主要應用了:
1. 手動建立控制項及釋放;
2. 繫結控制項事件;
**如下:
unit uformmain;
inte***ce
uses
windows, messages, sysutils, variants, classes, graphics, controls, forms,
dialogs, stdctrls, extctrls, comctrls;
const calccount = 5;
type
tformmain = class(tform)
edtexpression: tedit;
pnlnum: tpanel;
btnclose: tbutton;
pnlcalc: tpanel;
btnclear: tbutton;
stat1: tstatusbar;
btnbackspace: tbutton;
procedure formcreate(sender: tobject);
procedure formdestroy(sender: tobject);
procedure btnnumclick(sender: tobject);
procedure btncalcclick(sender: tobject);
procedure btnclearclick(sender: tobject);
procedure btncloseclick(sender: tobject);
procedure edtexpressionkeypress(sender: tobject; var key: char);
procedure btnbackspaceclick(sender: tobject);
private
public
btnnum: array[0..9] of tbutton;
btncalc: array[0..calccount - 1] of tbutton;
end;
const
calcopts: array[0..calccount - 1] of char = ('+', '-', '*', '/', '=');
var formmain: tformmain;
result: integer = 0;
opt: char; // perior operator
implementation
procedure tformmain.btncalcclick(sender: tobject);
var c: char;
begin
if edtexpression.text ='' then exit;
:= edtexpression.text + (sender as tbutton).caption;
c := (sender as tbutton).caption[1];
if opt <> '' then
begin
case opt of
'+':
begin
result := result + strtoint(edtexpression.text);
end;
'-':
begin
result := result - strtoint(edtexpression.text);
end;
'*':
begin
result := result * strtoint(edtexpression.text);
end;
'/':
begin
if strtoint(edtexpression.text) = 0 then exit;
result := result div strtoint(edtexpression.text);
end;
'=':
begin
end;
end;
endelse
result := strtoint(edtexpression.text);
if (c <> '=') then
begin
edtexpression.text := '0';
endelse
edtexpression.text := inttostr(result);
opt := c;
stat1.******text := inttostr(result);
end;
procedure tformmain.btnnumclick(sender: tobject);
begin
edtexpression.text := inttostr(strtoint(edtexpression.text) * 10
+ strtoint((sender as tbutton).caption));
end;
procedure tformmain.formcreate(sender: tobject);
var i: integer;
begin
for i := low(btnnum) to high(btnnum) do
begin
btnnum[i] := tbutton.create(self);
with btnnum[i] do
begin
parent := pnlnum;
left := 20 + (i mod 3) * 50;
top := 10 + ( i div 3) * 40;
width := 30;
height := 30;
caption := inttostr((i+1) mod 10);
onclick := btnnumclick;
end;
end;
// 初始化運算子鍵
for i := 0 to calccount - 1 do
begin
btncalc[i] := tbutton.create(self);
with btncalc[i] do
begin
parent := pnlcalc;
left := 10;
top := 5 + i * 35;
width := 30;
height := 30;
caption := calcopts[i];
font.size := 12;
font.style := font.style + [fsbold];
onclick := btncalcclick;
end;
end;
stat1.******panel := true;
edtexpression.text := '0';
end;
procedure tformmain.formdestroy(sender: tobject);
var i: integer;
begin
for i := low(btnnum) to high(btnnum) do
begin
if assigned(btnnum[i]) then
freeandnil(btnnum);
end;
for i := low(btncalc) to high(btncalc) do
begin
if assigned(btncalc[i]) then
freeandnil(btncalc);
end;
end;
procedure tformmain.btnclearclick(sender: tobject);
begin
edtexpression.text := '0';
result := 0;
stat1.******text := inttostr(result);
end;
procedure tformmain.btncloseclick(sender: tobject);
begin
close;
end;
procedure tformmain.edtexpressionkeypress(sender: tobject; var key: char);
begin
if not (key in ['0' .. '9']) then key := #0;
end;
procedure tformmain.btnbackspaceclick(sender: tobject);
begin
edtexpression.text := inttostr(strtoint(edtexpression.text) div 10);
end;
end.
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