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.


当前回答

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;
}

其他回答

以下是@Nasenbaer发布的答案的c#版本

private delegate void TextBoxSelectAllDelegate(object sender);

private void TextBoxSelectAll(object sender)
{
    (sender as System.Windows.Controls.TextBox).SelectAll();
}

private void MyTextBox_GotFocus(object sender, System.Windows.RoutedEventArgs e)
{
    TextBoxSelectAllDelegate d = TextBoxSelectAll;

    this.Dispatcher.BeginInvoke(d,
        System.Windows.Threading.DispatcherPriority.ApplicationIdle, sender);
}

而MyTextBox_GotFocus是分配给MyTextBox的GotFocus事件的事件处理程序。

我发现这里给出的答案都没有模仿标准的Windows文本框。例如,尝试在文本框的最后一个字符和文本框右侧之间的空白区域单击。这里的大多数解决方案总是选择整个内容,这使得将文本添加到文本框非常困难。

我在这里给出的答案在这方面表现得更好。它是一个行为(因此它需要来自Blend SDK的System.Windows.Interactivity程序集)。也可以使用附加属性重写。

public sealed class SelectAllTextOnFocusBehavior : Behavior<TextBox>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.PreviewMouseLeftButtonDown += AssociatedObject_PreviewMouseLeftButtonDown;
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        AssociatedObject.PreviewMouseLeftButtonDown -= AssociatedObject_PreviewMouseLeftButtonDown;
    }

    void AssociatedObject_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        // Find the textbox
        DependencyObject parent = e.OriginalSource as UIElement;
        while (parent != null && !(parent is TextBox))
            parent = VisualTreeHelper.GetParent(parent);

        var textBox = parent as TextBox;
        Debug.Assert(textBox != null);

        if (textBox.IsFocused) return;

        textBox.SelectAll();
        Keyboard.Focus(textBox);
        e.Handled = true;
    }
}

这是基于我在这里找到的代码。

我知道这是非常古老的,但这是我的解决方案,它是基于表达式/微软交互性和交互名称空间。

首先,我按照此链接中的说明将交互性触发器放入样式中。

然后就归结为这个

<Style x:Key="baseTextBox" TargetType="TextBox">
  <Setter Property="gint:InteractivityItems.Template">
    <Setter.Value>
      <gint:InteractivityTemplate>
        <gint:InteractivityItems>
          <gint:InteractivityItems.Triggers>
            <i:EventTrigger EventName="GotKeyboardFocus">
              <ei:CallMethodAction MethodName="SelectAll"/>
            </i:EventTrigger>
            <i:EventTrigger EventName="PreviewMouseLeftButtonDown">
              <ei:CallMethodAction MethodName="TextBox_PreviewMouseLeftButtonDown"
                TargetObject="{Binding ElementName=HostElementName}"/>
            </i:EventTrigger>
          </gint:InteractivityItems.Triggers>
        </gint:InteractivityItems>
      </gint:InteractivityTemplate>
    </Setter.Value>
  </Setter>
</Style>

public void TextBox_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
  TextBox tb = e.Source as TextBox;
  if((tb != null) && (tb.IsKeyboardFocusWithin == false))
  {
    tb.Focus();
    e.Handled = true;
  }
}

在我的例子中,我有一个用户控件,其中的文本框有一个隐藏代码。隐藏代码具有处理程序函数。我在XAML中为用户控件设置了一个名称,并将该名称用于元素。这对我来说非常有效。简单地应用样式的任何文本框,你想有所有的文本选择时,点击在文本框。

当TextBox上的GotKeyboardFocus事件触发时,第一个CallMethodAction调用文本框的SelectAll方法。

我希望这能有所帮助。

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" />

在MSDN上有一个非常好的非常简单的解决方案:

<TextBox
    MouseDoubleClick="SelectAddress"
    GotKeyboardFocus="SelectAddress"
    PreviewMouseLeftButtonDown="SelectivelyIgnoreMouseButton" />

下面是背后的代码:

private void SelectAddress(object sender, RoutedEventArgs e)
{
    TextBox tb = (sender as TextBox);
    if (tb != null)
    {
        tb.SelectAll();
    }
}

private void SelectivelyIgnoreMouseButton(object sender,
    MouseButtonEventArgs e)
{
    TextBox tb = (sender as TextBox);
    if (tb != null)
    {
        if (!tb.IsKeyboardFocusWithin)
        {
            e.Handled = true;
            tb.Focus();
        }
    }
}