当MultiLine属性为True时，全选快捷方式将失败 [英] Select All shortcut fails when MultiLine property is True

问题描述

我有一个Windows窗体应用程序，上面有一个标准的TextBox.表单上没有事件被处理，也没有菜单.当我按下 Ctrl + A 快捷方式以选择所有文本时，我得到一个叮当声，但未选择任何内容.

I have a Windows forms application that has a standard TextBox on it. There are no events being handled and no menus on the form. When I press the Ctrl+A shortcut to select all the text, I get a ding, and nothing is selected.

为确认我没有无意编写某些代码，我创建了一个新的Windows窗体应用程序，该窗体上只有一个文本框.我用C#和VB.Net都尝试过，两者都一样.我已经在Windows 7上运行的Visual Studio 2012 Update 1和Windows XP上运行的Visual Studio 2008中进行了尝试，它在每个实例中的行为都相同.

To confirm I didn't inadvertently code something I created a new Windows forms application with only a textbox on the form. I tried it with both C# and VB.Net and it is the same in both. I have tried this in Visual Studio 2012 Update 1 running on Windows 7, and Visual Studio 2008 running on Windows XP and it behaves the same in each instance.

我可以很容易地在KeyDown事件中捕获按键组合，但是即使在设置e.Cancel = true之后，机器仍然会发出叮"的声音.

I can catch the key stroke combination in the KeyDown event easily enough, but even after setting e.Cancel = true the machine stills sounds the "ding".

是否有一种抑制声音的方法，或者甚至更好的一种方法，可以使文本框接受快捷方式，就像非多行文本框一样?

Is there a way to suppress the sound, or even better, a way to make the textbox accept the shortcut the same way a non-multiline textbox does?

推荐答案

这对许多程序员来说都是一个惊喜，但是当它处于多行模式时，本机Windows编辑控件实际上并未将Ctrl + A作为快捷方式实现.它必须由使用它的程序来实现.例如，您可以在记事本中看到此内容，该程序使用多行编辑控件.使用文件+打开+文件，选择c:\ windows \ notepad.exe，打开Accelerator节点，然后双击其中一张表.

This is a surprise to many programmers but the native Windows edit control doesn't actually implement Ctrl+A as a shortcut when it is in multi-line mode. It has to be implemented by the program that uses it. You can see this for example in Notepad, a program that uses a multi-line edit control. Use File + Open + File, select c:\windows\notepad.exe, open the Accelerator node and double-click one of the tables.

实施起来并不困难:

    private void textBox1_KeyDown(object sender, KeyEventArgs e) {
        if (e.KeyData == (Keys.Control | Keys.A)) {
            textBox1.SelectAll();
            e.Handled = e.SuppressKeyPress = true;
        }
    }

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更新:在.NET 4.6.1中进行了更改，System.Windows.Forms.TextBox现在也为多行文本框实现了Ctrl + A.

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UPDATE: changed in .NET 4.6.1, System.Windows.Forms.TextBox now implements Ctrl+A for multi-line textboxes as well.

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