用鼠标拖动滚动

Question

我正在尝试制作一个可滚动的面板，但没有滚动条，并通过鼠标垂直拖动来滚动......这是迄今为止有人帮助我做的事情......：

 private void panel1_MouseEnter(object sender, EventArgs e)
    {
        panel1.AutoScroll = false;
    }

    private int ValidateChange(int change)
    {
        var padding = -1;
        if (change < 0)
        {
            var max = (from Control control in Controls select control.Top + control.Height + padding).Concat(new[] { int.MinValue }).Max();

            if (max < Height + Math.Abs(change))
            {
                return Height - max;
            }
        }
        else
        {
            var min = (from Control control in Controls select control.Top).Concat(new[] { int.MaxValue }).Min();

            if (min > padding - Math.Abs(change))
            {
                return padding - min;
            }
        }
        return change;
    }

    private void HandleDelta(int delta)
    {
        var change = ValidateChange(delta);

        foreach (Control control in Controls)
        {
            control.Top += change;
        }

    }

    private void panel1_MouseWheel(object sender, MouseEventArgs e)
    {
        HandleDelta(e.Delta);
        base.OnMouseWheel(e);
    }

    private Point _mouseLastPosition;

    private void panel1_MouseDown(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            _mouseLastPosition = e.Location;
        }
        base.OnMouseDown(e);
    }

    public void panel1_MouseMove(object sender, MouseEventArgs e)
    {            
            if ((MouseButtons & MouseButtons.Left) != 0)
            {
                var delta = e.Y - _mouseLastPosition.Y;
                HandleDelta(delta);
                _mouseLastPosition = e.Location;
            }
            base.OnMouseMove(e);

    }

但它走得太快了.. 编辑：鼠标拖动看起来有点奇怪我不知道为什么，当我尝试使用鼠标滚轮时，它会出错并给我这个错误：在 System.Core.dll 中发生了“System.StackOverflowException”类型的未处理异常线var max = (from Control control in Controls select control.Top + control.Height + padding).Concat(new[] { int.MinValue }).Max();

Answer 1

发布的代码仅“滚动”或移动面板水平。要获得垂直滚动效果，请更改：

   Panel pa = ss as Panel; pa.Left = pa.Left + ee.X - pPt.X;

到这里：

   Panel pa = ss as Panel; pa.Top = pa.Top + ee.Y - pPt.Y;

为了有意义，“滚动”或“移动”面板也应该高于封闭的表单，所以改变大小，可能是这样的：

    f2.Size = new Size(400, 300);
    ..
    pan.Size = new Size(400, 600);

并且按钮也应该垂直放置，所以改变：

    b.Left = (b.Width + 12) * (i - 1);

到

    b.Top= (b.Height + 12) * (i - 1);

你在从 cmets 复制时也犯了一个错误：这个：

 pan.Parent = f2;

应该是循环中的最后一行。在循环中添加事件处理程序意味着MouseMove 也被称为 10 倍的移动距离也是十倍。

以下是正确编码后的样子：

要使MouseWheel 工作，您可以这样编码：

 pan.MouseWheel += (ss, ee) =>
 {
      Panel pa = ss as Panel;
      pa.Top += ee.Delta > 0 ? 10 : -10;
 };

更新 看起来您还想限制滚动，以便顶部和底部都不能移动到显示区域中。这是实现这一目标的检查；诀窍是先进行检查，然后再进行移动：

            if (ee.Button.HasFlag(MouseButtons.Left))
            {
                Panel pa = ss as Panel;

                int newTop =  pa.Top + ee.Y - pPt.Y;

                if ((newTop <= pan.Top && newTop + pan.Height > f2.ClientSize.Height) ||
                    (newTop >= pan.Top && newTop <= 0))
                {
                    if (newTop <= pan.Top && newTop + pan.Height > f2.ClientSize.Height) 
                        newTop = f2.ClientSize.Height - pan.Height;
                    pa.Top = newTop;
                }
            }

MouseWheel 代码应该以类似的方式检查和限制！

注意：正确的面板高度在这里至关重要。我最初的示例没有考虑到这一点，因为没有要求滚动限制。你可以像这样动态地得到它：

int panHeight = pan.Controls.Cast<Control>().Select(x => x.Bottom).Max();
pan.Height = panHeight;  // maybe add a small gap here..?

Answer 2

这对我有用。它在所有控件上保留 10 像素的填充。尝试一下，然后根据您的需要进行修改。

如果缺少您需要的东西，请告诉我。

public class ScrollablePanel : Panel {
    private Point _mouseLastPosition;

    protected override void OnMouseDown(MouseEventArgs e) {
        if (e.Button == MouseButtons.Left) {
            _mouseLastPosition = e.Location;
        }
        base.OnMouseDown(e);
    }

    private int ValidateChange(int change) {
        var padding = -1;
        if (change < 0) {
            var max = (from Control control in Controls select control.Top + control.Height + padding).Concat(new[] { int.MinValue }).Max();

            if (max < Height + Math.Abs(change)) {
                return Height - max;
            }
        }
        else {
            var min = (from Control control in Controls select control.Top).Concat(new[] { int.MaxValue }).Min();

            if (min > padding - Math.Abs(change)) {
                return padding - min;
            }
        }
        return change;
    }

    private void HandleDelta(int delta) {
        var change = ValidateChange(delta);

        foreach (Control control in Controls) {
            control.Top += change;
        }

    }

    protected override void OnMouseMove(MouseEventArgs e) {
        if((MouseButtons & MouseButtons.Left) != 0) { 
            var delta = e.Y - _mouseLastPosition.Y;
            HandleDelta(delta);
            _mouseLastPosition = e.Location;
        }
        base.OnMouseMove(e);
    }

    protected override void OnMouseWheel(MouseEventArgs e) {
        HandleDelta(e.Delta);
        base.OnMouseWheel(e);
    }
}