TableLayoutPanel 只能按点找到启动时可见区域中的控件

Question

我有一个带滚动条的 TableLayoutPanel（因为控件的总高度大于 TableLayoutPanel 的高度）。我尝试使用 PageUp 和 PageDown 键以编程方式滚动到 next/previous 行。

滚动有效，但仅限于我想滚动到程序启动时已经在可见区域中的控件。 当我尝试进一步向下移动控件（同时进入可见区域）时，tlp.GetChildAtPoint(new Point(1, tlp.AutoScrollPosition.Y * -1 + 2)) returns null.

有人可以帮我解决这个问题吗？

注意：我找到了解决方法（请参阅我的回答），但我当然愿意接受其他解决方案。

重现问题的代码：

public class FormTLPTest : Form
{
    TableLayoutPanel tlp;

    public FormTLPTest()
    {
        Height = 200;
        Width = 200;
        KeyPreview = true;

        tlp = new TableLayoutPanel();
        tlp.Dock = DockStyle.Fill;
        tlp.CellBorderStyle = TableLayoutPanelCellBorderStyle.Single;
        tlp.AutoScroll = false;
        tlp.VerticalScroll.Visible = true;
        tlp.HorizontalScroll.Visible = false;
        tlp.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 40));

        Controls.Add(tlp);

        tlp.SuspendLayout();

        for (int i = 0; i < 20; i++)
        {
            Label lb2 = new Label();
            lb2.Margin = new Padding(0);
            lb2.Dock = DockStyle.Fill;
            lb2.BackColor = Color.White;
            lb2.Text = "Line " + i;

            tlp.Controls.Add(lb2, 0, i);
            tlp.RowStyles.Add(new RowStyle(SizeType.Absolute, 18));
            tlp.RowCount++;
        }

        tlp.ResumeLayout();
        tlp.AutoScroll = true;

        KeyDown += FormTLPTest_KeyDown;
    }

    private void FormTLPTest_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.PageUp || e.KeyCode == Keys.PageDown || e.KeyCode == Keys.Next)
        {
            Control currentTopControl = tlp.GetChildAtPoint(new Point(1, tlp.AutoScrollPosition.Y * -1 + 2));
            int currentRow = 0;
            if (currentTopControl != null)
                currentRow = tlp.GetPositionFromControl(currentTopControl).Row;

            int nextRow = -1;
            if (e.KeyCode == Keys.PageUp)
                nextRow = currentRow - 1;
            else
                nextRow = currentRow + 1;

            if (nextRow < 0 || nextRow > tlp.RowCount - 1)
                return;

            Control nextTopControl = tlp.GetControlFromPosition(0, nextRow);
            tlp.AutoScrollPosition = nextTopControl.Location;
        }
    }
}

Answer 1

我找到了避免 GetChildAtPoint 方法的解决方案。它检查第一列的每个控件的位置以获得第一个可见列。

我还必须将 .AutoScrollPosition = ... 替换为滚动到最后一个控件，然后滚动到所需的控件（我希望控件位于可见区域的顶部）。

已更改 KeyDown-侦听器：

private void FormTLPTest_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.PageUp || e.KeyCode == Keys.PageDown || e.KeyCode == Keys.Next)
    {
        int currentRow = 0;
        for (int y=0;y<tlp.RowCount;y++)
        {
            Control c = tlp.GetControlFromPosition(0, y);
            if (c.Location.Y >= 0)
            {
                currentRow = y;
                break;
            }
        }

        int nextRow = -1;
        if (e.KeyCode == Keys.PageUp)
            nextRow = currentRow - 1;
        else
            nextRow = currentRow + 1;

        if (nextRow < 0 || nextRow > tlp.RowCount - 1)
            return;

        Control nextTopControl = tlp.GetControlFromPosition(0, nextRow);
        tlp.ScrollControlIntoView(tlp.GetControlFromPosition(0, tlp.RowCount - 1));
        tlp.ScrollControlIntoView(nextTopControl);
    }
}

TableLayoutPanel 只能按点找到启动时可见区域中的控件

TableLayoutPanel is only able to find Controls by Point that were in the visible area on startup

.net

c#

tablelayoutpanel