问题描述

在网上搜索文章后，我想出了一个基于 Winforms 的触摸屏应用程序的设计，该应用程序需要像滚动一样的智能手机.该应用程序本身将在平板笔记本电脑或触摸屏台式机上运行.

After scouring the articles online I have come up with this design for a winforms based touchscreen app that needs smartphone like scrolling. The app itself will run on a tablet laptop or touchscreen desktop.

• 我将所有我想滚动的内容放在一个面板上.
• 将自动滚动设置为 true(将显示滚动条)
• 现在将整个面板放在一个分组框中
• 缩小组合框，直到滚动条被隐藏(视觉上隐藏，不可见 = false)

现在我陷入了有趣的部分.我想我必须处理 mousedown、mouseup 和mousemove 在面板上设置自动滚动位置，这样当有人触摸面板并拖动时，它就会产生滚动魔法.请帮助填写以下方法存根中的几行代码.关于自动滚动位置的 msdn doc 非常令人困惑，因为它返回负数，但需要使用 abs 设置为正数，而不是什么.

Now the fun part I am stuck at. I think I have to handle the mousedown, mouseup & mousemove on the panel to set the autoscrollposition so that when someone touches the panel and drags, it does it's scroll magic. Please help fill in the few lines of code in below method stubs. The msdn doc on autoscrollposition is very confusing since it returns negative numbers but needs to be set to positive with abs and what not.

Point mouseDownPoint;
Point mouseUpPoint;
Point mouseDragPoint;
 private void myPanel_MouseDown(object sender, MouseEventArgs e)
 {
    this.mouseDownPoint = e.Location;
    Console.WriteLine("Mouse down at {0}", e.location);
 }

 private void myPanel_MouseUp(object sender, MouseEventArgs e)
 {
    this.mouseUpPoint = e.Location;
    this.mouseDownPoint = new Point(); //will set for IsEmpty check
    Console.WriteLine("Mouse Up at {0}", e.location);
 }

 private void myPanel_MouseMove(object sender, MouseEventArgs e)
 {
    Console.WriteLine("Mouse at {0}", e.location);
    if (mouseDownPoint.IsEmpty()) //finger is off the touchscreen
       return;
    myPanel.Autocrollposition = ??
 }

谢谢

//更新 - 下面我有试错工作 &测试代码.(未重构).如果有人有更优雅的解决方案，请发布.

    Point mouseDownPoint;
    private void innerpanel_MouseDown(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
            this.mouseDownPoint = e.Location;
    }

    private void innerpanel_MouseMove(object sender, MouseEventArgs e)
    {
        if (e.Button != MouseButtons.Left)
            return;
        if ((mouseDownPoint.X == e.Location.X) && (mouseDownPoint.Y == e.Location.Y))
            return;

        Point currAutoS = innerpanel.AutoScrollPosition;
        if (mouseDownPoint.Y > e.Location.Y)
        {
            //finger slide UP
            if (currAutoS.Y != 0)
                currAutoS.Y = Math.Abs(currAutoS.Y) - 5;
        }
        else if (mouseDownPoint.Y < e.Location.Y)
        {
            //finger slide down
            currAutoS.Y = Math.Abs(currAutoS.Y) + 5;
        }
        else
        {
            currAutoS.Y = Math.Abs(currAutoS.Y);
        }

        if (mouseDownPoint.X > e.Location.X)
        {
            //finger slide left
            if (currAutoS.X != 0)
                currAutoS.X = Math.Abs(currAutoS.X) - 5;
        }
        else if (mouseDownPoint.X < e.Location.X)
        {
            //finger slide right
            currAutoS.X = Math.Abs(currAutoS.X) + 5;
        }
        else
        {
            currAutoS.X = Math.Abs(currAutoS.X);
        }
        innerpanel.AutoScrollPosition = currAutoS;
        mouseDownPoint = e.Location; //IMPORTANT

    }

推荐答案

作为一个组件:

public partial class TouchableFlowLayoutPanel : FlowLayoutPanel
{
    private bool _doTouchScroll;
    private Point _mouseStartPoint = Point.Empty;
    private Point _panelStartPoint = Point.Empty;

    /// <summary>
    ///     Initializes a new instance of the <see cref="TouchableFlowLayoutPanel" /> class.
    /// </summary>
    public TouchableFlowLayoutPanel()
    {
        InitializeComponent();

        Program.mouseFilter.MouseFilterDown += mouseFilter_MouseFilterDown;
        Program.mouseFilter.MouseFilterMove += mouseFilter_MouseFilterMove;
        Program.mouseFilter.MouseFilterUp += mouseFilter_MouseFilterUp;
    }

    /// <summary>
    ///     Initializes a new instance of the <see cref="TouchableFlowLayoutPanel" /> class.
    /// </summary>
    /// <param name="container">The container.</param>
    public TouchableFlowLayoutPanel(IContainer container)
    {
        container.Add(this);

        InitializeComponent();

        Program.mouseFilter.MouseFilterDown += mouseFilter_MouseFilterDown;
        Program.mouseFilter.MouseFilterMove += mouseFilter_MouseFilterMove;
        Program.mouseFilter.MouseFilterUp += mouseFilter_MouseFilterUp;
    }

    /// <summary>
    ///     Handles the MouseFilterDown event of the mouseFilter control.
    /// </summary>
    /// <param name="sender">The source of the event.</param>
    /// <param name="e">
    ///     The <see cref="MouseFilterEventArgs" /> instance containing the event data.
    /// </param>
    private void mouseFilter_MouseFilterDown(object sender, MouseFilterEventArgs e)
    {
        if (!_doTouchScroll && e.Button == MouseButtons.Left)
        {
            _mouseStartPoint = new Point(e.X, e.Y);
            _panelStartPoint = new Point(-AutoScrollPosition.X,
                                                 -AutoScrollPosition.Y);
        }
    }

    /// <summary>
    ///     Handles the MouseFilterMove event of the mouseFilter control.
    /// </summary>
    /// <param name="sender">The source of the event.</param>
    /// <param name="e">
    ///     The <see cref="MouseFilterEventArgs" /> instance containing the event data.
    /// </param>
    private void mouseFilter_MouseFilterMove(object sender, MouseFilterEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            if (!_mouseStartPoint.Equals(Point.Empty))
            {
                int dx = (e.X - _mouseStartPoint.X);
                int dy = (e.Y - _mouseStartPoint.Y);

                if (_doTouchScroll)
                {
                    AutoScrollPosition = new Point(_panelStartPoint.X - dx,
                                                   _panelStartPoint.Y - dy);
                }
                else if (Math.Abs(dx) > 10 || Math.Abs(dy) > 10)
                {
                    _doTouchScroll = true;
                }
            }
        }
    }

    /// <summary>
    ///     Handles the MouseFilterUp event of the mouseFilter control.
    /// </summary>
    /// <param name="sender">The source of the event.</param>
    /// <param name="e">
    ///     The <see cref="MouseFilterEventArgs" /> instance containing the event data.
    /// </param>
    private void mouseFilter_MouseFilterUp(object sender, MouseFilterEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            if (_doTouchScroll && !AutoScrollPosition.Equals(_panelStartPoint) &&
                !_panelStartPoint.Equals(Point.Empty))
            {
                // don't fire Click-Event
                e.Handled = true;
            }
            _doTouchScroll = false;
            _mouseStartPoint = Point.Empty;
            _panelStartPoint = Point.Empty;
        }
    }
}

internal class MouseFilter : IMessageFilter
{
    private const int WM_LBUTTONDOWN = 0x0201;
    private const int WM_LBUTTONUP = 0x0202;
    private const int WM_MOUSEMOVE = 0x0200;

    /// <summary>
    ///     Filters a message before sending it
    /// </summary>
    /// <param name="m">The message to be sent.This message can not be changed.</param>
    /// <returns>
    ///     true to filter the message and prevent it from being sent. false to allow the message to be sent to the next filter or control.
    /// </returns>
    public bool PreFilterMessage(ref Message m)
    {
        Point mousePosition = Control.MousePosition;
        var args = new MouseFilterEventArgs(MouseButtons.Left, 0, mousePosition.X, mousePosition.Y, 0);

        switch (m.Msg)
        {
            case WM_MOUSEMOVE:
                if (MouseFilterMove != null)
                {
                    MouseFilterMove(Control.FromHandle(m.HWnd), args);
                }
                break;

            case WM_LBUTTONDOWN:
                if (MouseFilterDown != null)
                {
                    MouseFilterDown(Control.FromHandle(m.HWnd), args);
                }
                break;

            case WM_LBUTTONUP:
                if (MouseFilterUp != null)
                {
                    MouseFilterUp(Control.FromHandle(m.HWnd), args);
                }
                break;
        }

        // Always allow message to continue to the next filter control
        return args.Handled;
    }

    /// <summary>
    ///     Occurs when [mouse filter up].
    /// </summary>
    public event MouseFilterEventHandler MouseFilterUp;

    /// <summary>
    ///     Occurs when [mouse filter down].
    /// </summary>
    public event MouseFilterEventHandler MouseFilterDown;

    /// <summary>
    ///     Occurs when [mouse filter move].
    /// </summary>
    public event MouseFilterMoveEventHandler MouseFilterMove;
}

internal delegate void MouseFilterEventHandler(object sender, MouseFilterEventArgs args);

internal delegate void MouseFilterMoveEventHandler(object sender, MouseFilterEventArgs args);

internal class MouseFilterEventArgs
{
    /// <summary>
    ///     Initializes a new instance of the <see cref="MouseFilterEventArgs" /> class.
    /// </summary>
    /// <param name="mouseButton">The mouse button.</param>
    /// <param name="clicks">The clicks.</param>
    /// <param name="x">The x.</param>
    /// <param name="y">The y.</param>
    /// <param name="delta">The delta.</param>
    public MouseFilterEventArgs(MouseButtons mouseButton, int clicks, int x, int y, int delta)
    {
        Button = mouseButton;
        Clicks = clicks;
        X = x;
        Y = y;
        Delta = delta;
        Handled = false;
    }

    /// <summary>
    ///     Gets or sets the button.
    /// </summary>
    /// <value>
    ///     The button.
    /// </value>
    public MouseButtons Button { get; set; }

    /// <summary>
    ///     Gets or sets a value indicating whether this <see cref="MouseFilterEventArgs" /> is handled.
    /// </summary>
    /// <value>
    ///     <c>true</c> if handled; otherwise, <c>false</c>.
    /// </value>
    public bool Handled { get; set; }

    /// <summary>
    ///     Gets or sets the X.
    /// </summary>
    /// <value>
    ///     The X.
    /// </value>
    public int X { get; set; }

    /// <summary>
    ///     Gets or sets the Y.
    /// </summary>
    /// <value>
    ///     The Y.
    /// </value>
    public int Y { get; set; }

    /// <summary>
    ///     Gets or sets the clicks.
    /// </summary>
    /// <value>
    ///     The clicks.
    /// </value>
    public int Clicks { get; set; }

    /// <summary>
    ///     Gets or sets the delta.
    /// </summary>
    /// <value>
    ///     The delta.
    /// </value>
    public int Delta { get; set; }
}

static class Program
{
    public static MouseFilter mouseFilter = new MouseFilter();

    /// <summary>
    /// Der Haupteinstiegspunkt für die Anwendung.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.AddMessageFilter(mouseFilter);
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new MainForm());
    }
}

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