Question

我有一系列可选的TextBoxes。我需要能够单击其中一个并选择鼠标移动的所有文本框，直到释放单击。

我使用了以下代码但是我无法在其他TextBox上点击MouseMove。它总是击中发出Click的TextBox。

class SelectableTextBox: TextBox
{
    public Boolean IsSelected { get; protected set; }

    public void select(Boolean value)
    {
        this.IsSelected = value;
        if (value)
        {
            this.Background = System.Windows.Media.Brushes.Aqua;
        }
        else
        {
            this.Background = System.Windows.Media.Brushes.White;
        }
    }
}

private void onPreviewMouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
    SelectableTextBox textBox = (SelectableTextBox)sender;

    this.SelectionStartedRight = !textBox.IsSelected;
    textBox.select(!textBox.IsSelected);
}

private void onPreviewMouseMove(object sender, System.Windows.Input.MouseEventArgs e)
{
    SelectableTextBox textBox = (SelectableTextBox)sender;

    if (this.SelectionStartedRight)
    {
        textBox.select(true);
    }
}

private void onPreviewMouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
    SelectableTextBox textBox = (SelectableTextBox)sender;

    this.SelectionStartedRight = false;
}

Answer 1

尝试使用MouseEnter事件代替MouseMove。将MouseEnter附加到您选择的文本框中。这将确保只触发所需的事件处理程序及其代码。

如果您决定继续使用全局处理程序，请在将sender转换为特定控件类型时小心。当不是“预期”控制时，你需要考虑那些时间：

SelectableTextBox textBox = sender as SelectableTextBox;

if (textBox != null)
{
    // The rest of the code here...
}

select是一个Linq关键字，因此您可能希望重命名该方法，以避免任何冲突。虽然我认为这不会引起任何问题，但我会改变它。

您不必遵循此约定，但在C#习惯使用大写字母作为方法的第一个字母。另请注意，类的默认访问修饰符为internal ...只是为了确保您知道这一点，因为您继续开发。

您的上一个方法onPreviewMouseLeftButtonUp(...)中包含以下代码：

SelectableTextBox textBox = (SelectableTextBox)sender;

正如我上面所描述的那样，它不仅不安全，而且它也绝对没有。

最后......这就是我，我可能会移动代码来处理将可选文本框（选中或未选中）的状态更改为其类，因为它属于那里。为什么其他任何东西应该负责它如何处理它的状态。保留他们所属的东西，您可以更轻松地测试，调试和维护代码。不要陷入“我稍后会重构它”陷阱......它很少会发生。

这是我粗略的例子。我让该类处理其MouseEnter事件，并检查当时Mouse.LeftButton是否已关闭。你必须扩展它，但它应该是一个坚实的开始：

在评论中对每个OP的请求进行了一些修改。

预览

<强> XAML：

<Window x:Class="SelectableTextBoxes.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:SelectableTextBoxes" Title="MainWindow" Height="350" Width="525"> <StackPanel> <local:SelectableTextBox Height="20" Width="100" Margin="10"/> <local:SelectableTextBox Height="20" Width="100" Margin="10"/> <local:SelectableTextBox Height="20" Width="100" Margin="10"/> <local:SelectableTextBox Height="20" Width="100" Margin="10"/> <local:SelectableTextBox Height="20" Width="100" Margin="10"/> </StackPanel> </Window>

C＃（请原谅我将SelectableTextBox放入同一个文件中......）：

using System.Windows; using System.Windows.Controls; using System.Windows.Input; using System.Windows.Media; namespace SelectableTextBoxes { // Move this class into its own file (it's here for prototyping). public class SelectableTextBox : TextBox { private bool _isSelected; public bool IsSelected { get { return _isSelected; } set { if (_isSelected != value) { _isSelected = value; // If the value changes, sets new color. SetSelectionColor(); } } } public SelectableTextBox() { // For handling an initial click if it happens in the textbox. PreviewMouseDown += SelectableTextBox_PreviewMouseDown; // For handling selection when mouse enters the textbox // and left mouse button is down. MouseEnter += SelectableTextBox_MouseEnter; // To handle mouse capture (release it). GotMouseCapture += SelectableTextBox_GotMouseCapture; } // Handles the mouse down event within the textbox. void SelectableTextBox_PreviewMouseDown(object sender, MouseButtonEventArgs e) { if (!IsSelected) { IsSelected = true; } // If one of the Shift keys is down, return, since // we don't want to deselect others. if (Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift)) { return; } // This part makes a poor assumption that the parent is // always going to be a Panel... expand on this code to // cover other types that may contain more than one element. var parent = VisualTreeHelper.GetParent(this) as Panel; if (parent != null) { foreach (var child in parent.Children) { // If a child is not of a correct type, it'll be null. var tbx = child as SelectableTextBox; // This is where we check to see if it's null or this instance. if (tbx != null && tbx != this) { tbx.IsSelected = false; } } } } // When textbox receives focus, this event fires... we need to release // the mouse to continue selection. void SelectableTextBox_GotMouseCapture(object sender, MouseEventArgs e) { ReleaseMouseCapture(); } // Sets selection state to true if the left mouse button is // down while entering. void SelectableTextBox_MouseEnter(object sender, MouseEventArgs e) { if (Mouse.LeftButton == MouseButtonState.Pressed) { IsSelected = true; } } // Sets the background color based on selection state. private void SetSelectionColor() { if (IsSelected) { Background = Brushes.LightCyan; } else { Background = Brushes.White; } } } // Window code... should be on its own, but I placed the two // classes together while prototyping. public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } } }

选择一系列文本框

1 个答案: