unit Unit1;interfaceuses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;type
TForm1 = class(TForm)
Edit1: TEdit;
Edit2: TEdit;
Button1: TButton;
Edit3: TEdit;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public { Public declarations }
end;var
Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);
var
first,second:integer;
begin
if novalue(edit1) or novalue(edit2) then
exit
else
begin
first:=strtoint(edit1.text);
second:=strtoint(edit2.text);
edit3.text:=inttostr(first+second);
end;end;function novalue(testedit:tedit):boolean;
begin
if testedit.text='' then
begin
result:=true;
showmessage('请输入数字');
end
else
result:=false;
end;end.
以上是我想计算两个edit.text相加的问题,函数novalue是判断edit 中是否有数值,如果没有数值提示出错,由数值则进行计算。函数我已经写好了,如果把novalue放到button方法的前面,则不出错,并能执行,但是如果放到后面,就出错,我知道在使用这个自定义的函数之前一定要声明一下,问题就是我不知道应该把function novalue(testedit:tedit):boolean;放在那里进行声明,我放在public里好像不对,应该放到哪里?
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;type
TForm1 = class(TForm)
Edit1: TEdit;
Edit2: TEdit;
Button1: TButton;
Edit3: TEdit;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public { Public declarations }
end;var
Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);
var
first,second:integer;
begin
if novalue(edit1) or novalue(edit2) then
exit
else
begin
first:=strtoint(edit1.text);
second:=strtoint(edit2.text);
edit3.text:=inttostr(first+second);
end;end;function novalue(testedit:tedit):boolean;
begin
if testedit.text='' then
begin
result:=true;
showmessage('请输入数字');
end
else
result:=false;
end;end.
以上是我想计算两个edit.text相加的问题,函数novalue是判断edit 中是否有数值,如果没有数值提示出错,由数值则进行计算。函数我已经写好了,如果把novalue放到button方法的前面,则不出错,并能执行,但是如果放到后面,就出错,我知道在使用这个自定义的函数之前一定要声明一下,问题就是我不知道应该把function novalue(testedit:tedit):boolean;放在那里进行声明,我放在public里好像不对,应该放到哪里?
这样function novalue(testedit:tedit):boolean;implementation
type
TForm1 = class(TForm)
Edit1: TEdit;
Edit2: TEdit;
Button1: TButton;
Edit3: TEdit;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
function novalue(testedit:tedit):boolean;
public { Public declarations }
end;function TForm1.novalue(testedit:tedit):boolean;
begin
if testedit.text='' then
begin
result:=true;
showmessage('请输入数字');
end
else
result:=false;
end;