C#滚动条的使用

HScroll的min为0，max为20，value为10，则当前水平滚动条显示在中间部位。
当hScroll与绘制的图结合，想要让hScroll滑动一整行，图正好移动到最后，可以这样写：
private void Form1_Paint(object sender, PaintEventArgs e)
{
Graphics g = this.CreateGraphics();
//Region c = g.Clip;
//g.Clip = new Region(new Rectangle(100, 50, 200, 100));
//Scale1(6F);
g.DrawLine(new Pen(new SolidBrush(Color.Red), 1), 100, 500, 1040, 500);
g.DrawLine(new Pen(new SolidBrush(Color.Red), 1), 100, 500, 100, 50);
g.DrawLine(new Pen(new SolidBrush(Color.Red), 1), 100, 50, 1040, 50);
g.DrawLine(new Pen(new SolidBrush(Color.Red), 1), 1040, 500, 1040, 50);
PointF[] m_pointList = new PointF[51];
for (int i = 0; i <= 50; i++)
{
PointF f = new PointF(100 + 14 * i - hScrollBar1.Value, 50 + 9 * i);
m_pointList[i] = f;
}
g.DrawLines(new Pen(new SolidBrush(Color.Blue)), m_pointList);
}
此处，x最大值为700，我们将滚动条的maximum设为700+largeChange，这样，当滚动条滑动到最右侧，图也绘制到了最右侧。
而如果，我们想要放大缩小和滚动相结合，比如，放大到2倍，则每个点的x都扩大为2倍，
for (int i = 0; i <= 50; i++)
{
PointF f = new PointF(100 + 14 2 i - hScrollBar1.Value, 50 + 9 * i);
m_pointList[i] = f;
}
同时，Hscroll的maximum应该设为2*700 + largeChange。

public void UpdateScrollBar()
{
if (viewControl1.Width <= 0 || viewControl1.Height <= 0)
{
return;
}
hScrollBar1.Visible = viewControl1.MyScale > 1.0;

        // 水平滚动条
        int maxMS = 940;//GetMaximumWidth();
        float TimeScale = viewControl1.MyScale;
        float totalWidth = maxMS * (TimeScale - 1);
        // 计算滑块在原有配置下和最大值的相对位置
        //float oldValueRate = 0.0F;
        //if (hScrollBar1.Maximum != 0)
        //{
        //    oldValueRate = hScrollBar1.Value * 1.0F / hScrollBar1.Maximum;
        //}
        hScrollBar1.Maximum = (int)(totalWidth) + hScrollBar1.LargeChange;  //timeAxis.Width / 2;
        //hScrollBar1.LargeChange = (int)TimeScale;
        // 新配置下保持和新的最大值相对位置（不能超过最大可移动范围）
        //hScrollBar1.Value = (int)(hScrollBar1.Maximum * oldValueRate);
        hScrollBar1.Value = 0;
    }

TimeSpan totalTs = m_dateTimeList[m_count - 1].Subtract(m_dateTimeList[0]).Duration();
double totalSeconds = totalTs.TotalSeconds;

        PointF[] pointList = new PointF[m_count];
        for (int i = 0; i < m_count; i++)
        {
            TimeSpan ts = m_dateTimeList[i].Subtract(m_dateTimeList[0]).Duration();
            double sec = ts.TotalSeconds;
            float x = (float)(sec * 940 * m_scale / totalSeconds);
            float y = 500.0f;
            int index = i;
            if (m_maxValue != m_minValue && index < m_count)
            {
                long value = m_dataList[index];
                if (m_units == Units.MB)
                {
                    value /= (1024 * 1024);
                }
                else if (m_units == Units.KB)
                {
                    value /= 1024;
                }
                y = 500 - (value - m_minValue) * 450 / (m_maxValue - m_minValue);
            }
            if (y > 500)
            {
                y = 500;
            }
            if (y < 50)
            {
                y = 50;
            }
            //x = x * m_scale + 100 - m_startX;
            x = x + 100 - m_startX;
            pointList[i] = new PointF(x, y);
        }
        if (pointList.Length > 1)
        {
            Region c = g.Clip;
            g.Clip = new Region(new Rectangle(100, 50, 940, 450));
            g.DrawLines(new Pen(new SolidBrush(Color.Blue)), pointList);
            g.Clip = c;
        }