如何提高性能超过GDI的绘图图像(未缩放)?

在我的用户控件的绘制处理程序中,我迭代一组预定义的位图对象,然后将它们绘制到客户机区域:

C版本:

private void Control_Paint(object sender, PaintEventArgs e) {
    Graphics g = e.Graphics;
    foreach (BitmapObj bmpObj in _bitmapObjCollection) {
        g.DrawImageUnscaled(bmpObj.Bitmap, bmpObj.Location);
    }
}

VB.NET版本:

Private Sub Control_Paint(ByVal sender As Object, ByVal e As PaintEventArgs) Handles MyBase.Paint
    Dim g As Graphics = e.Graphics

    For Each bmpObj As BitmapObj In _bitmapObjCollection
        g.DrawImageUnscaled(bmpObj.Bitmap, bmpObj.Location)
    Next
End Sub

代码运行良好,但当十几个对象被添加到集合中时,代码开始陷入停顿。我的问题是:有没有办法加快速度?是否可以使用win32 bitblt函数替换DrawImageUnscaled?如果是,怎么办?

谢谢!

注:使用bitblt的谷歌搜索到目前为止只产生了我的屏幕帽样本…