让 Edit 只接受数字《转》

//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;