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.
我使用了Nils的答案，但将其转换为更灵活的答案。
public enum SelectAllMode
{
/// <summary>
/// On first focus, it selects all then leave off textbox and doesn't check again
/// </summary>
OnFirstFocusThenLeaveOff = 0,
/// <summary>
/// On first focus, it selects all then never selects
/// </summary>
OnFirstFocusThenNever = 1,
/// <summary>
/// Selects all on every focus
/// </summary>
OnEveryFocus = 2,
/// <summary>
/// Never selects text (WPF's default attitude)
/// </summary>
Never = 4,
}
public partial class TextBox : DependencyObject
{
public static readonly DependencyProperty SelectAllModeProperty = DependencyProperty.RegisterAttached(
"SelectAllMode",
typeof(SelectAllMode?),
typeof(TextBox),
new PropertyMetadata(SelectAllModePropertyChanged));
private static void SelectAllModePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (d is System.Windows.Controls.TextBox)
{
var textBox = d as System.Windows.Controls.TextBox;
if (e.NewValue != null)
{
textBox.GotKeyboardFocus += OnKeyboardFocusSelectText;
textBox.PreviewMouseLeftButtonDown += OnMouseLeftButtonDown;
}
else
{
textBox.GotKeyboardFocus -= OnKeyboardFocusSelectText;
textBox.PreviewMouseLeftButtonDown -= OnMouseLeftButtonDown;
}
}
}
private static void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
DependencyObject dependencyObject = GetParentFromVisualTree(e.OriginalSource);
if (dependencyObject == null)
return;
var textBox = (System.Windows.Controls.TextBox)dependencyObject;
if (!textBox.IsKeyboardFocusWithin)
{
textBox.Focus();
e.Handled = true;
}
}
private static DependencyObject GetParentFromVisualTree(object source)
{
DependencyObject parent = source as UIElement;
while (parent != null && !(parent is System.Windows.Controls.TextBox))
{
parent = VisualTreeHelper.GetParent(parent);
}
return parent;
}
private static void OnKeyboardFocusSelectText(object sender, KeyboardFocusChangedEventArgs e)
{
var textBox = e.OriginalSource as System.Windows.Controls.TextBox;
if (textBox == null) return;
var selectAllMode = GetSelectAllMode(textBox);
if (selectAllMode == SelectAllMode.Never)
{
textBox.SelectionStart = 0;
textBox.SelectionLength = 0;
}
else
textBox.SelectAll();
if (selectAllMode == SelectAllMode.OnFirstFocusThenNever)
SetSelectAllMode(textBox, SelectAllMode.Never);
else if (selectAllMode == SelectAllMode.OnFirstFocusThenLeaveOff)
SetSelectAllMode(textBox, null);
}
[AttachedPropertyBrowsableForChildrenAttribute(IncludeDescendants = false)]
[AttachedPropertyBrowsableForType(typeof(System.Windows.Controls.TextBox))]
public static SelectAllMode? GetSelectAllMode(DependencyObject @object)
{
return (SelectAllMode)@object.GetValue(SelectAllModeProperty);
}
public static void SetSelectAllMode(DependencyObject @object, SelectAllMode? value)
{
@object.SetValue(SelectAllModeProperty, value);
}
}
在XAML中，你可以这样使用:
<!-- On first focus, it selects all then leave off textbox and doesn't check again -->
<TextBox attprop:TextBox.SelectAllMode="OnFirstFocusThenLeaveOff" />
<!-- On first focus, it selects all then never selects -->
<TextBox attprop:TextBox.SelectAllMode="OnFirstFocusThenNever" />
<!-- Selects all on every focus -->
<TextBox attprop:TextBox.SelectAllMode="OnEveryFocus" />
<!-- Never selects text (WPF's default attitude) -->
<TextBox attprop:TextBox.SelectAllMode="Never" />
哇!读完以上所有内容后，我发现自己不知所措。我从这篇文章中学到了一些东西，并尝试了一些完全不同的东西。当文本框获得焦点时，我使用这个来选择文本:
private void TextField_GotFocus(object sender, RoutedEventArgs e)
{
TextBox tb = (sender as Textbox);
if(tb != null)
{
e.Handled = true;
tb.Focus();
tb.SelectAll();
}
}
将文本框的GotFocus属性设置为该方法。
运行应用程序并在文本框中单击一次，将突出显示文本框中已经存在的所有内容。
如果目标确实是在用户单击文本框时选择文本，这看起来很简单，涉及的代码也少了很多。只是说……
我已经测试了所有的，但只有以下工作:
protected override void OnStartup(StartupEventArgs e)
{
EventManager.RegisterClassHandler(typeof(TextBox), UIElement.PreviewMouseLeftButtonDownEvent,
new MouseButtonEventHandler(SelectivelyHandleMouseButton), true);
EventManager.RegisterClassHandler(typeof(TextBox), UIElement.GotKeyboardFocusEvent,
new RoutedEventHandler(SelectAllText), true);
EventManager.RegisterClassHandler(typeof(TextBox), UIElement.GotFocusEvent,
new RoutedEventHandler(GotFocus), true);
}
private static void SelectivelyHandleMouseButton(object sender, MouseButtonEventArgs e)
{
var textbox = (sender as TextBox);
if (textbox != null)
{
int hc = textbox.GetHashCode();
if (hc == LastHashCode)
{
if (e.OriginalSource.GetType().Name == "TextBoxView")
{
e.Handled = true;
textbox.Focus();
LastHashCode = -1;
}
}
}
if (textbox != null) textbox.Focus();
}
private static void SelectAllText(object sender, RoutedEventArgs e)
{
var textBox = e.OriginalSource as TextBox;
if (textBox != null)
textBox.SelectAll();
}
private static int LastHashCode;
private static void GotFocus(object sender, RoutedEventArgs e)
{
var textBox = e.OriginalSource as TextBox;
if (textBox != null)
LastHashCode = textBox.GetHashCode();
}
这对我来说似乎很有效。它基本上是一些早期帖子的重述。我只是把它放到构造函数的MainWindow.xaml.cs文件中。我创建了两个处理程序，一个用于键盘，一个用于鼠标，并将两个事件导入同一个函数HandleGotFocusEvent，该函数定义在同一个文件的构造函数之后。
public MainWindow()
{
InitializeComponent();
EventManager.RegisterClassHandler(typeof(TextBox),
UIElement.GotKeyboardFocusEvent,
new RoutedEventHandler(HandleGotFocusEvent), true);
EventManager.RegisterClassHandler(typeof(TextBox),
UIElement.GotMouseCaptureEvent,
new RoutedEventHandler(HandleGotFocusEvent), true);
}
private void HandleGotFocusEvent(object sender, RoutedEventArgs e)
{
if (sender is TextBox)
(sender as TextBox).SelectAll();
}
下面是为方便您实现答案解决方案的Blend行为:
一个用于附加到单个文本框:
public class SelectAllTextOnFocusBehavior : Behavior<TextBox>
{
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.GotKeyboardFocus += AssociatedObjectGotKeyboardFocus;
AssociatedObject.GotMouseCapture += AssociatedObjectGotMouseCapture;
AssociatedObject.PreviewMouseLeftButtonDown += AssociatedObjectPreviewMouseLeftButtonDown;
}
protected override void OnDetaching()
{
base.OnDetaching();
AssociatedObject.GotKeyboardFocus -= AssociatedObjectGotKeyboardFocus;
AssociatedObject.GotMouseCapture -= AssociatedObjectGotMouseCapture;
AssociatedObject.PreviewMouseLeftButtonDown -= AssociatedObjectPreviewMouseLeftButtonDown;
}
private void AssociatedObjectGotKeyboardFocus(object sender,
System.Windows.Input.KeyboardFocusChangedEventArgs e)
{
AssociatedObject.SelectAll();
}
private void AssociatedObjectGotMouseCapture(object sender,
System.Windows.Input.MouseEventArgs e)
{
AssociatedObject.SelectAll();
}
private void AssociatedObjectPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if(!AssociatedObject.IsKeyboardFocusWithin)
{
AssociatedObject.Focus();
e.Handled = true;
}
}
}
一个用于附加到包含多个文本框的容器的根:
public class SelectAllTextOnFocusMultiBehavior : Behavior<UIElement>
{
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.GotKeyboardFocus += HandleKeyboardFocus;
AssociatedObject.GotMouseCapture += HandleMouseCapture;
}
protected override void OnDetaching()
{
base.OnDetaching();
AssociatedObject.GotKeyboardFocus -= HandleKeyboardFocus;
AssociatedObject.GotMouseCapture -= HandleMouseCapture;
}
private static void HandleKeyboardFocus(object sender,
System.Windows.Input.KeyboardFocusChangedEventArgs e)
{
var txt = e.NewFocus as TextBox;
if (txt != null)
txt.SelectAll();
}
private static void HandleMouseCapture(object sender,
System.Windows.Input.MouseEventArgs e)
{
var txt = e.OriginalSource as TextBox;
if (txt != null)
txt.SelectAll();
}
}
