Question

尝试在C＃和WPF中使用Microsoft Word中的方程式编辑器。 XML无法使用;它必须是纯粹的程序化。

现在我有LineGUIObject : System.Windows.Controls.WrapPanel，就像System.Windows.Controls.TextBox一样，不过只是显示字符串而是按顺序显示List<System.Windows.UIElement>的每个元素。

现在我希望用户能够点击LineGUIObject的实例并输入它。持之以法是我不知道如何捕获用户的点击或阅读他们输入的输入。怎么办呢？

注意：这个问题并不是要求在捕获后如何处理输入;只是如何获得输入。例如，是否有一些event在用户点击它之后会触发？我似乎无法为System.Windows.Controls.WrapPanel找到一个，这可能意味着我需要使用其他类型的对象，或者......？

当前代码：

public class LineGUIObject
    :   System.Windows.Controls.WrapPanel
{
    private List<System.Windows.UIElement> _uiElementList;
    private CursorGUIObject _cursor;
    private int? _cursorIndex;
    public LineGUIObject(System.Windows.Threading.Dispatcher dispatcher)
        : base()
    {
        this.UIElementList = new List<System.Windows.UIElement>();
        this.Cursor = new CursorGUIObject(dispatcher, 25, 1.5, 250);
        this.UIElementList.Add(this.Cursor);

        this.AddText("[junk string just to see this otherwise invisible object while debugging]");
    }
    protected void InterpretUserKeyStroke(/* ??? */)
    {
        //How do we get this method to be called on user input,
        //e.g. when the user types "1"?
        throw new NotImplementedException();
    }
    protected void AddText(string text)
    {
        this.UIElementList.Add(new System.Windows.Controls.TextBlock(new System.Windows.Documents.Run(text)));
        this.UpdateDisplay();
    }
    protected List<System.Windows.UIElement> UIElementList { get { return this._uiElementList; } private set { this._uiElementList = value; } }
    protected CursorGUIObject Cursor { get { return this._cursor; } private set { this._cursor = value; } }
    protected int? CursorIndex
    {
        get { return this._cursorIndex; }
        set
        {
            int? nullablePriorIndex = this.CursorIndex;

            if (nullablePriorIndex != null)
            {
                int priorIndex = nullablePriorIndex.Value;
                this.UIElementList.RemoveAt(priorIndex);
            }

            if (value == null)
            {
                this._cursorIndex = null;
            }
            else
            {
                int newIndex = value.Value;
                if (newIndex < 0)
                {
                    newIndex = 0;
                }
                else
                {
                    int thisListCount = this.UIElementList.Count;
                    if (newIndex > thisListCount) { newIndex = thisListCount; }
                }

                this.UIElementList.Insert(newIndex, this.Cursor);
                this._cursorIndex = newIndex;
            }

            this.UpdateDisplay();
        }
    }

    protected void UpdateDisplay()
    {
        this.Children.Clear();
        foreach (System.Windows.UIElement uiElement in this.UIElementList) { this.Children.Add(uiElement); }
    }
}


public class CursorGUIObject
    :   System.Windows.Controls.WrapPanel
{
    public const double MINIMUM_BLINK_TIME_IN_MS = 5;
    public const double MINIMUM_HEIGHT = 0.5;
    public const double MINIMUM_WIDTH = 0.5;

    private object ToggleVisibilityLock = new object();

    private delegate void TimerIntervalDelegate();

    private System.Windows.Shapes.Rectangle _rectangle;
    private System.Timers.Timer _timer;
    private System.Windows.Threading.Dispatcher _dispatcher;
    public CursorGUIObject(System.Windows.Threading.Dispatcher dispatcher, double height, double width, double blinkTimeInMS)
    {
        this.Dispatcher = dispatcher;

        System.Windows.Shapes.Rectangle rectangle = new System.Windows.Shapes.Rectangle();
        rectangle.Width = width > MINIMUM_WIDTH ? width : MINIMUM_WIDTH;
        rectangle.Height = height > MINIMUM_HEIGHT ? height : MINIMUM_HEIGHT;
        rectangle.Fill = System.Windows.Media.Brushes.Black;
        this.Rectangle = rectangle;
        this.Children.Add(rectangle);

        System.Timers.Timer timer = new System.Timers.Timer(blinkTimeInMS > MINIMUM_BLINK_TIME_IN_MS ? blinkTimeInMS : MINIMUM_BLINK_TIME_IN_MS);
        this.Timer = timer;
        timer.Elapsed += timer_Elapsed;
        timer.Start();
    }
    ~CursorGUIObject()
    {
        System.Timers.Timer timer = this.Timer;
        if (timer != null) { timer.Dispose(); }
    }
    private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        Delegate timerDelegate = new TimerIntervalDelegate(ToggleVisibility);
        this.Dispatcher.BeginInvoke(timerDelegate);
    }
    protected void ToggleVisibility()
    {
        lock (ToggleVisibilityLock)
        {
            if (this.Rectangle.Visibility.Equals(System.Windows.Visibility.Hidden))
            {
                this.Rectangle.Visibility = System.Windows.Visibility.Visible;
            }
            else
            {
                this.Rectangle.Visibility = System.Windows.Visibility.Hidden;
            }
        }
    }
    protected System.Windows.Shapes.Rectangle Rectangle { get { return this._rectangle; } private set { this._rectangle = value; } }
    protected System.Timers.Timer Timer { get { return this._timer; } private set { this._timer = value; } }
    protected System.Windows.Threading.Dispatcher Dispatcher { get { return this._dispatcher; } private set { this._dispatcher = value; } }
}

Answer 1

几乎所有WPF控件都提供对UIElement.PreviewMouseDown Event的访问权限，您可以使用它来监控鼠标点击。因此，此事件允许您监视每个对象的单击时间。接下来，我建议您使用小型Popup控件弹出TextBox，用户可以输入值：

<Popup Name="Popup">
    <Border BorderBrush="Black" BorderThickness="1" CornerRadius="5" Padding="5">
        <TextBox Text="{Binding InputText}" />
    </Border>
</Popup>

根据您设置项目的方式，可以从事件处理程序中打开Popup：

private void YourObject_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
    Popup.IsOpen = true;
}

Answer 2

事实证明LineGUIObject只需要在其构造函数中设置this.Focusable = true;，以便在单击时可以接收键盘的焦点。

现在它可以集中在this.KeyUp += LineGUIObject_KeyUp;也在构造函数中，并且

    protected override void OnKeyDown(System.Windows.Input.KeyEventArgs e)
    {
        this.AddText(e.Key.ToString());
    }

由于我的LineGUIObject嵌套在ScrollViewer，LineGUIObject会在ScrollViewer收到后立即窃取焦点，因此即使这也有问题。这是通过使<ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" Focusable="False"/>无法获得焦点来修复的，即{{1}}。

捕获用户单击并键入自定义WPF TextBox类控件？

2 个答案: