (strtoint(edit1.text)<1) or (strtoint(edit1.text)>255) then
edit1.Clear;
except on e:exception do
begin
showmessage(e.message);
end;
end;
end;
end;
procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
if not (key in ['0'..'9',#8,#13]) then key :=#0;
if key=#13 then
begin
try
if (strtoint(edit1.text)<1) or (strtoint(edit1.text)>255) then
begin
edit1.Clear;
edit1.SetFocus;
end;
except
on e:exception do
begin
showmessage(e.message);
end;
end;
end;
end;
2、“事后”判断:内容变化或提交前校验