winform水平滚动条联动panel

/// <summary>
/// 窗体加载
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Form1_Load(object sender, EventArgs e)
{
InitialButtons();
}
/// <summary>
/// 往pnlBack中添加button并联动水平滚动条
/// </summary>
/// <param name="a">每行显示的button数，默认为15</param>
private void InitialButtons(int a = 15)
{
//初始化显示在pnlBack里面的button
if (txtCols.Text.Trim() != "")
{
int.TryParse(txtCols.Text.Trim(), out a);
if (a <= 0)
{
a = 15;
}
}
pnlBack.Controls.Clear();
for (int i = 0; i < 60; i++)
{
Button btn = new Button();
btn.Size = new Size(140, 80);
btn.Text = "Text" + (i + 1);
if (i < a)
{
btn.Location = new Point(i * 140 + (i + 1) * 10, 10);
}
else if (i < 2 * a)
{
btn.Location = new Point((i - a) * 140 + (i + 1 - a) * 10, 100);
}
else if (i < 3 * a)
{
btn.Location = new Point((i - 2 * a) * 140 + (i + 1 - 2 * a) * 10, 190);
}
else
{
btn.Location = new Point((i - 3 * a) * 140 + (i + 1 - 3 * a) * 10, 280);
}
pnlBack.Controls.Add(btn);
}
pnlBack.Width = 10 + (10 + 140) * a; //初始化水平滚动条
Hsb.Maximum = pnlBack.Width + 20;
Hsb.Minimum = 0;
Hsb.LargeChange = pnlOwner.Width;
Hsb.SmallChange = 5;
}
//水平滚动条滚动
private void Hsb_Scroll(object sender, ScrollEventArgs e)
{
pnlBack.Left = pnlBack.Left - (e.NewValue - e.OldValue);
}
//更改每行的按钮数目
private void btnOk_Click(object sender, EventArgs e)
{
InitialButtons();
}