为什么我的tablelayoutpanel滚动速度慢？

Question

我创建了一个表单并添加了一个TableLayoutPanel（两者都在代码中生成）。面板有2000行，面板有一个滚动条。当我运行应用程序时，它会在显示表单时冻结。当我只添加1700行时，它会显示表单，当快速向下滚动时，程序会在刷新表单内容之前冻结几秒钟。将行添加到Panel时，我使用SuspendLayout和ResumeLayout。我究竟做错了什么？部分代码：

using System;
using System.Windows.Forms;
using System.Drawing;

namespace xxx
{
    partial class xxx
    {
        public int showForm()
        {
            Form unusedTableForm = new Form();
            unusedTableForm.Text = "Unused IOs";
            unusedTableForm.AutoScroll = true;
            unusedTableForm.AutoSize = true;
            unusedTableForm.MaximizeBox = false;
            unusedTableForm.MinimizeBox = false;
            unusedTableForm.FormBorderStyle = FormBorderStyle.Fixed3D;
            unusedTableForm.StartPosition = FormStartPosition.Manual;
            unusedTableForm.Location = new Point(20, 20);
            unusedTableForm.TopMost = true;
            unusedTableForm.VerticalScroll.SmallChange = 300;

            TableLayoutPanel unusedTable = new TableLayoutPanel();
            unusedTable.RowCount = 1; // +1 for header
            unusedTable.ColumnCount = 3;
            unusedTable.CellBorderStyle = TableLayoutPanelCellBorderStyle.Single;
            unusedTable.AutoSize = true;
            unusedTable.RowCount = 2000;
            for (i = 0; i < unusedTable.ColumnCount; i++)
            {
              unusedTable.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
            }
            for (i = 0; i < unusedTable.RowCount; i++)
            {
              unusedTable.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            }

            // create labels for each cell here

            unusedTable.SuspendLayout(); // to make it fast

            // add labels into cells here

            unusedTable.ResumeLayout();
            unusedTableForm.Controls.Add(unusedTable);

            if (unusedTableForm.Height > 900)
            {
            unusedTableForm.Width = unusedTable.Width + 50;
            unusedTableForm.Height = 920;
            unusedTableForm.AutoSize = false;
            unusedTable.Height = 900;
            }

            unusedTableForm.ShowDialog(); // it freezes here with timeout
        }
    }
}