如何在 Perl Tk 中更改标签中的数据? [英] How do I change the data in a label in Perl Tk?

问题描述

我正在尝试使用 Tk 创建一个程序，该程序将从条目中获取数据，然后单击按钮创建一个包含该数据的标签.

I'm trying to create a program with Tk that will take the data from an entry, and, at the click of a button, create a label that has that data.

下面是我一直在调试的代码.在调试过程中，我试过tb]geh如下:

Below is the code I've been debugging. In the process of debugging, I have tried tb]geh following:

• 使用对$printItem的引用
• 将子程序连接到 -command 转到子程序
• 以各种方式结合上述内容

use Tk; use strict; use warnings;

$mw = MainWindow -> new;

my $printItem = $mw -> Entry(-width = 20); $printItem -> pack;

$mw -> Button(-text => "Write.", -command => sub{ $mw -> Label(-text => "$printItem") -> pack} -> pack;

MainLoop;

当我点击按钮时，标签显示的是Tk::Entry=HASH([这里似乎是随机的十六进制数]).这显然不是我想要的，我想知道如何才能达到我想要的效果.

When I click the button, all that the label shows is Tk::Entry=HASH([seemingly random hexadecimal number here]). This is obviously not what I want, and I'd like to know how I can get the effect I desire.

推荐答案

Tk::Entry=HASH(0xdeadbeef) 是 Perl 字符串化对象的方式.事实上，你的 $printItem 变量存储了一个 Tk::Entry 类的对象:

Tk::Entry=HASH(0xdeadbeef) is how Perl stringifies objects. And indeed, your $printItem variable stores an object of class Tk::Entry:

my $printItem = $mw -> Entry(-width = 20);

从 Tk::Entry 小部件获取字符串，你可以使用它的 get 方法:

To get the string from a Tk::Entry widget, you can use its get method:

... -command => sub { $mw->Label(-text => $printItem->get)->pack } ...

完整的工作示例:

use strict;
use warnings;
use Tk;

my $mw = MainWindow->new;

my $printItem = $mw->Entry(-width => 20); $printItem->pack;

$mw->Button(-text => "Write.", -command => sub { $mw->Label(-text => $printItem->get)->pack })->pack;

MainLoop;

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