Question

delphi edit1,edit2文本框用代码清空,然后点击button1时,显示两个不能为空,请输入数字

实现了1到100的自动求和.但突然有了以上想法,不知道代码应该如何写回在哪?delphi刚学...
procedure TForm1.Button1Click(Sender: TObject);
var
i,s:integer;
begin

s := 0;
for i:= StrToInt(Edit1.text) to StrToInt(Edit2.text) do
// for i:= StrToInt(Edit1.Caption) to StrToInt(Edit2.caption) do
begin
s := s + i ;
end;
ShowMessage(IntToStr(s));
end;

Answer 1

procedure TForm1.Button1Click(Sender: TObject);
var
i,s:integer;
begin
if Edit1.Text='' then begin
ShowMessage('Edit1不能为空,请输入数字');
Exit;
end;
if Edit2.Text='' then begin
ShowMessage('Edit2不能为空,请输入数字');
Exit;
end;
s := 0;
for i:= StrToInt(Edit1.text) to StrToInt(Edit2.text) do
// for i:= StrToInt(Edit1.Caption) to StrToInt(Edit2.caption) do
begin
s := s + i ;
end;
ShowMessage(IntToStr(s));
end;