动态加载的picturebox，为什么改变不了背景，请高手指点，谢谢！
直接上代码了
public partial class TestForm : Form
{
public TestForm()
{
InitializeComponent();
LoadTheTopMenu();
}
#region
private void LoadTheTopMenu()
{
int w = 0; //增加宽度
int wl = 0;
//int hl = 0;
int i = 1;
for (; i < 3; )
{
PictureBox pic_xt_01 = new PictureBox();
pic_xt_01.Location = new System.Drawing.Point(36 + w, 20);
pic_xt_01.Name = "pic_xt_0" + i;
pic_xt_01.Size = new System.Drawing.Size(78, 72);
pic_xt_01.TabIndex = 2;
pic_xt_01.TabStop = false;
pic_xt_01.Image = Properties.Resources.topMenu_01;
pic_xt_01.Cursor = System.Windows.Forms.Cursors.Hand;
pic_xt_01.MouseEnter += pic_xt_01_MouseEnter;
pic_xt_01.MouseLeave += pic_xt_01_MouseLeave;
pic_xt_01.Click += new EventHandler(pic_xt_01_Click);
Label lab_xt_01 = new Label();
lab_xt_01.AutoSize = true;
lab_xt_01.BackColor = System.Drawing.Color.Transparent;
lab_xt_01.Location = new System.Drawing.Point(62 + wl, 75);
lab_xt_01.Name = "lab_xt_0" + i;
lab_xt_01.Size = new System.Drawing.Size(89, 12);
lab_xt_01.TabIndex = 1;
lab_xt_01.Text = "测试";
lab_xt_01.Cursor = System.Windows.Forms.Cursors.Hand;
panelhead.Controls.Add(lab_xt_01);
panelhead.Controls.Add(pic_xt_01);
w = w + 100;
wl = wl + 100;
i++;
}
}
private void pic_xt_01_MouseEnter(object sender, EventArgs e)
{
setControlBackground((sender as PictureBox), Properties.Resources.topMenu_02);
}
private void pic_xt_01_MouseLeave(object sender, EventArgs e)
{
setControlBackground((sender as PictureBox), Properties.Resources.topMenu_01);
}
private void pic_xt_01_Click(object sender, EventArgs e)
{
setControlBackground((sender as PictureBox), Properties.Resources.topMenu_02);
}
private void setControlBackground(Control col, Bitmap image)
{
col.BackgroundImage = image;
}
#endregion
}
如果要实现背景透明为何不用Panel呢？Panel就可以背景透明，但像这种东西，个人感觉还是自定义控件比较好，最起码效率高，然后自己想要什么样的效率就都可以实现，不受自带控件的限制。
下以文章可以作为参考：
http://bbs.csdn.net/topics/390332398
