按钮从文本框中删除焦点c＃ [英] Button takes away focus from the text box c#

问题描述

你好，



我用c＃中的按钮制作了一个键盘（触摸屏）我想写按钮点击功能作为退格键但每次按下backspace我专注的texbox失去了它的焦点创建错误只需键盘就好了

Hello,

I have made a keyboard(touchscreen) out of buttons in c# I want to write the function for button click as backspace but every time I press backspace my focused texbox loosing its focus creating errors working with just keyboard it fine

int index = focusedTextbox.SelectionStart;
            focusedTextbox.Text = focusedTextbox.Text.Remove(focusedTextbox.SelectionStart - 1, 1);
            focusedTextbox.Select(index - 1, 1)

谢谢你的帮助

thank you for your help

推荐答案

当然它会带走焦点。问题有点棘手。我不知道你正在使用什么UI框架/库，但我为 System.Windows.Forms 提供了一个全面的解决方案：

应用程序焦点的输入和丢失 [ ^ ]。



如果你需要别的东西，请解释一下。



另一种方法，更通用的方法就是这样：因为虚拟键盘的目的是为了如果没有物理键盘，通过鼠标或触摸屏，您根本不需要键盘焦点和导航。因此，您可以构建纯粹不可聚焦元素的键盘，而不是按钮。它可以是 Panel ，或者，对于WPF， TextBlock ， Border 与否。 甚至按钮可以变得不可聚焦;请阅读按钮类型的MSDN文档。 [结束编辑]



现在，如果您通过任何更改需要创建系统范围的虚拟键盘，则需要使用 SendInput 。为了以防万一，请查看我过去对该主题的回答：

如何在WPF按钮点击按键按键事件 [ 3 ]，

如何在WPF按钮上点击按键的按键事件 [ 1 ]，
创建虚拟键盘 [ ^ ]，

重点关注应用程序失败 [ ^ ]，

在BACKSPACE按钮上编程 [ ^ ] 。

-SA

Of course it will take away focus. The problem is somewhat tricky. I don't know what UI framework/library you are using, but I provided one comprehensive resolution for System.Windows.Forms:
Application focus getting and losing[^].

If you need something else, please explain.

Another approach, more universal one, would be this: as the purpose of virtual keyboard is to be used without a physical keyboard, through a mouse or touch screen, you don't need keyboard focus and navigation at all. So, you can compose your keyboard of purely non-focusable elements, not buttons. It can be Panel, or, with WPF, TextBlock, with Border or not. And even Button can be made non-focusable; please read the MSDN documentation on your button type. [END EDIT]

Now, if you, by any change, need to create a system-wide virtual keyboard, you would need to use SendInput. Just in case, please see my past answers on the topic:
How to fire a Key Press event of a Key on button click in WPF [3],
How to fire a Key Press event of a Key on button click in WPF [1],
Creating a Virtual Keyboard[^],
Application focus getting and losing[^],
Programming on BACKSPACE button[^].

—SA

ButtonClickEventHandler(....)
{
string text = focusedtextbox.Text;
string newText = text.Substring(0, text.Length - 1);
Dispatcher.CurrentDispatcher.BeginInvoke(() => focusedtextbox.text = newText);
Dispatcher.CurrentDispatcher.BeginInvoke(() => focusedtextbox.Focus());
}

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