//方法1:
procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
if not (Key in ['0'..'9']) then
Key := Chr(0);
end;
//方法2:
procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
if not (Byte(Key) in [48..57]) then // 0的 Ascii 是 48
Key := Chr(0);
end;
//方法3:
procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
if not CharInSet(Key, ['1'..'5']) then Key := #0;
end;
//Edit 文本的选择与光标位置
procedure TForm1.Button1Click(Sender: TObject);
begin
Edit1.SetFocus; //给于焦点
SendMessage(Edit1.Handle,EM_SETSEL,0,1); //选择第一个字符
SendMessage(Edit1.Handle,EM_SETSEL,0,-1); //全选
SendMessage(Edit1.Handle,EM_SETSEL,1,1); //光标移到第一个字符后面
SendMessage(Edit1.Handle,EM_SETSEL,0,0); //光标移到开始
SendMessage(Edit1.Handle,EM_SETSEL,-1,0); //光标移到开始
end;