如果我从GotFocus事件处理程序中调用SelectAll,它对鼠标不起作用——鼠标一释放,选择就消失了。
编辑:人们喜欢唐纳利的回答,我将试着解释为什么我不像公认的答案那样喜欢它。
It is more complex, while the accepted answer does the same thing in a simpler way.
The usability of accepted answer is better. When you click in the middle of the text, text gets unselected when you release the mouse allowing you to start editing instantly, and if you still want to select all, just press the button again and this time it will not unselect on release. Following Donelle's recipe, if I click in the middle of text, I have to click second time to be able to edit. If I click somewhere within the text versus outside of the text, this most probably means I want to start editing instead of overwriting everything.
在谷歌搜索和测试之后,我找到了一个简单的解决方案。
你需要在容器窗口的Loaded事件中添加一个事件处理程序:
private void yourwindow_Loaded(object sender, RoutedEventArgs e)
{
EventManager.RegisterClassHandler(typeof(TextBox),
TextBox.PreviewMouseLeftButtonDownEvent,
new RoutedEventHandler(SelectivelyIgnoreMouseButton));
}
接下来,你必须创建之前代码中引用的RoutedEventHandler的处理程序:
private void SelectivelyIgnoreMouseButton(object sender, RoutedEventArgs e)
{
TextBox tb = (sender as TextBox);
if (tb != null)
{
if (!tb.IsKeyboardFocusWithin)
{
e.Handled = true;
tb.Focus();
}
}
}
现在,你可以单独将GotFocus事件处理程序上的SelectAll()命令添加到任何TextBox控件:
private void myTextBox_GotFocus(object sender, RoutedEventArgs e)
{
(sender as TextBox).SelectAll();
}
您的文本现在被选中对焦!
改编自博士WPF解决方案,MSDN论坛
不知道为什么它在GotFocus事件中失去了选择。
但是一个解决方案是在GotKeyboardFocus和GotMouseCapture事件上进行选择。这样它就能一直工作。
——编辑——
在这里添加一个例子来告诉人们如何解决上面提到的一些缺点:
private void TextBox_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
// Fixes issue when clicking cut/copy/paste in context menu
if (textBox.SelectionLength == 0)
textBox.SelectAll();
}
private void TextBox_LostMouseCapture(object sender, MouseEventArgs e)
{
// If user highlights some text, don't override it
if (textBox.SelectionLength == 0)
textBox.SelectAll();
// further clicks will not select all
textBox.LostMouseCapture -= TextBox_LostMouseCapture;
}
private void TextBox_LostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
// once we've left the TextBox, return the select all behavior
textBox.LostMouseCapture += TextBox_LostMouseCapture;
}
我认为这很有效:
private void ValueText_GotFocus(object sender, RoutedEventArgs e)
{
TextBox tb = (TextBox)e.OriginalSource;
tb.Dispatcher.BeginInvoke(
new Action(delegate
{
tb.SelectAll();
}), System.Windows.Threading.DispatcherPriority.Input);
}
如果你想实现它作为一个扩展方法:
public static void SelectAllText(this System.Windows.Controls.TextBox tb)
{
tb.Dispatcher.BeginInvoke(
new Action(delegate
{
tb.SelectAll();
}), System.Windows.Threading.DispatcherPriority.Input);
}
在GotFocus事件中:
private void ValueText_GotFocus(object sender, RoutedEventArgs e)
{
TextBox tb = (TextBox)e.OriginalSource;
tb.SelectAllText();
}
我发现上面的解决方案是因为几个月前我正在寻找一种方法来将焦点设置到给定的UIElement上。我在某处发现了下面的代码(特此给予),它工作得很好。尽管它与OP的问题没有直接关系,但我还是发布了它,因为它演示了使用Dispatcher处理UIElement的相同模式。
// Sets focus to uiElement
public static void DelayedFocus(this UIElement uiElement)
{
uiElement.Dispatcher.BeginInvoke(
new Action(delegate
{
uiElement.Focusable = true;
uiElement.Focus();
Keyboard.Focus(uiElement);
}),
DispatcherPriority.Render);
}
这个简单的实现非常适合我:
void TextBox_GotFocus(object sender, RoutedEventArgs e)
{
((TextBox) sender).SelectAll();
}
void TextBox_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
var TextBox = (TextBox) sender;
if (!TextBox.IsKeyboardFocusWithin)
{
TextBox.Focus();
e.Handled = true;
}
}
把它应用到所有的文本框,把下面的代码InitializeComponent();
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.GotFocusEvent, new RoutedEventHandler(TextBox_GotFocus));
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.PreviewMouseDownEvent, new MouseButtonEventHandler(TextBox_PreviewMouseDown));